LOW←TECH MAGAZINE English

How to Build a Solar Powered Electric Oven

Mon, 13 Oct 2025 00:00:00 +0000

Image: The insulated solar electric cooker that we build in this manual. Photo by Marie Verdeil.

ARTICLE

STEP BY STEP BUILDING PROCESS

Cooking’s high power use

Electric cooking devices are challenging to operate on an off-grid solar PV system. For example, an electric oven requires between 1,000 and 5,000 watts of power, while electric stove burners have an average power consumption of 1,000 to 3,000 watts per burner. If you want to use an oven and one electric stove burner simultaneously, you need a solar array of at least 32 square meters in optimal weather conditions - just to cook. ¹

You can overcome this problem by storing solar power in lead-acid or lithium-ion batteries. If these batteries are powerful enough, they can temporarily provide you with a higher power supply than your solar array can deliver. Batteries are also necessary if you want to cook after sunset or in bad weather, which is likely the case. Unfortunately, batteries account for 70-90% of the costs and the energy invested in a solar PV system. ²

Cooking thus makes it difficult to completely disconnect a household from the power grid and switch to autonomous, smoke-free, small-scale power production. ³ That is especially so when you have a small budget and limited space for solar PV panels. For example, when I attempted to go off the grid in my apartment in Barcelona by using solar panels on the balcony and window sills, it was mainly the electric cookstove that thwarted my efforts. ⁴

Image: The insulated solar electric cooker that we build in this manual. Photo by Marie Verdeil.

How to adapt an electric cooking device to solar power?

Many of the devices we take for granted nowadays were designed for an era of abundant electricity generated by fossil fuels. However, the electric oven we build in this manual demonstrates that modern appliances can be redesigned for an era of intermittent, less concentrated power sources, such as wind and solar energy. Our oven is powered by a 100-watt solar panel, small enough (50x90cm) to fit on a balcony. Furthermore, it can cook after sunset, without the use of batteries.

The key to significantly reducing the power consumption of a cooking device is thermal insulation. Our electric solar oven has 5 cm of insulation on all six sides. Its power use is further reduced by a lower cooking temperature of about 120°C (248°F). You can cook all food safely at much lower temperatures than those typical in modern cooking devices - it just takes longer.

Our oven is powered by a 100-watt solar panel, small enough (50x90cm) to fit on a balcony.

The key to cooking after sunset without batteries is thermal mass. Rather than storing electricity from solar panels in a battery for operating the cooker at night, the heat supplied by the solar panel during the day is stored in the appliance itself. Because the oven retains a high temperature at sunrise, it’s quickly ready for cooking again in the morning. Connected to a solar panel, it’s almost always preheated and ready to use.

Thermal mass also allows the cooker to continue operating after periods of clouds and rain. Likewise, opening the oven door hardly affects the temperature inside. The heat is stored in the mortar and tiles, and the air temperature quickly returns to normal when the door is closed again.

Our oven is heated by a self-made electric resistance that connects directly to the solar panel, without any intervening battery, solar charge controller, or voltage regulator. To maximize energy efficiency, the oven chamber is dimensioned around a metal oven tray and features a side door. Its shape and weight resemble those of a regular oven.

Image: A drawing of the solar electric tiled cooker. Illustration by Marie Verdeil.

The advantages of solar electric cooking

The device we build in this manual is known as an “insulated solar electric cooker” or “ISEC”. The ISEC is a more recent and more sophisticated version of the “solar box cooker”, which is an insulated wooden box with one or more transparant glass plates on top. When a solar box cooker is put in the sun, its interior reaches temperatures that are high enough to boil water and cook food. ⁵

While an insulated solar electric cooker also consists of a well-insulated box, it does not have a glass plate on top. It’s powered by a solar PV panel instead, which is connected to an electric heating element inside the cooker. One could also describe the ISEC as a fireless cooker with an electric heater inside. ⁶

Image: Two conventional, non-electric solar box cookers. Solar energy enters the glass plate and heats up the interior. Built by Audrey Belliot (Slowlab) and Marie Verdeil. Photo by Marie Verdeil.

Image: An insulated solar electric cooker is powered by a solar PV panel, which is connected to an electric heating element inside the cooker. Photo by Marie Verdeil.

The conventional solar box cooker is a very simple device that works without electricity and is cheap and easy to build. ⁷ By comparison, the ISEC is a bit more complex to build and requires a high-tech solar panel. However, solar electric cooking has several important advantages that can make the extra effort worthwhile:

An electric solar oven can be located inside your kitchen. Conventional solar box cookers only work when they are outside in the sun. That is great for events and picnics, or if you have a garden. However, for many people, it would be more practical to have their cooking appliance in their kitchen. The ISEC makes this possible because only the solar panel needs to be outside. In winter, having the cooker inside will also increase its energy efficiency. It will lose less heat to the environment due to cold and wind.
An electric solar oven can be insulated on all sides. Solar box cookers cannot be insulated on the top side; otherwise, solar radiation cannot enter the appliance. ⁸ In contrast, an ISEC can be insulated on all sides, making it more energy efficient than a non-electric solar box cooker. You can further increase the oven’s insulation by draping one or more wool blankets or carpets over it, which is not possible with a non-electric solar box cooker.
An electric solar oven works well in cloudy weather. Conventional solar cookers require full sun to function effectively. That is especially true for parabolic cookers, which concentrate solar rays at a focal point; however, solar box cookers also exhibit low performance during cloudy weather. In contrast, the electric solar cooker can get around that problem by using more or larger solar PV panels. During sunny days, you can use the excess solar PV capacity for other purposes. ²
An electric solar oven needs no attention. Solar box cookers need to be turned towards the sun at least every 15-30 minutes. Parabolic solar cookers require even more frequent movement. In contrast, an ISEC requires no attention. Of course, you could turn the solar panels towards the sun every 15 minutes, which will speed up the heating of the ISEC’s interior. However, solar panels are less sensitive to solar orientation than solar box cookers. Once you have placed food in the insulated solar electric cooker, you can leave it alone.
An electric solar oven allows you to cook after sunset. By embedding the electric heating element in a material with a high thermal mass, an ISEC can remain at high temperature for many hours after sunset. While several methods exist to add heat storage to a conventional solar cooker, they are complex and don’t work very well. For example, adding thermal mass to a conventional solar box cooker would make it too heavy to move around and follow the sun. An ISEC with thermal energy storage is also heavy, but it can remain stationary.

Our choice of building materials

Low-tech Magazine did not invent the ISEC. Our experiments with insulated solar electric cookers, which began in the summer of 2024, are inspired by the work done at Cal Poly University and Living Energy Farm ⁹¹⁰, which we described in an earlier article on direct solar power. ² We borrowed ideas and knowledge from the manuals made by these pioneers, but we also saw some room for improvements, mostly in the choice of building materials. We also applied the concept of insulated solar cooking to a DIY coffeemaker, for which we will publish a separate manual soon.

Rather than glass wool, sheet metal, and plastic buckets, we have chosen to build our cooking device with tiles, cork, plaster, wood, and mortar.

Rather than glass wool, sheet metal, and plastic buckets, we have chosen to build our cooking device with tiles, cork, plaster, wood, and mortar. These materials are easier to obtain and to work with, and they are more aesthetically pleasing. We aimed to design an appliance that people would actually want to see in their kitchen, and which can be built and repaired with only a few standard tools. It remains to be seen how durable our material choices will be in the long term. Still, for now, the device has been operated extensively for several months without any significant signs of damage.

Image: Some of the materials we have used. Photo by Marie Verdeil.

Our solar electric cooker consists of several key components: the structure (a wooden box), the electric heating element (nichrome wire), the insulation (cork), the thermal mass (mortar and tiles), and a solar PV panel.

Ceramic & terracotta tiles

The use of tiles is the distinctive feature of our design. Most ISECs built to date use aluminum for the inside oven compartment and metal or plastic (for example, a bucket) for the outside. However, making a water-tight aluminium box is not easy and requires specialist tools. Plastic works well as an outer shell, but it looks rather bad and may become brittle over time.

The use of tiles is the distinctive feature of our design.

In our oven, thick terracotta tiles form the cooking chamber, providing a waterproof, fireproof, and easy-to-clean interior surface. The tiles prevent water from entering the insulation layer or the electrical system, and they ensure that the insulation does not become damaged by heat. ¹¹ We also put tiles on the outside of the cooker, where they please the eye, protect the device against water damage from the outside, and make it easy to clean.

Image: The oven chamber, made from thick terracotta roof tiles. Photo by Marie Verdeil.

Tiles are easy and cheap to obtain: we collected all of them on the streets of Barcelona. Tiling can be accomplished with minimal skills and tools. You need a tile cutter if you want to cut tiles shorter, but you can avoid this by choosing the right size of tiles or by applying a “trencadís” technique, made famous by architect Antoni Gaudí. This technique involves dropping tiles so that they break and rearranging them altogether as a mosaic.

Using a tile cutter requires some practice, and you will likely break a few tiles as you learn. Make a groove in the tile by passing the sharp tungsten wheel several times across it. Then apply some pressure on both sides with your hands: the tile should break along the line. Some tiles are more challenging to cut than others. To fix tiles to wood, use a cement-based adhesive mortar. To attach tiles to cork, we applied a layer of plaster bands in some cases, as mortar doesn’t adhere well to cork. Use grout to seal the joints between tiles.

Cork or wool for insulation

Insulation is key to the workings of all solar cookers, including the ISEC. It’s the insulation that allows cooking with a very small solar panel. The heat accumulates over time because the insulation slows down the release of heat from the cooker to the outside environment. For insulation, we use a 5 cm layer of expanded cork on all six sides of our device. Expanded cork is a natural insulation material that provides excellent insulation. It’s made from cork waste, bound using steam. Standard cork sheets also work well.

For insulation, we use a 5 cm layer of expanded cork on all six sides of our device.

Cork is expensive, and it’s not a material you easily find on the streets. You can obtain a cheaper but more labour-intensive insulation material by cutting up discarded and second-hand wool clothes and blankets. Apart from cork and wool, there exist many other insulating materials. However, many are toxic or unpleasant to work with, and unlike cork and wool, they are often flammable. Cotton and cellulose are cheap and sustainable (waste) materials, but they do not insulate as well as cork or wool.

Image: The expanded cork insulation. Photo by Marie Verdeil.

Mortar for heat storage

We made the base of our cooking device out of mortar, a material that retains a lot of heat. Thermal mass is the key to cooking after sunset. The solar panel stores heat in the oven rather than electricity in a battery. The mortar serves a dual function: it also safely encapsulates the electric heating element (see below). Every ISEC with a self-built heating element will have some thermal mass; however, we have made a thicker slab to enhance heat storage. The tiles of the oven chamber provide extra thermal mass.

The solar panel stores heat in the oven rather than electricity in a battery.

Mortar is composed of cement, sand, and water. Sold as a powder in bags, it must be mixed with water before application. You can also buy a bag of cement and mix it with sand and water to obtain mortar. Follow the instructions on the packaging for the powder-to-water ratio. Once cured, which takes several days, mortar becomes (and remains) hard. There’s no need to use refractory cement, which is made to withstand high temperatures in fireplaces and pizza ovens, because the temperature in our oven is not that high. Sand is an alternative material with a high thermal mass.

Heating element and electric system

Our oven is heated by an electric resistance element, which is connected directly to the solar panel. We initially used commercial heating elements in our prototypes, which yielded disappointing results. Therefore, we decided to build our own, based on the manual provided by the Living Energy Farm. ¹² Building your own heating element involves extra work, but it’s worth the effort.

Many commercial heating elements have built-in thermostats, which can complicate temperature regulation inside the oven. They also require a voltage input that does not align with the voltage output of most solar panels, which introduces the need for an extra electronic component (a buck converter). Securely fixing commercial heating elements proved to be difficult as well, and we had trouble keeping moisture away from the electrical system; at one point, this resulted in an electrical fire.

Building your own heating element involves extra work, but it’s worth the effort.

By embedding a self-made heating element in a mortar base, we solved all these problems. A custom-made electric resistance consists of a circuit made of nichrome wire, which is an alloy of nickel and chrome. The length and thickness of the nichrome wire determine its heat dissipation and power consumption, allowing you to precisely scale the circuit according to the voltage and current produced by your solar panel. You connect the nichrome circuit to the electric cables of the solar panel, with a short section of heat-resistant electric cable in between (see our manual).

Our solar electric cooker features a thermal fuse and an internal thermostat, both of which are embedded in the mortar layer. However, these components are not necessary when operating the oven on a solar panel without a battery. Nature already provides the thermostat: once the sun goes down, the heating element stops working, making it unlikely that the oven overheats.

Image: Building your own heating element involves extra work, but it’s worth the effort. Photo by Marie Verdeil.

Image: The thermal switch and fuse are seen on the first layer of mortar. Photo by Marie Verdeil.

How to use the solar electric oven

Our cooking appliance can be used to cook raw food (vegetables, grains, meat, fish). It can also work as a (slow) microwave oven, warming up leftovers or a ready-made meal.

Food safety

Our oven reaches a maximum cooking temperature of about 120°C (248°F). To avoid food poisoning from potentially dangerous bacteria, food should either be refrigerated or heated to a minimum temperature of between 58 °C and 74°C (136°F-165°F), depending on the type of food, for at least 15 seconds. Cooked vegetables and fruits must reach a temperature of 58°C (136°F). Most meats and seafoods can be safely cooked at 63°C (145°F). Ground meats require a temperature of 71°C (160°F), and leftovers and poultry should reach 74°C (165°F). We monitor the temperature of the food using a food thermometer, which we inserted through the chimney hole at the top.

Image: Food made in the electric solar oven. Photo by Marie Verdeil.

Keep in mind that the temperature inside the oven will drop once you put the food inside. You should not put frozen food inside, because the temperature will drop spectacularly, and it may take many hours before a safe cooking temperature is restored. For the same reason, the oven should be preheated before the food is placed inside. However, because it’s connected to a solar panel, our oven will be at a sufficiently high temperature for most of the time. You should not keep food in the solar cooker overnight, unless you are sure it maintains a safe temperature until the morning (our cooker does not).

Image: Slow-cooked food (before and after cooking). Photo by Marie Verdeil.

Cooking time

It’s perfectly possible to build an insulated solar electric cooker that cooks food just as fast as a normal oven (see further). However, it makes a lot of sense to build a low-temperature, insulated “slow cooker” instead. First, it allows you to cook with a smaller solar panel. Second, slowly cooked food tastes better and retains more of its nutrients. Third, at lower cooking temperatures, food cannot burn and for that reason you don’t need to stir it either. The inconvenience of a longer cooking time is thus compensated for by a more relaxed and easier cooking process.

On average, it takes about twice as long to cook food compared to using a conventional oven. Most meals we make, cooking raw food, take between two and four hours. Heating leftovers or a ready-made meal takes about one hour. These time spans were measured in optimal weather conditions and with a preheated oven.

Cooking after sunset

Due to the cooker’s high thermal mass, it will take several hours to heat it when you first connect it to a solar panel. However, from the second day onwards, the solar panel will keep the cooker at a continuously high temperature, even for many hours after sunset. When fully charged at sunset, reaching a temperature of approximately 120°C (248°F), our electric cooker maintains a sufficiently high temperature to cook for 4-5 hours. Once the food gets in, the temperature drops but remains high enough (above 80°C/176°F) to cook food safely. The stored heat that remains at the end of the night allows us to restart the cooking process quickly in the morning - our oven is still above 40 or 50°C (104-122°F) at sunrise.

The stored heat that remains at the end of the night allows us to restart the cooking process quickly in the morning.

Draping one or more wool blankets over the oven at sunset further increases the heat storage, allowing for cooking a meal even later in the evening, or starting cooking even earlier the next day. You can also use blankets to raise the energy efficiency of the oven during the day, resulting in a higher cooking temperature.

Moisture

Depending on the food you prepare, excessive moisture in the cooking chamber can be a problem. The water in the food may evaporate and collect in the oven space. Therefore, our oven has a small chimney through which the moisture can escape. It can be closed with a cork cap if you want to keep the moisture inside. It is a good idea to leave the oven door open occasionally so that any moisture in the insulation layer can evaporate.

Alternative cooker designs

Because we shaped our cooker around an oven tray, it’s mostly suited for oven dishes. However, other designs are possible. An earlier prototype we built has a heat chamber the size of a soup pot, and so that one is better suited to prepare stews and soups. Whatever form you choose, it’s always a good idea to dimension your cooker around a specific cooking utensil. If you put a small pot into a large oven chamber, you will waste a significant amount of energy heating empty space.

Image: An earlier prototype we built has a heat chamber the size of a soup pot, and so that one is better suited to prepare stews and soups. Photo by Marie Verdeil.

Thicker insulation

The thicker the insulation layer, the more energy efficient the oven will be. A thicker insulation layer allows you to use a smaller solar panel for the same cooking time, or a faster cooking time using the same solar panel. A thicker insulation will also improve the heat storage. However, keep in mind that the device’s volume will increase exponentially. Another 5 cm of insulation on all six sides would have made our oven’s size unpractical for most kitchens.

Higher cooking temperature

If you want a solar electric cooker that cooks faster at a higher temperature, you should choose a larger solar panel and a more powerful heating element, and you should raise the setting of the thermostat and thermal fuse. Adding extra insulation also accelerates the cooking time. However, please note that we did not test our building materials at higher temperatures; therefore, proceed at your own risk.

Much depends on the local customs surrounding eating times, especially dinner. For example, European dinner times vary from about 17:00 to 19:00 in northern countries to between 21:00 and 23:00 in southern countries. The early dinner times in the north align with solar cooking. However, the late dinner times in the south would require more powerful cookers with higher temperatures and more thermal storage to cook after sunset, or to safely store a warm dish prepared in the morning.

More or less heat storage

While a solar electric cooker always needs insulation, you can build it with little or no thermal mass. The choice depends on how you want to use the device. With little to no thermal mass, the cooking appliance will heat up and cool down relatively quickly, and it will be somewhat lighter. But it won’t be able to cook after sunset. Many of the ISECs built by others are of this type.

On the other hand, it’s also possible to create a larger version of our solar cooker that can be used to cook for 24 hours a day. Add more thermal mass, insulation, and consider a higher oven temperature, as well as using a larger solar panel and a more powerful electric resistance. Such a cooking device would always be ready to use immediately, without any need for electricity storage, and it could work in industral kitchens or as a community cooking appliance.

You could also build a solar electric cooker with a heat storage consisting of metal rather than mortar. It does not allow you to cook after sunset, but it does enable you to reach higher cooking temperatures for a short time. That makes it possible to bake and fry food.

Step by step buiding guide

Image: Exploded isometric drawing of our insulated solar electric oven. Illustration by Marie Verdeil.

What you need

Cooking utensil

Oven tray. To hold the food that you are cooking in the oven. This tray, which can be made of metal, ceramics, or heat-resistant glass, is the first thing to obtain, as you will dimension the oven around it.

Electric heating element & electrical system (see our separate manual)

100W solar panel.
Nichrome wire.
Heat-resistant electric cable.
Thermal switch.
Thermal fuse.

Structural materials

Wood boards. The oven is built around a wooden structure. You can reuse an existing box or make it from scratch. Reclaimed wood or chipboard is fine, since none of it will be visible.
Tiles. We use tiles for both the interior of the cooking chamber and the exterior of the oven.
Wood screws.
Hinges and hooks. To attach the oven door.
Feet for the oven. We made these out of wood. Feet make it easier to lift and move the oven, and they protect the oven against water damage from below.
Handle for the oven door. We made one out of wood.

Insulation materials

Expanded cork boards. We used 5 cm thick expanded cork boards as insulation on all sides. We used roughly 1 m2 of expanded cork. You can also use regular cork or wool insulation. Avoid flammable materials such as cotton, wood chips, or any oil-based insulation material. Cork and wool are fire-resistant materials.
Thin cork sheets (4 mm). You place them as a sealant between the oven door and body. You also use them to fill in the height differences between the expanded cork layers above the oven chamber.

Heat storage material

Construction mortar. We use mortar to provide thermal mass for heat storage and to embed the electric resistance heater.

Fixing & filling materials

Adhesive mortar. To fix the tiles to wood and cork surfaces.
Grout. To fill up the space between the tiles.

Extra components

Food thermometer. You need one with a long sensor, as it will have to travel through the thick insulation layer at the top to reach the food.
Chimney pipe. Roll a tube of thin aluminum sheet, which you can cut out of a soda can. Alternatively, buy a metal tube of the correct size.

Tools

Screwdriver
Wood saw
Drill (you need a concrete drill bit for the chimney opening)
Soldering iron and tin
Tile cutter (optional if you find the right size of tiles)
Measuring tools
Utility knife
Mortar trowel and mixing container

Step 1: Build the structure

Image: Step-by-step instructions (fig 1. to 4.). Illustration by Marie Verdeil.

Obtain an oven tray and measure it. We dimensioned our cooking device around a stainless steel tray approximately the size of an A4 sheet: 20 cm x 27 cm.
fig 1. — Using tiles, create a box around the tray with enough room to slide in and out easily. The box will become the inner chamber of the solar cooker. For now, keep the structure together with tape. When determining the dimensions of the heating chamber, leave some space at the top of the oven tray to allow for heat circulation. Ideally, you find tiles that have the correct dimensions. Otherwise, cut the tiles to the correct dimensions using a tile cutter.
Measure the exterior dimensions of the tiled oven chamber to calculate the dimensions of the wooden box that will surround it. Add 5 cm of space on all six sides to fit the expanded cork layer. At the bottom, add about 2-3 cm extra to account for the mortar, which will embed the heating element. Add 5 mm to the dimensions on all sides to ensure everything fits.
fig 2. — Build the wooden box according to the calculated dimensions (don’t forget to add the wood thickness). Screw the wood together in a way that allows for the removal of the upper part later in the building process (see step 3). Measure everything a few times before you start cutting the wood, as it’s easy to make mistakes.
fig 2-3. — To make sure that the door neatly aligns with the rest of the wood box, build the structure as a whole and then cut away (saw) the door part off the box. The door part needs to be 6 cm deep to fit in the insulating cork layer and the oven chamber tile on that side.
fig 4. — Once you have cut the wood, unscrew the top board to gain better access inside.

Image: The oven chamber inside the wood structure. The space in between will be filled up with cork insulation and a mortar layer at the bottom. Photo by Marie Verdeil.

Step 2: Make the electric heat resistance

Create a resistive heating element using Nichrome wire. See our separate manual for instructions.

Step 3: Add insulation, create the heat storage and add the electric heat resistance

Image: Step-by-step instructions (fig 5. to 8.). Illustration by Marie Verdeil.

fig 5. — Using a thin saw or utility knife, cut and glue the expanded cork insulation boards to cover all sides of the area. You can use wood glue or hot glue. Keep the top board apart to add it later.
fig 6. — Mix some construction mortar with water and create a layer of about 10-15 mm on the bottom cork layer. Leave it to set for a couple of hours.
fig 6. — At the back of the box, about 10mm above the mortar layer, pierce a hole through the cork and wood to channel the electric cables through.
fig 7. — Place the resistance circuit on top of the mortar bed and drive the heat-resistant cable endings through the hole in the back of the box. Make sure the nichrome wires don’t cross or touch, and that the (optional) fuse and thermal switch are also lying on top of the mortar.
fig 8. — Pour another 10-15 mm of mortar to cover the circuit.

Image: The first layer of mortar with the nichrome circuit, thermal switch, and thermal fuse on top. All these components will be hidden in the second layer of mortar. Photo by Marie Verdeil.

Phase 4: Fix the cooking chamber in place and complete the insulation

Image: Step-by-step instructions (fig 9. to 16.). Illustration by Marie Verdeil.

fig 9. — Take the tiles you prepared for the inner chamber. Place some mortar at the back of the bottom tiles and press them onto the mortar bed.
fig 10. — Using adhesive mortar, fix the remaining tiles to the sides and back of the cork boards, recreating the oven chamber that you taped together in step 1.
fig 11. — Using a drill with a concrete drill bit, make a 10-12 mm hole in the center top tile to fit an air vent chimney.
fig 11. — Lay the remaining top tiles to rest on the edges of the side tiles with a bit more mortar. It is a good idea to tilt the top tiles slightly to one side to guide condensation moisture away from the food tray.
fig 12. — Before placing back the top cork board on top of the inner tile chamber, mark the position of the chimney and drill through the cork and wooden boards.
fig 12-13. — Place the top corkboard on the top tiles with a bit of adhesive mortar and screw back the top wooden board to close the box. If there are some air gaps, fill them in with cork scraps or sheets to prevent heat leakage.
fig 14. — Glue 4 mm thick cork sheets to the box insulation that surrounds the oven chamber on the front. Use wood glue. This extra layer helps to close the door tightly and prevents any heat from escaping.
fig 15. — Insulate the door by fitting a 5 cm expanded cork board inside with wood glue. Using a bit more adhesive mortar, place the last tile on the door, making sure it aligns and closes the inner chamber when the wood box is closed.
fig 16. — Glue another 4mm corksheet to mirror the chamber’s edge.

The box is now mostly finished. Let everything dry/cure for at least 48 hours.

Image: Fixing the cooking chamber. Photo by Marie Verdeil.

Step 5: Finishing touches

Image: Step-by-step instructions (fig 17. to 19.). Illustration by Marie Verdeil.

fig 17. — Tile the box top to make it waterproof and heat-resistant (you can put the oven tray there when it comes out of the oven). Ensure that you leave a hole for the chimney.
Make and insert the chimney. Fit it into the hole you made.
Grouting. Seal the inner tile chamber with grout to prevent moisture from entering the cork insulation. Do the same for the exterior tiles and for the joint with the chimney. We also added plaster on the sides to protect the wood.
fig 18. — Add a handle to the door.
fig 19. — Add hinges to attach the door to the oven body using screws. Place a metal latch on each side to tightly lock the door during operation.
Add small feet to the oven to make it easier to lift and to protect it against water damage.
The oven is finished!
Connect the heat-resistant cables sticking out of the oven to the wires of the solar panel. Insert an on/off switch between them (on the positive wire).

Image: Some assembly steps for the oven (from left to right): Fig.1: Drilling a hole for the chimney, with all insulation in place. Fig.2: Extra layer of cork to cover the door and box insulation. Fig.3: Tiling the exterior of the solar electric oven. Fig.4: Grouting. Photos by Marie Verdeil.

Credits

Concept: Kris De Decker, with input from Marie Verdeil.
Design: Marie Verdeil, with input from Anna Mareschal de Charentenay.
Construction & documentation: Marie Verdeil, with assistance from Hugo Lopez.
Design & construction of two earlier prototypes: Vaiva Vinskaité, with input from Kris De Decker and Marie Verdeil.
Thanks to: Samira Allaouat & Alexandra Tollefsrud for the tiles. AkashaHub Barcelona for the workspace. Living Energy Farm & Cal Poly for their pioneering work on insulated solar electric cookers.

In affluent, industrialised societies, cooking is rarely seen as a problem when it comes to resource use and carbon emissions. For example, in the US, only around 5% of a household’s energy use is attributed to cooking devices (such as stovetops, ovens, microwaves, and water kettles). However, while cooking requires relatively little energy, it requires a lot of power. Energy consumption equals power consumption multiplied by time. Since cooking devices are only used for a short time during the day, their energy consumption is relatively low. However, their high power use makes it challenging to operate them on an off-grid solar PV system. ↩︎
Direct Solar Power: Off-Grid Without Batteries, Kris De Decker, Low-tech Magazine, August 2023. https://solar.lowtechmagazine.com/2023/08/direct-solar-power-off-grid-without-batteries/ ↩︎ ↩︎ ↩︎
Too Much Combustion, Too Little Fire, Kris De Decker, Low-tech Magazine, December 2019. https://solar.lowtechmagazine.com/2019/12/too-much-combustion-too-little-fire/ ↩︎
How to Get Your Apartment Off the Grid, Kris De Decker, Low-tech Magazine, May 2016. https://solar.lowtechmagazine.com/2016/05/how-to-get-your-apartment-off-the-grid/ ↩︎
The first recorded use of the solar box cooker goes back to the eighteenth century when the increased use of glass made people aware of its ability to trap solar heat. For more information, see Hirst, Eric. “A golden thread: 2500 years of solar architecture and technology: by Ken Butti and John Perlin Cheshire Books, distributed by Van Nostrand Reinhold Company, New York and London, 1980, 304 pp,£ 11.95.” (1981): 167. /// Daniels, Farrington. Direct use of the sun’s energy. Yale University Press, 1964. /// Telkes, Maria. “Solar cooking ovens.” Solar Energy 3.1 (1959): 1-11]. ↩︎
If We Insulate Our Houses, Why Not Our Cooking Pots?, Kris De Decker, Low-tech Magazine, July 2014. https://solar.lowtechmagazine.com/2014/07/if-we-insulate-our-houses-why-not-our-cooking-pots/ ↩︎
Find an example of a manual here: https://reclaimdesign.org/diy-solar-oven ↩︎
Although glass plates reduce the heat losses from the oven interior somewhat, they cannot offer the same level of thermal resistance as a thick layer of wool or cork. ↩︎
See: https://sharedcurriculum.peteschwartz.net/isecooker-construction/ ↩︎
See: https://livingenergyfarm.org/insulated-solar-electric-cooker/ ↩︎
It may seem unusual to build an oven from materials such as wood, cork, or wool. However, the temperature reached inside our oven does not pose any risk for these materials. Cork and wool are thermally stable up to approximately 200°C and start to degrade above that temperature. They are fire-resistant materials: they don’t ignite and won’t spread fire. Wood does not ignite at temperatures below 250ºC. Furthermore, all these materials are separated from the heating element and the interior oven chamber by mortar and tiles, which resist much higher temperatures. When we had an electrical fire in one of our first prototypes, the fire did not spread. ↩︎
See: https://conev.org/ISECmanual14.pdf ↩︎

How to Assemble an Electric Heating Element from Scratch

Sun, 12 Oct 2025 00:00:00 +0000

Image: A removable heat brick, consisting of a nichrome circuit sandwiched between two identical tiles. It rests upon an insulated solar electric cooking device. Photo by Marie Verdeil.

This manual documents the building of an electric resistance heating element that is directly connected to a solar panel, without a battery, charge controller, or voltage regulator in between. The heating element is used in the insulated solar electric cooker that we describe in another manual, and in the solar-powered coffee maker and footstove that we will document in forthcoming manuals. We also describe a method to make a removable heat brick, which we use to replace the commercial heating elements in some earlier electric solar cooker prototypes we made.

A custom-made electric resistance consists of an electric circuit made of nichrome wire, enclosed in a mortar layer. The length and thickness of the nichrome wire determine its current draw at a certain voltage, meaning that you dimension the circuit to your solar panel voltage and power rating to optimize heat generation. The nichrome circuit is connected to the electric cables of the solar panel, with a short section of heat-resistant electric cable in between. ¹

Why build an electric resistance heating from scratch?

We initially used commercial heating elements in our first solar oven prototypes, which yielded disappointing results. Therefore, we decided to build our own, based on the manual provided by the Living Energy Farm. Building your own heating element involves extra work, but it’s worth the effort. It’s also a lot cheaper.

Many commercial heating elements have built-in thermostats, which can complicate temperature regulation inside the oven. They also require a voltage input that does not align with the voltage output of most solar panels, which introduces the need for an extra electronic component (a buck converter). Securely fixing commercial heating elements proved to be difficult as well, and we had trouble keeping moisture away from the electrical system, which at one point resulted in an electrical fire. By embedding a self-made heating element in a mortar base, we solved all these problems.

Image: Our first solar oven prototype was powered by three commercially available heating elements, with disappointing results. Photo by Kris De Decker.

What is electric resistance heating?

Electric resistance refers to the difficulty that the flow of electric current encounters when it passes through a material. It’s comparable to friction in mechanical systems. Resistance creates heat, as described by Joule’s Law. Electric resistance is measured in ohms (Ω).

The resistance of a piece of wire depends on its material’s resistivity, but also on its length and thickness. Metals have low electrical resistance, meaning that electricity easily flows through them; they are called “conductors”. For example, electric wires are usually made of copper, which has very low electric resistance.

In contrast, materials such as plastic, rubber, and ceramics have very high electric resistance, meaning that electricity doesn’t flow easily through them. These materials are known as “insulators”. For example, electric wires are encapsulated in plastic, which makes them safe to touch.

Electric heating elements, such as those used in ovens, toasters, and hair dryers, are commonly made of nichrome wire, an alloy of nickel and chromium that has relatively high resistance for a metal. Electrons can pass through, but because they encounter quite some resistance, the nichrome wire dissipates a lot of heat. It glows orange when it heats up.

Image: A nichrome wire in a hair dryer. Photo by Dasha Ilina.

What you need

In the components list below, we link to Amazon, using it as a global inventory of components. Feel free—and be encouraged—to buy the components locally, or scavenge them from old appliances. We do not earn anything if you purchase on Amazon.

Nichrome wire. Other example. Nichrome wire is sold in either bobbins or spools. You can also scavenge it from old ovens, toasters, hair driers, and other electric heating devices.
Heat-resistant electric cable. These electric wires are encapuslated in silicone mesh rather than plastic.
Thermal switch (optional).
Thermal fuse (optional).
Construction mortar for encapsulating the nichrome circuit.
Thick tiles (in case you build a removable heat brick).

Image: The nichrome circuit, soldered to a pair of heat-resistant electric cables. Photo by Marie Verdeil.

Calculate the resistance value

The challenge in building an electric resistance heating element is determining the correct length of the nichrome circuit to match the voltage and current rating of the power source.

To determine the length of the nichrome circuit, you need to calculate the desired resistance value that corresponds to your power source. You can calculate it using Ohm’s law, which defines the relation between voltage (Volts, V), current (Ampere, A), and resistance (Ohm, Ω):

Resistance (Ω) = U (V) / I (A)

To determine the voltage and current values of your solar panel, refer to the label attached to the back of the panel.

For the voltage, check the “Maximum Power Voltage (Vmax)” or “Voltage at Pmax”. That refers to the maximum voltage that a solar panel can provide when connected to an electric circuit. Ignore the “Voltage Open Circuit (VOC)”, which is the maximum voltage the solar panel produces if nothing is attached to it.

For a so-called 12V solar panel (so-called because it’s typically used in conjunction with a 12V battery and solar charge controller), the Vmax is approximately 18V. For a so-called 24V solar panel (meant to be used in combination with a 24V battery and charge controller), it’s around 36V.

For the current, check the “Maximum Power Current (IMP)” or “Current at Pmax”. Ignore the “Short Circuit Current”. If the label is missing, measure the voltage with a multimeter. You can calculate the current once you know the voltage and power output: electric current equals the power output (100W in our case) divided by the voltage (18V in our case). The maximum current that our 100W solar panel can produce is therefore 5.55 A.

Once you know the voltage and current of your solar panel, you can calculate the desired resistance value for the heating element using Ohm’s Law. In our case:

18 (V) / 5.55 (A) = 3.24 Ω

Calculate the length of the heating wire

The next step is to cut a piece of nichrome wire that has a resistance of 3.24 Ω. Nichrome wire is sold in various thicknesses, each with a different resistance value. The thinner (and longer) a resistive wire is, the higher its resistance will be. The resistance of a nichrome wire is indicated in ohms per distance (for example, Ω/m).

We purchased a relatively thin Nichrome wire with a rated resistance of 8.71 Ω/m. Following the mathematical Rule of Three, based on the resistance per meter, we find that our nichrome circuit needs to be 37.2 cm long to have a resistance value of 3.24 Ω: (100 * 3.24) / 8.71 = 37.2 cm. If you start with a different thickness of Nichrome wire (anything goes), you will obtain a different length.

Don’t trust the labeling

Unfortunately, the resistance value on the nichrome wire packaging isn’t always exact. To obtain a more accurate measurement, cut precisely one metre of nichrome wire and connect it to the solar panel (or to an 18V test station - see further below) with a watt-meter or multimeter in between. Follow the same method when you use scavenged nichrome wire from an appliance.

Connect one end of the wire to the positive output of the solar panel or test station, and the other to the negative output, forming an electric circuit. The polarity doesn’t matter.

Turn the power on, read the amperage and wattage values on your watt meter, and turn it off immediately afterward. Be careful when connecting the wire; make sure it doesn’t touch itself, as this would create a shorter circuit for the electricity. Your measurement will be inaccurate, but it will also draw a lot more current (A) and heat much faster, which can be dangerous. Make sure you don’t touch it either because it gets very hot.

Doing this, we measured 31W at 1.76A and 18V. Based on Ohm’s Law, we calculated that 18 V / 1.76 A = 10.2 Ω. Consequently, our wire has a resistance of 10.2 Ω/m rather than 8.71 Ω/m. That means that it should have a length of 31.7 cm to have a resistance value of 3.24 Ω:

(100 * 3.24) / 10.2 = 31.7 cm.

Image: Testing the first two solar oven prototypes with a grid-powered test station. Photo by Marie Verdeil.

Doubling or tripling the cable

However, it’s still too early to cut the nichrome wire to size. Depending on the wire’s resistive value that you are starting with, the length that results from your calculation may not be the most practical length for spreading the heat evenly across the surface of your heating or cooking appliance.

For example, the bottom part of our solar oven chamber, right above the electric resistance heating element, measures 26x33 centimeters. With a circuit less than 32 cm long, it’s impossible to heat the oven chamber evenly. A short wire would also create a very warm spot in the mortar and damage it.

This can be solved by connecting two or more nichrome wires in parallel. If you double the circuit, each wire should be twice as long (63,4 cm each in our case) to keep the same resistance value. If you triple the circuit, each wire should be three times as long (95,1 cm each), and so on.

This may feel counterintuitive, but the longer a cable is, the higher its resistance becomes: electrons will have more difficulty travelling through it. When you double the nichrome cicuit by creating two parallel wires, the electrons can flow in two circuits simultaneously, which means the resitance is halved. Therefore, to keep the same resistance value of 3.24 ohm, you have to make this double circuit twice as long. The same logic applies to a triple wires, where you have to make the circuit three times as long.

Image: Showing different layouts for the nichrome circuit, using one, two, or three cables in parallel. They are all equivalent in resistance. Illustration by Marie Verdeil.

Cut the nichrome wire to size

Once you have decided on the number of nichrome circuits, cut the wires to size. However, before you do that, add about 4 cm to every wire. You will need this extra length to solder the nichrome wire to the heat-resistant electric cables (see further).

Coiling the wire

Image: Coiling the wire around a screwdriver. Illustration by Marie Verdeil.

Doubling the circuit, as we did in our solar oven, quadruples the total circuit length. That turns one problem (a too-short cable) into another one (too-long cables). However, it can be solved by coiling the wire, which has an additional advantage: The thin nichrome wire becomes much easier to handle and bend when it’s coiled like a spring. You can do this by wrapping it tightly around a rod-shaped object, such as a pen or a screwdriver. Next, you pull the wire to extend it slightly again.

Thermal switch and fuse

An electric resistance heating element needs a safety precaution to prevent overheating, which could become a fire hazard or crack the mortar enclosure. If the heating element is connected to a solar panel without a battery, as is the case for our solar oven, you could argue that it already has a safety precaution: the sun sets every evening, cutting off the power source to the heating element.

However, if you also want to run the cooking appliance on a battery or with a grid-powered test station, you should add a safety precaution that cuts off the heating element if you forget to turn it off.

One way to do that is to add a timer switch. That is a component that controls an electric switch and turns it off after a predetermined time has elapsed. The second approach, which we chose, is to add a thermal switch and a thermal fuse. These components disconnect the circuit when the heating element reaches a certain temperature.

The thermal switch cuts off the heating circuit when its temperature reaches the rated temperature, and turns it back on when the temperature drops below a slightly lower value. The thermal fuse is an extra safety measure: it’s a single-use fuse that blows when it reaches its rated temperature. The thermal fuse should have a higher value than the thermal switch. You embed it in the cement layer, and once it blows, it’s impossible to replace without breaking the oven.

Image: The thermal switch and fuse on a first layer of mortar in our third solar oven prototype. Photo by Marie Verdeil.

We selected a switch with a maximum temperature rating of 200°C (392°F) and a fuse with a maximum temperature rating of 240°C (464°F). Note that the temperature measured inside the oven chamber will be lower than the temperature of the electric heating element. For example, our thermal switch turns off the circuit at 200°C when the oven chamber is around 120°C (248°F).

You can choose a thermal switch and fuse with a higher temperature. However, we cannot guarantee that the structural materials we used for our oven can withstand higher temperatures than those we use.

Connect the thermal switch and the thermal fuse in series (one after the other) between the nichrome circuit and the positive heat-resistant wire (the one that connects to the positive wire of the solar panel). Ensure the fuse and switch are embedded in the mortar to obtain an accurate temperature reading. Both switch and fuse have no polarity, which means you can connect their pins in either direction.

Solder the nichrome wires to the electric cables

Once the nichrome circuit is cut and coiled, you need to connect it to the electric cables from the solar PV panel. However, you cannot simply solder one to the other: the nichrome wires get hot and would burn the plastic casing of the electric cables. To prevent that, you need to install a pair of heat-resistant electric cables in between.

First, you solder the nichrome wire to the heat-resistance cable. If you want to add a switch and/or fuse (see above), it should go in between the heat-resistant cable and the nichrome wire. Then, you connect the heat-resistant cables to normal electric cables or directly to the solar panel cables (using any type of connector). You also want to put an on-off switch in the positive wire.

In summary, the circuit components should be connected in the following order: positive PV cable, on/off switch, heat-resistant cable, (optional) thermal switch, (optional) thermal fuse, and nichrome circuit.

Image: Soldering the nichrome wire to the heat-resistant electric cable. Step by step instructions. Illustration by Marie Verdeil.

Soldering the nichrome wire to the heat-resistant electric cable is a bit complicated because the nichrome doesn’t stick with tin solder. However, you can get around that problem. Start by applying tin to your stripped heat-resistant electric cable strand (fig2.). Then, coil a few centimeters of the nichrome wire around the cable ends (these are the extra centimeters you added before cutting the nichrome wire to size) (fig 3.). Next, apply a generous amount of tin on top of the twisted wire to trap it onto the cable (fig4.).

Electric cables come in different thicknesses, measured in mm² in Europe or AWG in the US. The higher the current that flows through it, the thicker an electric cable needs to be. Our circuit works at 5.555A, which requires a 1.5 mm² core wire area. The US equivalent is 16 or 14 AWG. Both the heat-resistant wire and the standard electric cable should follow this size requirement. If you have a different current draw, refer to the chart below to determine the required size. If you plan to use a very long cable between the solar panel and the cooking device, choose a thicker cable.

Image: Chart for AWG vs. mm2 sizes

Encapsulating the heating element

Once the electric resistance heating element is ready, it needs to be encapsulated in mortar, a heat-resistant material with high thermal inertia. We describe two methods for doing that.

1. Encapsulte the heating element in the device itself

The first method involves encapsulating the nichrome circuit within the structure of a specific cooking or heating appliance. That is how our electric solar oven works: the heating element is embedded into a layer of mortar at the bottom of the cooker, between the insulation layer and the oven chamber (where the food goes). See the manual for the construction steps.

Image: Electric resistance in a mortar bed. Photo by Marie Verdeil.

2. Encapsulate the heating element in a removable heat brick

The second method yields a tiled heating brick that can be inserted into various cooking appliances. In this case, the nichrome circuit is embedded in construction mortar and sandwiched between two identical tiles. The two heat-resistant electric cables protrude from one side, ready to be connected to a solar panel. It’s essential to use somewhat thicker and stronger tiles for this purpose, for example, terracotta floor or roof tiles. Thinner tiles may shatter due to the heat.

Image: A removable heat brick at the bottom of our second solar oven prototype. Photo by Marie Verdeil.

We use these removable heating bricks to power the first two solar oven prototypes that we made. It’s a less energy-efficient method, but if the nichrome circuit breaks, you don’t need to rebuild the entire cooking device.

The Living Energy Farm, which inspired the building of our own resistance heating elements, casts the nichrome circuit into a metal shell that they make themselves using sheet metal. However, in contrast to a tiled heating brick, a sheet metal casing requires skills and tools that are not so common. ²

Image: The electric resistance heating circuit embedded in mortar and sandwiched between two tiles. Photo by Marie Verdeil.

Assembly of the heating brick

Image: How to build an electric resistance heating brick from scratch, step-by-step instructions. Photo by Marie Verdeil.

fig 1-2. Place one of the tiles with the back side facing up, apply a dollop of mortar, and flatten it across the tile, almost to the edges.
fig 3. Place the electric resistance circuit on top of the mortar. Make sure the wires don’t touch or cross, as this would create a short circuit. Try to evenly distribute the wire across the surface to distribute the heat evenly, but avoid the edges to prevent the nichrome wire from sticking out. Leave at least 3-5 cm of heat-resistant electric wire protruding from the tile on one side, so that you can solder or otherwise connect it to a standard electrical cable.
fig 4-6. Add a little bit of mortar on the other tile and press it on top of the other like a sandwich. Leave it to dry out for at least 48 hours.

Setting up a test station for electric heating resistance heaters

A test station is convenient for testing resistance heating elements designed to operate on solar panels. Such a test station consists of a DC power supply and a buck or boost converter. It allows you to simulate the solar panel’s power output using grid power. A test station also serves to measure the precise resistance value of 1m of nichrome wire.

A 12V or 24V DC power supply converts 110/220-240V AC power into DC power, comparable to the electricity produced by a solar panel. Choose one with a capacity of at least the power output of your solar panel (100W in our case). If you connect a buck or boost converter to it, you can manipulate the 12V or 24V output voltage into a higher or a lower voltage. Since our heating resistance runs on a solar panel without a battery or charge controller (Vmax = 18V), you can match the buck or boost converter to an output of 18V.

Image: Setting up a test station, using a DC power supply (left) or a laptop adapter (right). Illustration by Marie Verdeil.

To wire it, connect a + and - cable to the DC supply into the buck or boost converter. Use a boost converter to step up the voltage from a DC supply below 18V, or a buck converter to lower he voltage drom a 24V power supply.

If you build an electric heating resistance that you want to run on a 12V or 24V battery, you only need the DC power supply (with a voltage output of 12 or 24V, respectively).

If you are short on cash, you can use a laptop adapter instead of a DC power supply. The DC output of a laptop adapter is printed on the adapter itself. It’s typically around 70-90W at 19-20V. While it won’t be able to power a 100W solar cooker at full strength, it’s suitable for testing the circuit, and you can obtain it for free. If you have a lot of money, you can also purchase an adjustable lab DC supply, which allows you to adjust the voltage and current outputs using knobs.

Other types of power sources

In case you want to build a heating element that runs on a 12V or 24V battery and solar charge controller, the voltage value for your calculation is 12V or 24V, respectively. The current depends on the wattage that you want to achieve. For example, if you have a 12V power source and you want a 100W heating element, you need 8.33A. If you have a 24V power source and you want a 100W heating element, you need 4.17A.

Image: Chart of common power sources with their power ratings and the resistance value needed to make the heating element work at full power.

A different style of DIY heating resistance uses diodes, connected in series, as an alternative to electric resistance wire. Find more information in this paper ↩︎
One way around this is to use an existing metal cookie box or a large tin can bottom, but in that case, you’re stuck with the dimensions of what you can find. A metal box conducts electricity, so make sure the electric resistance wire doesn’t touch the metal. You can also pour the mortar into a plastic container and remove it once the mortar has cured. ↩︎

How to Mount a Balcony Awning

Wed, 09 Jul 2025 00:00:00 +0000

Hi Kris,

I’ve been reading your website for quite a while. It’s one of my favourite blogs. Thank you for what you are doing!

We are currently experiencing a heat wave in Germany, so I drew inspiration from Low-tech Magazine’s article “How to Dress and Undress your Home” and built an awning on my balcony. I documented the process so that other readers can install one themselves.

The overall cost for my build was around 50 Euros, but you can do it much cheaper by using upcycled materials. It requires only a few tools to build, so almost anyone can reproduce it.

Required materials

Steel cable (or rope). I went with a 4 mm galvanized steel cable. I want the build to be sturdy and be able to withstand strong winds. A 3 mm cable would probably work as well. Warning: Some inexpensive steel cables have a plastic outer shell, which may reduce their strength due to the smaller diameter of the steel cable. For example, a 3mm cable would have a 2mm or 1.5mm steel core. You could also use rope instead of steel cable, which will be cheaper.
1 x turnbuckle
2 x cable thimbles
8 x cable clamps. There are different styles of clamps. The one I’ve chosen is also used in heavy construction.
1m petrol hose with 6mm inner diameter.
1m x 3m awning fabric. The distance between eyelets should be 50 cm.
7 carabiners. This number depends on the number of eyelets you have and the number of attachment points you will use.
Some paracord. It comes with the awning fabric, and I have no idea how long it was.

Image: Required materials. Photo: Dmitriy Kurochkin.

Required tools

Wrench or spanner for cable clamps
Something to cut the steel cable. Here are some options:

Metal chisel and hammer
Cable cutter
Hacksaw
Angle grinder
Hardware shops will cut the cable to the desired length

Source links

Building steps

Measuring

Image: The south-facing balcony. Photo: Dmitriy Kurochkin.

The required cable length is the distance between the posts plus one or one and a half meters. It’s better to have a little more cable than you need. It’s easy to cut extra wires, but it isn’t very easy to join cables if you don’t have enough. In my case, the distance is 3.8 m, and I used just under 5 m of cable.

Prepare the cable

The upper support for the awning consists of two pieces. The shorter piece is attached to the left post and has an eyelet. The longer piece is fixed to the right post and has a turnbuckle attached to the other end.

Tip: Wrap the area where you plan to cut the cable with electrical tape to prevent fraying. See this video.

The images below illustrate an example of how to use a thimble and cable clamps to secure the turnbuckle. You are probably fine using just one clamp, but for safety, I opted for two clamps. You should tighten the clamps very well until you see some deformation on the cable. Always place the loaded end of the wire on the base of the clamp and the free end on top of it.

The image at the bottom shows how the shorter piece of cable should look before the installation. The hose has two functions. It prevents damage to the posts and provides a perfect grip to avoid slipping. The image in the top right corner shows how the turnbuckle is attached to the longer piece of cable.

Image: Preparing the cable. Photo: Dmitriy Kurochkin.

At this point, I finished all the preparations I could do inside the house.

Assembling

Now it’s time to move outside and start final assembling. When tightening the cable around the post, leave some slack. You should be able to adjust the cable up and down to suit your needs later.

You need to unscrew the turnbuckle fully. There should be no tension on the cable between the posts. You should be able to get the hook on and off easily. Now, you are ready to position it as desired. Use the turnbuckle to put tension on the cable.

Image: Tightening the cable around the post. Photo: Dmitriy Kurochkin.

Fasten the fabric

Use carabiners on every top eyelet. You can use carabiners or rope to secure the bottom of the fabric to the railings.

Image: Fastening the fabric. Photo: Dmitriy Kurochkin.

Final result

I’m happy with the outcome. I can finally spend time on my balcony, even on sunny days. There was way too much sun in the summer as my balcony faced south.

Image: The mounted awning. Photo: Dmitriy Kurochkin.

Image: The folded awning. Photo: Dmitriy Kurochkin.

Image: The mounted awning. Photo: Dmitriy Kurochkin.

Retrospective

What went well?

Excellent protection from the sun, and I saved quite some money
The choice of materials was quite good in terms of quality
It’s easy to operate. It takes less than 30 seconds to fold and unfold it.
The build is very sturdy and can withstand wind. It handles medium-strength wind without any issues. I’m waiting for a strong wind to test.

What can be improved?

I purchased an awning fabric that was slightly too small. It would be better to have a 1.5m x 3m area. I had to experiment to find the best position for the awning.
I have some leftover hardware, including hose clamps and turnbuckles. I could save some money by buying everything separately in the local shop.
I’m still thinking about how to fasten the bottom of the fabric in a better way. An elastic cord might be a good option.

Wall and ceiling mounts

If you don’t have a post to attach the cable, your only option is to attach the cable to the wall or ceiling. Wall and ceiling mounts come in many different forms and shapes. It should be able to handle at least 100 kg, as wind gusts might be pretty intense. Generally, the stronger it is, the better. It uses screws and dowels to attach to the wall. It will require tools for drilling, such as a hammer drill and a drill bit suitable for the type of wall material being used.

You can use the keywords “ceiling hook,” “hanging chair mount,” or “eyelet plate” to find it online.

Below is an example of a complete set from the Toldoro manufacturer.

Image: Ceiling hooks.

Safety precautions

Learn how to safely use all tools before starting. Read manuals or watch quick guides if needed.

Wear gloves when handling steel cables. Frayed ends can cause cuts or puncture wounds on your skin.

Use a stable stepladder for installing upper lines. Place it on flat ground and don’t overreach. Consider having someone nearby to assist.