Julie Hambleton

Julie Hambleton

November 4, 2020

Window Box Solar Heater That Gives “Free Heat” All Winter & Doubles As A Solar Oven

Imagine if you could heat your home and cook a meal completely for free, no electricity or gas costs required. With this window box solar heater, both of those dreams can become reality. 

Window Box Solar Heater and Oven

This window box solar heater is essentially like a mini-greenhouse that you attach to your window. The addition of a few small fans then pushes the heat right into your home and can heat up a room remarkably effectively. 

If that wasn’t good enough, the fans can be removed, the window can be closed, and the window box solar heater becomes an oven where you can cook just like in a regular gas or electric version.

How the Window Box Solar Heater Works

On her YouTube channel FrugalGreenGirl explains how she built her solar box out of leftover panels from the greenhouse she had previously built. She then attached it to the outside of the window.

An important thing to note is that she had to remove the screen from the window because the box heater got so hot that it began burning the screen.

To the top of the box on the inside, she attached three small solar fans to help circulate the warm air from the box throughout the room. Next, she added a sunshade that is painted black on one side and shiny metallic on the other. For the heater, she keeps it black side facing upward to absorb more heat.

Thanks to the fans also being solar-powered, this window box solar heater can function completely off-grid, making it ideal for off-grid living or just as a backup if your power fails.

How it Works As An Oven

Making the window box solar heater function as an oven is quite simple. To do so, you:

  • Remove the fans
  • Flip the sunshade so the shiny side faces upwards
  • Close the window

You will want to purchase a small solar oven thermometer so that you can ensure it is reaching appropriate temperatures to cook your food. She also suggests using black cookware with thin walls as opposed to stainless steel for more optimal heat transfer.

Lastly, she always uses a food thermometer to make sure that her food is cooking at a safe temperature and that things are done as they should be before eating them.

Read: The Quick and Easy DIY Way to Turn a Fan into an Air Conditioner

Other Versions of the Window Box Solar Heater 

Window box solar heaters don’t have to be made from greenhouse panels. You can also make them using wood and glass.

With this version, it is important to paint both the interior and exterior of the box with a matt black paint. If you use glossy paint it will reflect sun rather than absorb it, even though it’s still black.

A pain of glass is used to allow the sun in and also trap the heat. This version includes a mirror on the underside of the lid that can be propped open to deflect even more sunlight into the box. This lid also allows for the box to be closed and not absorb any heat when you don’t want it in the summertime.

The box is built on an angle tilting upward toward the window so that the heat in the box will naturally travel in that direction (because hot air rises). The hot air then travels through holes drilled into the end to heat up the room on the other side.

Solar Heat Made Simple

No matter which window box solar heater you choose to make, one thing is guaranteed: It will help you save money and energy. So why not make your home a little greener, especially if it will make your wallet a little fatter in the process?

Keep Reading: These 5 Hacks Will Lower Your Energy Bills