Home Made Passive Solar Thermal Furnace Heats House for Free

Home Made Passive Solar Thermal Furnace

Home Made Passive Thermal Furnace ( Thermal Magazine) – Even if you live in a part of the world where you have relatively cold winters, passive thermal heating can provide free heat for your home if you apply it in the right way. In this how-to video you will see how to build a passive furnace with the simplest of material for less than $ 50.  

The science is relatively easy to understand. You take the colder denser air from your house and pass it though the outdoor passive solar furnace which is a large diameter flexible air duct arranged in a cabinet with a transparent front cover.

The solar furnace should face the rising sun so that you get the impact of the suns ray when you need it to heat the house.

The suns rays are absorbed by the black painted duct and transferred to the air inside, heating it and causing to expand. This natural convection action provides the force to move the now warm air into the large inlet duct and into the house where you need it.

And there you have it. Free solar heating!

About Gordon Smith
Gordon's expertise in the area of industrial energy efficiency and alternative energy. He is an experienced electrical engineer with a Masters degree in Alternative Energy technology. He is the co-founder of several renewable energy media sites including Solar Thermal Magazine.


  • Would it be just as effective to cut a new Window of the same size and let the sun shine directly into the house?

  • Dave says:

    Because the window is partly open, air would come through that from outside.

    Nice idea, why don’t you put the hose through the wall though?

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