DIY Homemade Solar Furnace -- Solar energy is free, and is always begging us to make use of it. Here is another great way you could make use of solar in your house. Why not build this diy homemade solar furnace to help heat your home this winter. Most of the materials for this project can be re-purposed or picked up at dump yards. The reminder should not cost you more than $50 at your local hardware store.