I really like solar ovens. When I think about how much power a regular oven or stove top uses, it blows me away. At 3,000 watts for the oven and about 1,500 watts per burner, then you could easily be using up to 9,000 watts while cooking a large dinner. Or even 4,500 to 6,000 watts typically. But, the sun is free! How amazing is that? A solar oven at about the size in the videos below has about 4 square feet of glazing. At 50% efficiency, then that means about 250 watts of consistent power. Pretty much like running a big crockpot all day, for free.
Here are a couple of videos showing a homemade solar oven in action.
Notice that this solar oven has 2 layers of plate glass, but it is just laying on top and not sealed. But even still, it works great.