The catch-22 of solar roofed cars is the time of year when they are likely to be most useful—during the summer—the last thing you want to do is park your car in the sun to charge. Whatever benefit you gain from solar charging, you lose as soon as you have to fire up the AC for 10 minutes to make it livable.

In general, it’s a good idea to park your car under cover for a lot of reasons. Fabrics don’t do well when exposed to the high heat you get parking in the sun for prolonged periods. If you live or work in a city, chances are high that you are parking in a covered garage or basement.

Solar roofs on cars are a neat idea, but not likely near as useful for most people as spending the money on more batteries for longer range.