Cost: $300 (attic insulation), $23 per 4' x 8' board (solar sheathing), $4,000 (new roof), $600 (whole-house fan), $570 (whole-house heater), $1,450 (two skylights) After $18,500 in rebates and ...

space-based solar stations enjoy energy density that’s 10 times greater than what you might get from the roof-mounted solar panels on your house because the sunlight in space is that much more ...