MTD 
Solar Heated Hot Tub

This easy to build, low cost, solar heated shed might be used to keep a hot tub hot. You probably can't see the hot tub because it's not part of the animation, but it's there or, at least it could be there. The five tanks of solar heated water are used to transfer heat to the tub, year round. Of course there will be some sunless days, but four hours of direct sunlight on six MTD collectors should harvest more than 80,000 BTU's. What would you use a solar heated space like this for?

MTD Solar Heating    book    +    Sun Heat & Solar Plumbing CDs   $75   (shipping included)