You can build you own, but it requries some diy skills. But tell me, how do these tubes work? because solar power is based on the sun, not if its cold or hot. Yes, when there is sun it is generally hotter.
Other great green projects are wind panels or hydro power. It all depends on the area where you live and which is in abundance
[URL="http://www.home-improving.com/847/48-easy-home-remodel-project-to-increase-home-value//"]48 Easy and Fun DIY Project [/URL]