In Newfoundland, inventor Jim Meany has developed a forced convection solar heating unit that reuses aluminum cans as core heating elements in solar panels.
As the sun heats up the air inside the soda cans, painted black, a fan pushes cold air out of the house and lets the warmer air from the solar panel in through two dryer vents.
A dwelling of 1,000 square feet can have a complete air change in 1.5 hours. Comfortable room temperature can be maintained in a 1,000 square foot dwelling with 15 minutes of sunlight per hour.
His company Cansolair sells this unit, which is virtually maintenance free: you need no fuel, no insurance for parts.
It's a lifetime supply of free heat that pays for itself in 3-5 years... using recycled soda cans! Brilliant!