Great Canadian tech...
Cansolair has developed a forced convection solar heating unit called the Model RA 240 SOLAR MAX. A dwelling of 1000 square feet can have a complete air change in 1.5 hours. Working experience indicates that comfortable room temperature can be maintained in a 1000 square foot dwelling with 15 minutes of sunlight per hour.
The price?
$2695.00 + shipping and taxes where applicable