The tower cottage is heated and cooled with a ductless split heat pump. I have no idea how it works, despite the fact that it’s been explained to me. But maybe you’ll understand when Buzz explains it to you!
The hot water heater is a heat pump at the Summer House. Although there is no heat pump for heating and cooling, the windows open up to take advantage of the near constant breezes on the hilltop. Shade trees and the roof overhang also help cool the interior, and many fans can be moved to provide focused cooling on hot days. The wood used to take the chill off on cool days is a renewable resource from local managed wood lots.