After looking at all the photos they may be using fire place for heat. There are also solar panels that may be used provide a heated fluid to the floors, weather permitting and a boiler as backup. There may be no cooling needed based on the geographical location. I believe this house is located in Ontario, Canada. The photos do not provide much info.

The house has radiant heating but no air-conditioning , it's a cottage on Georgian Bay, so lots of wind for ventilation.