Thermal insulation helps to decouple indoor climate from the outdoor climate. It depends a bit on what kind of heat period you consider. When high ambient tempe

Thermal insulation helps to decouple indoor climate from the outdoor climate. It depends a bit on what kind of heat period you consider. When high ambient temperatures occur it will remain cool for longer indoor and night ventilation can be used to cool the house. The cold produced by the AC is also better trapped inside, ie used more effectively. There has been a case of extended power outage in Germany due to heavy snowfall. I saw a report that showed how the indoor temperature remained almost constant for the first two days of the outage.