Yeah my winters can get very extreme, so much so that the amount if heat from a rocket stuff puts out too much co2 to keep safely inside and so it has to be exhausted. Which to me is a double waste. I was just thinking a heat pump on the heat exchanger might be a good idea, but if it could powered by the last of waste heat it might really be worth it.

The heat pump is probally inevitable though because again the co2 level just being a waste.