What do you use for heating water? I'm tempted to switch to mini-split heat pumps for heating, but I'd also like to have hot water. My house is very small and there's basically no room a big hot water tank.
I have a heat pump (Fujitsu Waterstage) that does central heating via hydronic radiators and can also heat hot water. Annual heating costs are a lot lower than when we had oil based heating. You can also just get hot water heat pumps that are basically heat pumps integrated into a big tank of water.