@szescstopni after 3 years of wood burning - not the best idea. It's either too hot or too cold, storage is a big issue, you have to bring it home and it's heavy, it's hard to keep it dry and it's just sad to destroy the trees.
My dream is a ground heat pump powered from PV, but that's probably most expensive option.
Mad scientist way would be to build DIY heat pump out of old fridge, tho not sure how well would that work in real life.
@jaks I'll keep a small wood stove for emergencies, hoping to never use it. Ground source would be the best