Your final point misses the parent's point completely. Yes it uses energy, but cold areas use more. It might also be worth mentioning that the use of boilers ma

Your final point misses the parent's point completely. Yes it uses energy, but cold areas use more. It might also be worth mentioning that the use of boilers may be dirtier than going through a centralised burner, as the economies of scale would favour efficiency improvements at large scale more than at small, building scale. As for being unhealthy, that's an issue of dry, circulating air. This would be addressed better with radiative cooling and potentially humidity control. Some cleaning out of air filters may also be due. edit: Oh and of course, building regulations (and enforcement thereof) and insulation shouldn't be forgotten, like I just did.