Well, even if you assume 100% reliable supply of whatever kind of energy (gas, power etc.) your system needs, the heating device can still fail. Having some ki

Well, even if you assume 100% reliable supply of whatever kind of energy (gas, power etc.) your system needs, the heating device can still fail. Having some kind of backup in places where it can get really cold is always a good thing IMO even if it is just for one or two rooms