If you have more details I'd certainly appreciate it. We're running a now 25 yr old whole house forced air system - 4 ton. Fuzzy memory but as I recall it pro

If you have more details I'd certainly appreciate it. We're running a now 25 yr old whole house forced air system - 4 ton. Fuzzy memory but as I recall it probably has a CoP of around 16 with defrost cycles when the temp goes below +5C. It has been mostly maintenance free for those 25 years excepting on time when it started icing up - needed a recharge of refrigerant as it seemed to be a bit low - tech figured a slow leak somewhere but never found it. The system works fine and my best guess is that it is somewhere around 3:1 in favour of heat pump over resistive heat (electric baseboard or radiant panels).