Heating systems for new home

[Slickcraft]

Originally Posted by FlyingScot

I have never had mini splits in the same home as oil, so unable to do a direct comparison, but I am confused by your math or maybe by terminology. If mini splits are, say, 30% (or more) more efficient than oil, and they are operating at 85% efficiency at -13, aren't they still more efficient than oil at that temp? Thanks

The math is straightforward. At minus 15 deg 85% efficient means 100 watts in gets only 85 watts of heat out. Over 0 deg temp the efficiency is over 100% so the heat pump puts out more watts than what is required to run the unit.

The above has nothing to do with comparison with oil heat. That said, the advantage over oil is temp dependent and numbers like 30% are on average. At 10 below zero best to run the oil burner.

Alan