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Old 02-03-2023, 09:44 AM   #113
FlyingScot
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Quote:
Originally Posted by Slickcraft View Post
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
Yes, this is why I am confused. I understand that a minisplit on warmer days is better than a minisplit on colder days. But the question is whether a minisplit on colder days is better than oil on colder days. If a minisplit is 30% better than oil in general, and oil is assumed to be always at 100% of its own efficiency, then doesn't the minisplit need to fall to 70% efficiency before oil is equal, and 69% before oil is more efficient? If all of this is the case, then the minisplit on a -13 day at 85% is still the best choice
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