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Pretty sure mini splits are significantly more efficient today, with SCOP of above 5, so that seems unlikely?

This unit runs at about 5

I recently replaced my [central, ducted] heat pump, and the new one is rated with a 4.981 SCOP. It's fairly efficient, but not the most efficient on the market.

-40% for the duct heat loss

That seems kind of high for insulated ducts, where does that number com from?

US energy.gov

It would be nice to actually link the source[1] (PDF).

The stat is that you lose between 25-40% efficiency for "typical" existing installations. The document goes on to explain that an insulated duct which doesn't leak doesn't have this kind of efficiency loss.

[1] https://www.google.com/url?q=https://www1.eere.energy.gov/bu...

700W for the gas ducted heater fan. That’s the steady state energy consumption of all 3 units heat pumps running simultaneously. This is a small house of 100 square metres/1100 square feet.

Obviously a new EC fan will be more efficient than a 20 year old AC fan, but I’m talking about a retrofit application here.