The last two nights have been very similar, preceeded by sunny days with lots of solar gain, around 85%RH and dropping to freezing or just under. So I decided to compare quiet mode off vs most quiet. I enabled most quiet at around 5pm yesterday.
On the left, is normal operation, on the right is quiet mode set to ‘most quiet’.
https://emoncms.org/app/view?name=MyHeatpump&readkey=f2befde7239c2ce2e9db254e66706870
The big difference appears to be the number of defrosts and run time between them.
COP appears to be the same, if you pick 4am to 8am, it comes out at 2.2.
Mean input power is 1.5kw vs 1.7kw
Mean heat output is 3.5kw vs 3.7kw
Defrosts 4 vs 7
It looks like ‘most quiet’ isn’t performing as well but the numbers say it’s about the same.
I’ll probably switch back to quiet mode off since it doesn’t disturb me at night anyway (despite being under our first floor bedroom window).