I thought I’d try again following @Timbones pointing out the Heat Geek link.
I’ve opened all the radiators fully and it’s a bit cold ( 7.0 °C ).
It’s going pretty badly. I started the experiment at 17:30.
You can see beforehand the efficiency was better. It was actually 373% with a flow temp of 37.0 °C.
With the system being wide-open it was 304% with a flow temp of 34 °C. We can see the cycling because the heat pump can’t modulate down far enough.
It averaged 1.54kW of input power over those three hours versus the 1.20kW input power yesterday when the conditions were similar. For those three hours:
Yesterday: Space Heating 327%, £0.52 (kWh: 3.6 => 11.8, kW: 1.20 => 3.93)
Today: Space Heating 304%, £0.67 (kWh: 4.6 => 14.0, kW: 1.54 => 4.67)
This re-confirms earlier observations that I use quite a bit more power (28% in this case) when I try to keep things running continuously.
The indoor temp has gone up from 21.5 °C to 23.5 °C. It really is too hot. Now, I’m not making the next bit up. After an hour we had supper and when the kids arrived they both said they were cold without prompting. It was insane. I think it’s because they were going round without socks for example, so the higher indoor temp was putting them in a “I don’t know how to handle this” situation.
I can’t keep doing this experiment, it’s too hot in here.