The heat pump is too big.
I need just over 4kW at worst.
The 9kW puts out 4kW all of the time, it is too much.
I don’t think any other explanation is required!
We had a government grant here, the installer says what i must have based on the heat loss they calculated.
They calculated 7.5kW, it’s 4kW as I told them. They have to replace it with more suitable unit.
It will be replaced with an 8kw Daikin, if I am right I don’t expect to be discussing COPs of 4 or 5.
I don’t expect any trouble with the 8kW, it is more than enough for this house.
If I need to I can shut the conservatory and then my heat loss is only 3kW at -4c, I am sure we will be OK.
I currently have an EDLA09E3V3 installed in June 2023.
Daikin does report energy consumption and heat produced but there are two problems. It is not very granular, it is difficult if not impossible to diagnose issues.
The second problem is that the measurements are not guaranteed to be accurate, certified heat and electricity meters are accurate and the only true way to measure performance, anything else is unreliable. This is my opinion and others may not agree but I don’t care, I want to know with absolute certainty, anything else for me is guessing, it may be educated or informed guessing but nothing beats accurate measurement.
I can run continuously as you have seen.
There are things you don’t know though, the flow temperature rises because I allow it to, I can stop that, I would get less heat though. I let it increase by setting an overshoot of 4c on the set flow temperature. It maintains the biggest dT it can and produces more heat for the same electricity.
I am a petty and sad man who likes to see a good COP, I could have less heat and a more comfortable life at less COP, but I choose not to.
My problem is that I could do all of this more efficiently, more comfortably and with less electricity than I currently do.
For all those reasons this heat pump needs to go, I will get the same result for half the electricity with the 8kW.
The 8kW turns down to about 280w of electricity and for this I will get 2,000w of heat, much better than the 900w of electricity and 4,000w of heat I get now.
Also, as I run from batteries most of the time, less electricity consumption helps a lot, 600w doesn’t sound like much but it can often be the difference between importing or remaining 100% on batteries.
I pay nothing for electricity as I export far more than I import.
I get paid 15p to 20p per kWh of export and pay about 20p per kWh on average for what I import.
I export more than 6,000kWh of electricity a year which gives me about £1,200 of income.
When the sun doesn’t shine enough I have to buy electricity but the cost in a year is less than the £1,200 I get paid.
Therefore I pay nothing each year.
I haven’t worked out the exact figures but I am still £700 in credit with my supplier. I expect one more bill of about £150 in a weeks time and then most of my electricity comes from the sun.
The heat pump either runs from the sun or my batteries. Even if there is a less sunny day we are at the point where my batteries can cover a couple of days and I will get it back from the sun. I expect to import very little by the end of the month.
My profit for the year from solar panels should be £450 to £500. With a heat pump that uses between 50% and 70% of what I use now this should become even more comfortable. I hope I never buy electricity again in the course of a whole year.
In the summer I export around 1,500kWh in the best months, some days I generate over 80kWh of electricity.
And before you or anybody else wants to point it out, I do know that I had to buy the solar panels and batteries, not something I am going to forget for a while!
