@batpred As my installation survey was carried out under the HG assured warranty scheme, my installer didn’t get much say as to the size of the heat pump. What I can say is that with no radiator changes, the HG survey was looking at a 5kW Valliant with a SCOP of 3.7. I elected to go for some radiator changes based on running my boiler at 50C for past 2 years. These radiator changes increased the minimum SCOP to 4 based on a 7kW Valliant. My predicted heat loss is 5.9kW at -3C.

A month or so on my system has stabilised on a 0.2 heat curve with an internal temp of 19.7C. All radiators fully open in Weather Compensation mode manual with room temp mod ACTIVE. Yes, I do get HP cycling: 338 cycles with just over 200 hours of operation. Having the heat pump cutout temperature set at 14C seems to be working well. So far in May, the heat pump has consumed 50kWh of electricity to cover heating; hot water and cylinder disinfection. I don’t have heat pump monitoring but looking at a similar sized heat pump (SCOP4.5) in my location which does have live monitoring, my recorded performance is closely matching it - particularly in respect of flow temps; daily usage and costs.

Posted by: @l8again

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@batpred As my installation survey was carried out under the HG assured warranty scheme, my installer didn’t get much say as to the size of the heat pump. What I can say is that with no radiator changes, the HG survey was looking at a 5kW Valliant with a SCOP of 3.7. I elected to go for some radiator changes based on running my boiler at 50C for past 2 years. These radiator changes increased the minimum SCOP to 4 based on a 7kW Valliant. My predicted heat loss is 5.9kW at -3C.

Thanks, that's very useful to know. I believe us using -2C is due to being in the SE. 

We are still waiting for HG to come back to us on the specifics, hence we are self evaluating the pump modulation bands. 

Vaillant is our preference, but the pricing is hitting the tight budgetary constraint! And we will not postpone the rad upgrades.. 

@l8again 

It seems you did very well.

With our HG heat loss, we did not have anything proposed close to a SCOP of 4. Our heat loss is also outside the bands calculated based on 30 mins gas usage. 

Personally, I don't always rate the "payback on install" method for decision making.  For some it might be the ultimate test and that's fine. But I take a certain pleasure in having things done well. I don't like to compromise if I can help it, even if it looks a bit splashy financially. 

I think some people value the lower disruption service and they're giving you the option to have it or not. I don't think either way would be a bad decision. 

Three months on, I am getting the impression that my installer is no longer fully engaged with the Heat Geek model. This morning, one of his lads came out to repair 3 Primary Pro broken insulation joints. When I gently challenged him about the thin layer of Bond and Seal that I could see on the broken joints, the response was ‘we fit what Heat Geeks send out. We don’t use this type of insulation on our own installations’. The implication being that I got what I paid for.

The simple fact of the matter is that whatever insulation is used, the manufacturer will provide detailed installation instructions which in the case of Primary Pro includes lots of ‘Bond and Seal’. Fitted properly, Primary Pro gets very good reviews but I accept that from an installer’s point-of-view it is a time-consuming and messy installation process.