Very helpful. Thanks for sharing Graham.

well intentioned but ill conceived…just keeping the cost of heat pumps high!

From my own experience of GHG, I can see a lot of installers just slapping up to £5k on the price.  A couple of things I would do to stop this: 

- restrict the scheme to use of ASHPs and other hardware where manufacturers/importers publish real prices online

- requirement for detailed quotes that separate out hardware and labour

- vetting by MCS of quotes for 'reasonableness'

My GHG was for loft insulation so at least is was easy to work out how much the installers were ripping off the scheme (they doubled the price but I got it for a third so I was happy-ish)  

I don't see this working very well either. In many, maybe even most, installations, the rads will need upgrading, because the scheme requires the ASHP retrofit to replace a fossil fuel boiler, and the rads will be fossil fuel sized, and too small for an ASHP, or if replacing electric storgae heaters they will need both rads and all the associated pipework etc. This sort of installation is going to cost £10,000 upwards, so the homeowner will be £5,000 upwards out of pocket, assuming they have that sort of amount of cash lying around. They will then get MCS approved quotes that say they don't needs new rads (of my four MCS quotes, two said I didn't need the rads upgraded) and so can save several thousands pounds, which naturally they will do, and so get a system that fails to heat their home adequately. Some will realise they need new rads, and will either swallow the cost, others will decide to stick with fossil fuels for the time being. I also agree with @kev-m, without very transparent pricing, and someone to check quotes, there are very strong incentives for installers to inflate prices with these types of scheme.   

Posted by: @grahamh

On 31^st March 2022 the RHI grant for heat pumps ends, the new Heat pump grant scheme starts on 23^rd May 2022

Why a nearly 2-month gap?

Posted by: @grahamh

The performance of the heat pump is not taken into consideration for the BUS, only efficient systems will get through, but the hurdle of efficiency is very low COP of 2.8. No one makes a heat pump that poor anymore.

Is that published book COP (or SCOP?) or as-installed COP? I'm sure we've seen a few installations on these forums and others which would struggle to achieve 2.8 even on a mild sunny day thanks to badly-sited external units, buffer tanks and fixed high flow temperatures controlled by on/off thermostats.

@mjr it’s taking a long time for the penny to drop about on-off thermostats!

At the moment tenants have no absolutely rights when it comes to issues with their heat pumps as they do not own the pump so at least if they have bought/contributed to the system themselves they would it seems, but what would happen if their landlord wanted the house back? I can also see how this scheme might drive up standards regarding installation but I do also agree with @mjr re the COP, mine struggles to get anywhere near the published COP, even in September. Mine has a buffer vessel and is a high temp system which I'm also not happy about as I have UFH and radiators sized for a low/standard temp system in a well-insulated new build. I was literally crying over my fuel bill BEFORE the price rise.

@saz went don't you just lower the flow temperature?

If it's not something I can do using the basic controller then I'm not permitted to do it myself via the installer menu. I asked the last engineer that was here to alter it to 45 degrees for the heating but my rads are still hot and the UFH has hot spots. I know the UFH runs most efficiently on lower temps, rads may need slightly higher (but I do have large Stelrad K2) but my consumption is still an issue. I have already asked for the heat curve to be lowered once also. Wierdly The flow temp from my UFH is lower than the return also, even shortly after it clicks on before room up to temp. This heat pump can manage the legionella cycle w/o the use of an immersion but the immersion is still wired into it. So many questions! Very little answers. Meters pick up what? when no heat or hot water being called for.

Tenants should have the right to have their systems optimised for them so that they can live in comfort but in the most efficient way possible. We may not own the pump, but we are the bill payers. In my opinion ASHP's need alot of tweaking after install, and we should have the right to alter certain settings to suit our needs without compromising anything. Is it not well known that high temp systems are less efficient for new builds? My system has had endless leaks and pressure drops also. It has been a nightmare for me and I actually want to be positive about ASHP's but am finding it very difficult at the moment.

@mjr i have no idea, ask Ofgem, im just telling you how its going to work. Ofgem know all the answers