What is the cost from a non MCS certified installer - i.e. without the boiler upgrade scheme.

I would wait a bit. Partly to see how the BUS grant pans out.
Don't think installers are giving guarantees that all installs will qualify as yet.

How well insulated and airtight is the house?
For what reasons are you wanting to install an ASHP?

There was a humongous boom in ASHPs as people rushed to get theirs installed before the end of RHI in April, on top of the general boom on everything building related, and interest triggered by the energy price rises. The installers were off their feet and struggling to deliver the jobs they had priced.

The suppliers/distributers were announcing big price increases. Delivery on ASHPs was 12+ weeks, which is a problem as the BUS vouchers are only valid for 3 months and the installer is at risk if they cannot complete before the voucher runs out.

We were looking to get one installed last winter but have been messed about by the two reputable firms in our area, they spent a long time working on quotes, then jacked up the prices by several £k just before signature, and now are not returning calls. They don't need our business as their hands are full with jobs closer to base. The technical guy at one has gone off with long Covid and they are struggling without him, he does the heat loss calcs. The other would not do all the calcs until after we paid a deposit.

A number of non-MCS general plumbers and local electricians have announced they are now installing ASHPs, however they do not have the manufacturer's accreditation which brings the extended 5 or 7 years warranties, and they are at the back of the queue for purchasing the units. There is rather more to an ASHP than just hooking it up to power and water, so it is hard to be confident in which non-accredited installer to go with, although we do need those guys to move into the installer base.

We will wait and see if things calm down later in the year. Paradoxically, at current energy prices, it would actually be worthwhile for us to spend the £12-£18k prices, but who knows how long the current prices will continue for.

Thanks @WillInAberdeen. It's interesting to hear how prices rose when ASHP demand rose - I guess that is probably happening in my area right now.

Note that AIUI if you use a non-MCS installer then you won't get the grant. I believe the work has to comply with MCS-020 and that requires the installer to be an MCS Contractor (see 3.1.b)

BTW, a random website that I've heard of before - https://www.nu-heat.co.uk/renewables/air-source-heat-pumps/ - says: "You can expect a high-quality and well-designed air source heat pump system to cost from £5,000, with installation for a 250m2 property in the region of £11,500. This includes: ..."

edit: to add that if changing the radiators is a significant line item then it might be worth doing that yourself.

Inflation in this area seems to be running well above the general rate of ~10%pa so price benchmarks get quickly out of date.

On the plus side, VAT has recently been cut to 0% on ASHPs and all associated works if done in the same job - rads, cylinders, making good, etc. If those are done separately, you pay full VAT.


Replacing all our the rads added about 15% to the price, so not a big item. However the installers were keen to make sure they were done 'right' (in their view) because the rad and pipe sizing is closely linked to the ASHP capacity selection and efficiency calcs they have to do for MCS.

They were also very keen to renew the cylinder, pump, zone valves, expansion vessels, etc, to avoid any chance of getting called back to any fault within the 7 year warranty, despite the existing ones not being particularly old. This added probably another 15% of the price.

Then 40% of the price was the ASHP unit and buffer vessels, controller, insulated pipes, cable, switchboard etc.

Final 30% was labour including design, commissioning, certificates, grant application, site plumbing and electrical.

ISTR if not done by MCS then you need approval by planning or building control, can't remember which.

Having got involved in a pellet boiler using rhi and an mcs installer, i’ll be very wary of getting involved in anything similar again. I’d rather wait 10 years for the industry to mature and the cowboys to have left the range before looking to change.

We just put in air to air at the end of Feb. No grants available at that time . 4.5kw unit with two heads for £2744 installed which was straight forward. The heads were back to back on a partition wall. This was to replace a 12 year old 12kw unit with one head, multiple heads did not seem to be an option at the time. It was to cover an open plan area kitchen ,dining , family type space. The new heads focus on the dining area and a snug sitting room. The weather was still not great up here in Orkney when fitted , they are working well and about £1 a day cheaper to run when needed. The house is triple glazed and 150mm kingspan insulation.
To get on to the original post I wasn’t confident enough that an ASHP that size would cut the mustard heating radiators , I personally feel it will be difficult for it to compete with a gas or oil boiler. A larger unit is obviously an option but I don’t think it will be cheap to run. A friend of ours has ground source to radiators and has had no end of issues, mainly not being warm enough even with oversizes radiators. I think air source and ground source are well suited to underfloor applications but that won’t be an easy retro fit to replace gas or oil.
Not very scientific, just our experience of air to air over 12 years.

I am seeing similar price inflation on quotes for an A2A unit. Single unit installed on either side of a wall with a 3m pipe run and good access to electrics. Couldn't be simpler. 3.5kW kit is about £750, but installed quotes are £2500ish - not inc electrical hook-up. Going by other forums, folks were getting quotes about £1200-1400 last year.

I was speaking to an installer the other day about these grants, and apparently the rules are strict and they don't get paid promptly, and the installer takes a risk in that if for any reason the installation falls foul of the rules then they won't get paid.

I applied for a non domestic RHI last July, I am still waiting for them to approve it and start paying.

I suspect most installers would prefer it if there wan't a grant and most probably add a risk premium to their prices.

Posted By: SimonDI find it very worrying that so-called installers are making these kinds of claims/statements.

I find it more worrying that government haven't specified the rules clearly enough that installers and customers know the right answer (whatever that is) without having to think too hard.

But I can't say I'm surprised :(

https://www.gov.uk/guidance/vat-on-energy-saving-materials-and-heating-equipment-notice-7086

"Another example is the installation of an air source heat pump together with new radiators and pipework in residential accommodation.

"This is carried out as a single job and for a single price. Larger radiators and pipes are necessary because the air source heat pump operates at a lower temperature than a traditional gas boiler. The customer regards the work as one supply of an air source heat pump.

"In this example, the installation of the new radiators and pipework are ancillary to the installation of the air source heat pump.

"This single supply benefits from the zero rate in Great Britain or reduced rate in Northern Ireland"



Seems clear to me.

Don't think it needs that much thought? The example covers the most common situation.

The bit that I quoted is clear about GB versus NI (last line) (this because of NI's status re EU Single Market).

The preceding paragraphs which I didn't quote, explain the only criteria is whether the radiators are "ancillary" to the ASHP which means they are "a better means of enjoying" it.

There's no restriction on whether they are itemised, and they don't have to be necessary, or recommended, and the customer's opinion is not relevant to the VAT people. The rads just have to make the heat pump "better" to be eligible for zero VAT.

The MCS installer I was lining up, emailed me the day after this was announced to deduct 5% VAT from their previous quote. Think it would have been big news in their trade press, they understood it clearly, tho Barnacle's seem not to.



Barnacle, another consideration is decommissioning your existing boiler, removing the flue, removing the underground gas supply and meter - is probably not in the quotes. Also ask for a price for any annual servicing, this was quite expensive for our last ASHP and was a condition of the 7-year warranty.

@nigel - I was told by the installers I'd have to take on the risk of the installation not being eligible for the grant (not the installers) - so they shouldn't be adding a risk factor for that

Posted By: djh

Posted By: SimonDI find it very worrying that so-called installers are making these kinds of claims/statements.

I find it more worrying that government haven't specified the rules clearly enough that installers and customers know the right answer (whatever that is) without having to think too hard.

But I can't say I'm surprised :(

You're right, no surprises there. Obfuscation seems to be the order of the day, not just with energy policy.

Posted By: WillInAberdeenDon't think it needs that much thought? The example covers the most common situation.

I think it seems to make it deliberately unclear and complicated, this especially the case when using 'ancillary' and 'a better means of enjoying' as a measure of qaulification. In essence this means the determination of zero rating is not a technical one but value judgement.

For example, as I said above, if you're replacing an existing fossil fuel wet heating system with a heatpump, following the Domestic Heating Guide, which is arguably the industry standard, the difference in flow temperatures would require a change of both the pipework and heat emitters. This is a technical requirement for the system to function as designed and to provide the intended energy savings. This is not a 'recommended' or 'ancillary' change to the system that provides better means enjoyment of its use, it's about the fundamental physics of the system.

The consequence of this is evident in this thread.

But to take another example used in the document. When replacing a roof, insulation is neither ancillary, nor is it for better means of enjoyment, it's requirement under building regulations. The least they could do is recognise that and make the supply and install of that portion of the build zero rated. But the perversity is that using the very example of the loft hatch, in our previous renovation of a mid 1800s workers cottage, in order to upgrade our loft/roof insulation, we had to lift the roof. In this case, those works would have qualified under 'ancillary' which I bet the HMRC would want to question.

The whole policy just leaves too much open for interpretation from a technical perspective. So just like the whole grant scheme, it's yet another mess waiting to unravel.