Solar, Heat pumps and grants

Akerfraken

I have a large old bungalow which at the moment has a gas combi boiler for heating and hot water.  After a few years I found a Solar contractor who understood my desire to use solar for for heating and hot water and get rid of gas completely. As we have a pitch roof on for sides with one South facing a big enough solar system with battery back up is not a problem. Due to the age of the bungalow ASHP or GSHP have never been a sensible option. So we intend to have a Solar Assisred Heat Pump for hot water ( with cylinder in loft ) and an electric boiler for the heating.

Now the question,If I fitted solar system alone there are no grants available, if I change the gas boiler for electric boiler the same no grant but I feel that if I fit the system I intend to in essence it is the same as fitting solar and ASHP which would attract a £7.5K grant.

Any comments or advice where I can confirm the theory would be very welcome.

thevilla

Please explain why the age of your bungalow rules out a (300 - 400% efficient) heat pump in favour of an electric (100% efficient) boiler?

Solar is great but not for 3 months in winter.  I'd suggest you need another design iteration.

Martyn1981

Myself and others have gone down the route of installing an air to air heat pump (or two). This is a modern air conditioning unit, that can heat as well as cool. They cost ~£1,500 to have installed.

We have a two storey house (actually three with loft stairs), and the downstairs A2A units supply most of the upstairs heat too, so they are ideal for a bungalow.

Might be worth you thinking about. But you will also need to think of water heating, perhaps in-line heaters, or a hot water tank.

With PV to help a bit in winter, and batteries to store cheap rate leccy charged at night, you should be able to heat the house cheap, and from Mch to October, the PV should provide most of the leccy needed.

Our leccy and gas* bill for Jan, which was the highest of the year, was ~£100, and that includes 'fueling' the two EV's. April should be about £30, mostly standing charges and about £6 for gas.

*We still have a gas combi for hot water, and gas oven, but they will probably go this year.

QrizB

Akerfraken said:

If I fitted solar system alone there are no grants available, if I change the gas boiler for electric boiler the same no grant but I feel that if I fit the system I intend to in essence it is the same as fitting solar and ASHP which would attract a £7.5K grant.
Any comments or advice where I can confirm the theory would be very welcome.

The Boiler Upgrade Scheme has quite specific rules and takes no account of anyone's feelings.

https://www.gov.uk/apply-boiler-upgrade-scheme

Akerfraken said:

... an electric boiler for the heating

You are going to triple your heating costs for no appreciable benefit.

skkhansk1998

Your question about whether combining solar with a heat pump qualifies for a grant under the Boiler Upgrade Scheme is a good one — and you're not alone in wondering this.

Based on my own research, the Boiler Upgrade Scheme (BUS) offers grants specifically for the installation of air source heat pumps (ASHPs), ground source heat pumps (GSHPs), and biomass boilers in certain off-gas grid areas. Unfortunately, electric boilers don’t qualify, even if paired with solar, because they’re not considered renewable or low-carbon under the scheme's criteria.

If you're planning to install a solar-assisted heat pump, the key is whether that heat pump itself meets the BUS eligibility requirements — i.e., it's properly sized, meets efficiency standards, and replaces a fossil fuel system. If your system is viewed as a compliant heat pump installation, you could still be eligible for the £7,500 grant. But if it’s considered more of a hybrid or supplementary system (like with electric boilers), then unfortunately, it might not qualify.

I was in a similar situation recently — trying to understand what systems would actually make me eligible. I ended up applying for support through marigoldeco.co.uk. Their team helped me understand what kind of upgrades might be covered under the ECO4 scheme and what wouldn’t. They’ve already done a basic review of my property, and I’m currently waiting on the full assessment and hopefully some confirmation soon.

So far, the process has been pretty straightforward, and I’ll definitely share how it goes once I hear back.

Martyn1981

Akerfraken said:

So we intend to have a Solar Assisred Heat Pump for hot water ( with cylinder in loft ) and an electric boiler for the heating.

Just a thought, but are you referring to a heat pump hot water tank (HPHW) for the water?

I'm getting a HW tank this, and came very close to getting a HP model, but I'm a bit concerned about the noise, as it will be against a party wall (semi-detached house). It might drive someone on the other side mad. But I'm also considering the loft.

The only downside for me is the noise, as I'm happy to spend the extra money, despite it probably never paying the difference for us, v's a cheap rate leccy heated normal HW tank.

This is one of the models I was looking at, which also has a heat exchanger, so could be used to heat a small CH circuit or underfloor heating*. But of course that would drain the heat faster, so daytime power might be needed in the winter, but that's when the batts charged on cheap rate help.

*My idea was to run the upstairs CH circuit off it (just 4 small single panel rads), to avoid heat top up with oil rads, but after experimentation, a simpler solution was just to turn the two downstairs A2A units up one degree.

If your property isn't too big, then one of these in the loft, topping up rads, with an A2A unit providing most of the heat, might work well for you.

You might also want to wait and see what the Gov decides in the review of the warm homes scheme. They have suggested support for A2A units, but no idea what that means. It could be widening the HP subsidy support, or just reducing VAT ...... your guess is as good as mine.

Martyn1981

Regarding support for A2A units, and other possible changes, here's what the Gov media mentioned last year. But we will have to wait and see what is done (or isn't) to change/update things.

Warm Homes Plan and heat pumps

The changes, which are being made by MHCLG early next year, will amend the existing permitted development right to:

• Remove the 1m boundary rule, enabling heat pumps to be installed within 1m of the property boundary.

• Increase the size limit of the heat pump for dwellinghouses from 0.6m3 to 1.5m3.

• Double the number of heat pumps permitted, from one to two for detached dwelling houses.

• Support the rollout of air-to-air heat pumps that can also provide a cooling function.

Akerfraken

thevilla said:

Please explain why the age of your bungalow rules out a (300 - 400% efficient) heat pump in favour of an electric (100% efficient) boiler?

Solar is great but not for 3 months in winter.  I'd suggest you need another design iteration.

The bungalow is over 100 years old with solid walls which would be difficult and expensive to insulate also various floors some solid some wood. Fitting an ASHP would involve all new (bigger) radiators a least and would not be cost effective.

The starting premise for the system was that we should get rid of the gas and wood burner we use quite a bit in winter and most important net zero cost over 12 months. The system we are having does this.

My big query was if I did install a ASHP I could get £7.5 grant  ( not boiler replacement grant ) whereas we are fitting SAHP for hot water and electric boiler for CH achieving the same outcome just a different heat pump.

QrizB

Akerfraken said:

My big query was if I did install a ASHP I could get £7.5 grant  ( not boiler replacement grant ) whereas we are fitting SAHP for hot water and electric boiler for CH achieving the same outcome just a different heat pump.

If the £7.5k grant isn't from the Boiler Upgrade Scheme, what scheme is it under? Until you share the name of the scheme, no-one will be able to answer your question.

Akerfraken

QrizB said:

If the £7.5k grant isn't from the Boiler Upgrade Scheme, what scheme is it under? Until you share the name of the scheme, no-one will be able to answer your question.

Sorry it on further reading it does appear to come under the Boiler Upgrade Scheme which if I am reading it right does allow for hybrid systems but I’m not at all sure as there is some mention of electric boilers being fossil fuel boilers.

Martyn1981

I appreciate your frustration that going to an electric bolier isn't supported, but in fairness it's not the same result as an ASHP. The leccy boiler will be ~100% efficient, but an ASHP will have a SCOP (seasonal co-efficient of performance) of ~3, thus using about 1/3rd of the electricity of the leccy boiler.

Only my opinion, not trying to guess at Gov thinking, but it's the move away from FF heating, and the reduction in demand for leccy, which I think they are aiming for, especially given the huge increase in winter demand for leccy that HP heating will bring.

You may find that a high temperature ASHP will serve you well, this can run at 'normal' ASHP temps when heating demand is low, but also at higher temps (with a reduction in COP performance) when needed. HT ASHP's shouldn't require any significant change to the pipes/rads in the property. They are now available.

I too hit a wall when looking into getting an ASHP. Despite an annual gas consumption of ~6,000kWh (including DHW and oven), and an EPC of high B, our quotes were around £13k-£14k, with about £6.5k for us to pay. This was a reflection of the house age, and EPC description of property. So I get your frustration.

Our solution was actually the PV batts, allowing us to run the two A2A units 24/7 in the winter, on cheap leccy*. That's why (given your mention of PV and batts) I keep mentioning A2A units for you, as a simpler and cheaper solution, certainly when it comes to annual bills. [Edit - you could also keep the wood burner for emergencies.]

*Even without the batteries, we experimented in early 2024, by running one of the A2A units hard through the 6hr cheap rate period, to help warm the house, and reduce GCH use. This worked very well, and actually provided almost all home heating by Mch 2024, as temps rose.