Air source heat pumps

[bluebellbow]

We are self building our new house and as such cannot put in a gas boiler due to government rules on new builds. As I understand it our options are air source heat pump, ground source heat pump and biomass boiler. Husband wants to opt for air source heat pump. I’m just looking for an idea of running costs please? The house will have five bedrooms all ensuite. From the little I’ve read so far, we can apparently apply for a grant towards costs (which look to be £25k plus) as we are self building? Has anyone managed to go this? It sounds like it’s most efficient to do it with wet underfloor heating, does anyone have this set up? Does anyone know what equipment you have to accommodate in the house for this system, from what I read it seems like it’s the actual pump unit outside, then inside just the water cylinder needed and obviously the stuff for the underfloor heating under the floor? I will have a cupboard downstairs the size of a standard airing cupboard basically- will this be ok to house the cylinder? Thanks for any advice, we are wary of making costly mistakes as we know nothing about it! Also if anyone can recommend any companies in the south east you’ve used who install these systems… thanks

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Updated by MNHQ
Landed on this page in search of heat pump advice? Find our guide to installing a heat pump in your UK home here. HTH!

I can just tell you what we have. 2 air source heat pumps for large 5 bed and 4 bathrooms. Water cylinder is in a cupboard on the landing. We also have an immersion heater boost it when we have guests. If you are a big family, look carefully at hot water needs.

We have lowish energy costs because we have 24 solar panels and 4 batteries for storing our generated electricity. This set up is a no brainer if building from new. Ground source heat pumps are probably better if you have the space. I didn’t want my garden dug up.

We have wet underfloor and radiators. A mix. Your water temp is lower so over size radiators. Wet underfloor is fine but we did have a leak.

Our system was put in 13 years ago but solar panels and batteries added recently as electricity price hike was taking us to over £1000 a month. We were oil though. No gas. We have an electric car and have now seen a great reduction in bills. Use timers and a green tariff for the elec supply.

Definitely get solar panels and batteries though. Good insulation is a must and think about hot water needs and siting of units. They need airflow and expel cold air. Our plumber was local but talk to someone early in your planning and design phase.

If your water is downstairs you need a pump to get the water upstairs. So ask a retailer and fitter.

Have I understood this correctly? Before you installed solar panels your electricity bills were close to £12k a year?

and could you please share a ball park figure as to how much the whole solar and battery installation cost? I’d like to do all this but I’m worried about how much it will cost me to begin with.

thanks

Solar and batteries, £22,000 circa. Anyone building a new large house, must include these. Various quotes (this was mid range) but pleased with outcome.

Our LA had info and firms recommended. They varied in prices. Waiting time for everything as made in China.

Did you consider just using an electric boiler with solar panels? And if you don’t mind me asking, what sort of percentage each month on the electricity bill has the solar panels saved you? Do you notice a massive difference in the yield from summer to winter? Thanks

Just out of interest could you actually build this to passive haus standards and then just have electric heating as a backup when you need it ?

@bluebellbow Wi get some details. However the heat pumps heat the house and water. We cannot just have immersion heater for water only. Not enough supply.

Are you sure the ban on boilers is actually in effect? It seems like they may not actually be banned yet...

More here: https://www.independent.co.uk/news/uk/home-news/energy-gas-boiler-ban-bills-emissions-b2645457.html
and here: https://www.altoenergy.co.uk/blog/gas-boilers-phased-out-what-plumbers-need-to-know-before-2027

Classic government say it is happening and not actually doing it. Just like the vaccine mandate on care workers that was dropped very quietly at the last minute.

@TheNoonBell There isn’t a ban but I think all planning permissions for new homes insist on them.

@GasPanic If you have a well insulated new house, you will use less power. It’s unlikely it will be none though.

@bluebellbow Having thought a bit more, what do you mean by an electric boiler? The air source heat pumps replaced our oil fired boiler. They can replace gas boilers as well. All electric can be a variety of systems - eg all underfloor heating that’s a dry system. Immersion heater for water. We wanted to
make use of the plumbing we had, not change everything.

We had the air source heat pumps in 2011. Solar panels 18 months ago. When we found elec costs were going sky high, we had to change our strategy. So we got the panels and the batteries to store our generated power. Clearly somewhat weather dependent but it will repay the outlay fairly quickly.

We have an Ashp, electric car, solar panels (no battery yet but might get one in future), hot water tank, Wet ufh in ground floor and radiators upstairs. It takes up quite a lot of space, lots of piping and the hot water tank is large. We also have a MHVR system to manage the air quality and humidity as we don't have air vents in the windows. All this was possible as we did a renovation that went back to brick. It's a lovely stable warm temperature with the ufh working at a low temperature. Sunny chilly winter days, our solar panels cover heating and hot water - a dream! But overcast chilly days it can be pretty expensive. You need to learn to use these systems to get the most of it, and make the most out of cheap electricity overnight, etc.

I moved into my self build and have an air source heat pump. My bills have been over £900/month. 4500sq ft house. It’s taken quite some tweaking to get it working and I wouldn’t really recommend it. My builder friend has ground source and his has been better I think. I would also recommend getting your towel rads done on an electric switch as mine aren’t hot as the UFH temperature is quite low and the rads don’t get hot. My heat pump and cylinder is outside in a plant room (well the heat pump is on the wall outside). It was pretty useless in the recent cold temperatures.

The best thing you can do is add extra insulation to your build. We have walls with double the insulation required for building regs. We have an ASHP too, and it costs almost nothing to run, because we never need it on. We've only had it on about 5 times all winter. Extra insulation cost almost nothing in the cost of a build, but the saving last forever.

We have solar too, but it's a red herring for heating, In winter when you need heating, there's next to no sun. There is nothing about having batteries that makes financial sense..

A self build shouldn't cost anywhere near that @Runninghappy, you need to query your architect and builder as something has gone very wrong indeed. Your radiators need to be much larger for the ashp as the water temperatures are lower.

I don’t know what you mean. I have UFH upstairs and downstairs?

@Runninghappy You said you had rads.

Our house is probably around the size of yours and we have 2 heat pumps. If you don’t store electricity in batteries from solar panel generation, it does cost what you say for a larger house using a heat pump, I said earlier our bills were moving up to .£1000 a month. Heat pumps in large houses are not a cheap as chips solution. You need the solar panels (we have 24) and store any excess they generate in batteries. That’s weather dependent. So you get good generation and then not much. This winter has been poor!

I said towel rads.

You need more than one heat pump for that size of house maybe?

That's kind of what I meant by passive haus.

If you insulate really well you will barely need any heat. You can then use standard electric heaters rather than an ASHP because you need so little electric it doesn't matter that it is costly anymore.

Spending ££££ on an ASHP when you only use it a few times a year seems pointless as it will take you ages to recover the install cost, even if the ASHP is 1/5 the price of the standard electric.

I guess two problems with this. One is when you sell you would probably have to convince the buyers the standard electric bills were really low, as a lot of people have a bee in their bonnet about the cost of electric heating. The other is how you control the humidity in a house that is so strongly insulated.

It’s a real headache, I feel like we’re going to shell out thousands and thousands to be green and be stuck with crap heating and sky high bills. I’m looking into biomass boiler now. Or maybe the option of keeping the ground slab and the front wall of the existing bungalow so we can be a “rebuild” and avoid all these restrictions. A new build is also constrained by how much water it can use too, it is honestly a nightmare.

I would insulate as much as you can and aim for PassivHaus standard or better, and have a heat exchange unit to recover heat and circulate the air, combined with solar and batteries.

Can you actually get round the building regs by building it with a biomass boiler, but then a year after it is built and has all the approvals ripping that out for a gas boiler instead ?

I presume the heating system for the biomass is exactly the same in terms of radiators/pipes. I presume there is nothing stopping you connecting to mains gas for the cooker, gas fire etc, so all the pipework can be specced to be in place ?

Thanks for the ideas, good for thought. I really do feel tempted to do something like this 😂

*food for thought

@bluebellbow Why do you think it’s a crap heating system with ASHP’s? We have a warm house. We are not passiv haus stsndards because we have some glass walls but we are insulated as much as we can be. I would have thought, building from new, you really should seek to be green. Why would you not build to the highest green standards?

It’s utterly ridiculous to say batteries are a waste of money. They store the electricity you generate. We cannot start again and rebuild! So we have the best we can get in terms of tariffs and insulation and keep bills as low as we can by storing our own electricity. Many people will suggest this is sensible. Very much so if you stay in a house for a long time. Plus depends on size of house. A small one probably won’t justify a large outlay, a large one worth several £million is different.