[Closed] Ground source heat pumps, any real world experience ?

Interested to see the responses myself, i live in rural Norfolk and we have an ancient oil fired boiler and huge oil tank in the back garden, so thought about this an alternative.

No personal experience but a friend recently moved (a year ago) into a brand new 'executive' home with that set up and he said over Christmas that he is still struggling with the set up of it, can't get the temperature right and his fuel bills are significantly higher than in his old (albeit slightly smaller) home. He said he is paying around £250 a month for a larger (I'd say around 2,500 sq ft) 4 bed detached house - I think that is ridiculously high as I assume modern standards for insulation etc along with low power lighting throughout should make it very cheap to run.

I feel your pain re the electric heating - we have a house that has no main gas and is heated purely on electric - thankfully it's a summer place really so the heating doesn't get used that much.

To make GS work you really need a wet underfloor system which would mean digging up your existing floors and starting again .... ££££.
You can get special radiators which run on the lower water temperature though.

AFAIA it's pretty good in terms of running costs but, as you've pointed out, if you get a leak then potentially you'll need to dig up the garden/floor to fix.

I have a mate who's uber-loaded and has to run his incredibly massive house on oil (£12k/year) as it's the best solution for him. He has a [sideline] property business and says that communal biomass was the only biomass that worked until last year when the RHI changed - now it doesn't make financial sense due to the high cost of the boilers/storage and increasing price of pellets.

I hate to say it but I think that oil may still be your best bet although air-air heat pumps are getting better all the time if you can live with the 'look'.

Depending upon the size of your house, number of occupants and the environment (ie rural or not) then the STW go-to of a stove also works out OK.

I should add that we live in an ex-farmhouse with an ancient oil boiler and plenty of land for GSHP - I'd love to reduce our heating costs but I'm still not sure it makes financial sense!!

Keep improving that insulation.

I discussed this with the Company that installed my solar panels.

We have no mains gas and heat with stove and oil CH.

I have a large, 12 KW solar system and they reckoned that it would make sense for me. The pumps run on electricity and they claimed a 4:1 "production".

I also have 2 large areas of underfloor heating, which work well as the system runs at a lower temperature than a normal wet CH system, so you bigger radiators to produce sufficient heat.

However, the cost was the biggest issue, somewhere between £30k and £40k. This was a vertical installation, where they basically use a drilling rig to bore a hole into the ground.

I might look at it in the future when the cost comes down but at the moment the numbers don't add up.

Would have thought GSHP would be more disruptive than other installs.
As a general rule heat pumps are best suited to well insulated houses with underfloor heating or low temperature heat emitters. Get independent advice from a specialist rather than from an installer tied to a specific technology. Can recommend a guy if you are based on the south east.

In Scotland the govt pays for an advice line called Home Energy Scotland, dunno about any English equivalent.

I'd expect you'd want a well insulated house for it to work as it isn't as powerful as a boiler.

Are oil systems really that expensive? I know that GSHP is.

Note GSHP can use radiators, but they are big. The pump won't be underground and I'd expect they use durable piping, given the expense of digging and installation.

I have some info at it at work, nudge me next week if you'd like me to look at it. May not be more than the above tho.

@ gobuchul

I have a standard 4Kw solar installation and a lot of spare barn roofspace - how much production are you averaging at this time of year?

[tempted to add a load more panels as we have an unused 3 phase power supply that I could hook into in order to get permission]

Oil and gshp are not really on the same magnitude of cost.

You might get an air source heat pump in the ballpark of an oil install but they are mostly horrific to run.

I know one guy who raves about his an tries to push it on every one but he's an eco warrior and I suspect he wouldn't tell us the true cost even if it was bankrupting him.

I know a few others who say they are being bankrupted by their air source heat pump here in Scotland.

how much production are you averaging at this time of year?

I don't keep a close eye on it TBH. the wife does the reads. However, a lot less than in the summer as I am quite far North. We have a device that diverts any surplus to our immersion heater, so we don't use any oil or electricity to heat our water for about 9 mths a year. In the winter I have to switch the HW on most days.

Our electricity bills have reduced dramatically since the installation.

Once the technology improves I will be installing a battery. Also considering an electric car when we need to replace current one.

I know a few others who say they are being bankrupted by their air source heat pump here in Scotland.

Air source heat pumps can be very expensive to run, if setup and used incorrectly. ie without a buffer tank. So it is cycling on and off all of the time. It seems this is quite common in some modern houses, people think the tank takes up too much space.

A good air source heat pump can give a coefficient of performance of 2 or 3 most of the time.

We have got maybe ten or twelve of our services with air source heat pumps - we reckon they are costing us around four times as much as we'd expect from a similar gas fired service.

Old boss had Air source pump - the running costs were horrendous through a Scottish winter, on the north slope of a hill. Buffer storage or not, you try getting energy from air at -3... They now switch off the ASHP under freezing and crank up old oil filled radiators and claim it is cheaper.

Their holiday home had GSHP - it had some issues when first installed through leaks in the borehole etc. Once set up, it was reasonable cost to run, but this was in a super insulated (AECB Gold) house with underfloor heating. His comment was it will never ever repay the install costs, and wished again he had gone to tanked oil or gas, or just installed more woodburners.

How well insulated and air tight is the house you have?

Can you use solar panels, electrical storage and existing electrical heaters?

wouldn't that be cheaper?

Can you use solar panels

The problem with solar panels for heating in the UK, is that there is a lot less sunlight in the winter and the panels produce very little power when you need it. Also, with a single phase supply you are limited to 3.7kw, which isn't a lot.

I think @Alex had something like this installed when he moved into his house - is that right?

The problem with all Heat Pumps is that electricity is relatively expensive in the UK, partly due to the industry having to absorb the cost of the various green energy incentives, which means it difficult to get the numbers of work when comparing to other heat sources. If there is a cooling requirement, then they have a fighting chance.

You need to size any heating system for the heat demand of the house, and you need to match it to water temperature for rads vs underfloor. This doesn't necessarily mean GSHP needs a well insulated house, but it does mean you'd have a larger heat pump and a longer run of collectors for a less well insulated house. They are more often fitted to new builds because retrofitting UFH is clearly going to be expensive and disruptive and they don't work well with rads.

I do know of one in an old place that uses rads though. It's in a vast leaky old mansion and its owner is happy with it by running his rads on lower than normal rad temperatures pretty much 24/7. I think he replaced some but not all rads. I don't know the financials but he's unlikely to have done it if they were bad. By running it 24/7 he is using it in a different way to how people are used to running heating systems historically and I suspect one of the reasons for poor performance in some of these systems is that folk sometimes can't get their heads around that kind of change.

Comparing ground source with air source on pure financial terms I reckon for my own installation (GSHP, new so no real operating experience of this one yet) the RHI payments I receive, plus a slightly better coefficient of performance, will make up the extra install cost, and in use I hope it will be better because the points above about the effectiveness of ASHPs in low temperatures seem to be commonly accepted. I understand manufacturers are saying this has improved with newer models but it stands to reason that they'll always find it a lot harder to extract much heat out of very cold air than warmer air, and the colder it is out the more you need.

In looking at the numbers one thing I would observe is that people tend to look at historic/present costs rather than taking a prudent view on the future and I think one should expect big change. Where will oil costs go over the (say) 20 year life of the system you put in? It wouldn't surprise me if they don't take long to double and more. How will your own views of the importance of your carbon emissions change over time? It wouldn't surprise me if they change somewhat too.

Having said all that I also need to replace an oil boiler in another house. I might chicken out of greener options and go with oil but if I do it'll be a shame.

The point about electricity costs can in some cases be well mitigated with PV, which I intend to do on my new build (and maybe a battery although I probably won't do that for now). Today's PV install costs do look quite good against the cost of electricity.

We have both ground source and air source heating. GS installed in 2007 and AS in 2014 (when house was extended). We live in rural Aberdeenshire on a fairly exposed site.

First  I would reiterate many of the comments above - you need to use with an underfloor system because it operates at a lower temperature than other forms of heating, typically 45-50 degrees. Also the house should be fully insulated to current standards. Ours made sense as we did a complete renovation of an old croft cottage, stripping out the interior completely, and we have no gas supply so the alternative was LPG or oil.

The GS has a borehole to 110m depth which is generally OK but there have been occasions when we may have had problems with the flow but can't confirm. There are one or two things I would change if I could but it's a bit late now. When we had it installed we got a grant towards it - don't know what's available now - but it cost around £13k less £4k grant. There were also issues with the supplier/installer regime at the time which have, I believe, been sorted out which would probably make installation more straightforward.

The AS was installed when we converted (actually demolished and rebuilt) an adjacent byre. We couldn't extend the GS so had to have a separate system.

It took some getting used to in terms of running the system. We were on Economy 10 electricity because it is a renewable resource, so I tried to run it around the 3 cheap rate periods. It proved difficult to control, particularly domestic water heating. Then I was advised, by the people who installed some PV panels later, that it is better to run the heat pump continuously and control the on/off cycles with individual room thermostats - this helps to maintain the temperature of the concrete floors rather than repeated heating and cooling. This certainly works better than the other way and the house is usually very warm and hot water available.

Cost-wise it is difficult to say. At the time we moved in we left a small semidetached cottage with 1 and1/2 bedrooms heated with oil to a 3 bed cottage. All our energy costs are the electric, so comparing to oil plus electric before, it wasn't dissimilar for a larger house. 11 years on I don't have anything as a comparison. Our electric bill is about £230/mth but we are currently about £900 in credit.

Hope that's some help. If you have any specific questions feel free to ask and I can try to answer.

We have an air source heat pump in our house - but ours in a new build (bought last year) and is very well insulated - part of an eco build by an independent builder. As a system it's great. It takes a little longer to warm the house than a regular system, but once it's up to temperature I don't notice any difference.

Our whole house is electric only, and our bills are relatively small - I think we pay less than £100pm for everything. But then the house is so well insulated we don't have the heating on very often.

The pump lives out in the garden (it's quite big) and other than that I don't notice any difference from a regular system.

We have a Ground Source system also installed in 2007. We chose to do it as

- there is no gas main here and we’d had oil before and we want it again (£ mainly)
- We have a big garden that was basically a car park (old B&B) so we didn’t have a issue digging it up like a WW1 trench system 🙂
- The house only had storage heaters when we moved in. Rubbish. House not terribly well insulated either. Our first quarter electricity bill convinced us to get a move on.

We use NuHeat, they designed it, we installed most of the pipes through the house. This wasn’t an issue as we had the floors up. We did need to raise a couple of lintels as the system we used with the insulation and engineered floor on top was about 5 inches deep.

We opted for big rads upstairs as we’d run out of money/enthusiasm to rip up everything up there. The actual heat pump is not huge (‘Fighter’ - swedish design and manuf) but the cylinder is a whopper! Barely got it into the house. Plumbing was a bit complicated but specialists got it going.

In ten years we’ve had only one issue with a solenoid going pop. It’s serviced every year. We don’t have thermostats, we use the flow valves on the manifold (we have 2) which is a bit crude but it mostly works. We never turn the pump off, it goes into ’summer’ mode so only heats hot water between abut May and September.

What’s good
- lovely heat across the whole floor (downstairs) with no hot or cold spots
- cheap (ish) compared to any other solution
- makes rooms very tidy as no rads (downstairs)
- Plentiful supply of hot water - its not as warm as you’d get in a boiler system but it’s hot enough
- Rads upstairs (including some cunning bathroom ones) are fine.

What’s not so good
- takes a while to adjust if it gets very cold
- if it goes wrong, it’s not easy to diagnose what’s happening
- we live in fear of a pipe bursting 3.2m below ground (and now below the garden) in one of the trenches

We basically had a perfect set of circumstances. If I was doing it again and didn’t have access to a borehole or a big garden to run 300m+ of pipes, I’m not sure we’d do it. We did mean to augment it with solar (as we have roof space and the system is configured to use it) but we never got round to it.

Grant for us was about £5k I think. System about £14k. Installation can’t remember. We did also look at air source but at the time GS was a better option if you could get the install done cheaply.

Hope that’s helpful.

I don’t seem to have many photos but this was early in the process

[url= https://farm4.staticflickr.com/3359/3476699311_49f508fed8_b.jp g" target="_blank">https://farm4.staticflickr.com/3359/3476699311_49f508fed8_b.jp g"/> [/img][/url][url= https://flic.kr/p/6idZzz ]The Manhatten Experiment[/url] by [url= https://www.flickr.com/photos/alexleigh/ ]Alex Leigh[/url], on Flickr

Labrador added for scale 🙂

[url= https://farm4.staticflickr.com/3369/3476707059_77757317f7_b.jp g" target="_blank">https://farm4.staticflickr.com/3369/3476707059_77757317f7_b.jp g"/> [/img][/url][url= https://flic.kr/p/6ie2Ta ]Murphy - 11 months[/url] by [url= https://www.flickr.com/photos/alexleigh/ ]Alex Leigh[/url], on Flickr

Thanks for all the information. Alex, what are your monthly/yearly running costs, either KWH used or monthly electricity DD in £?

Mike, thanks for the offer, I may well be in touch.

I don't think there are any grants these days, just interest free loans.

Our whole house is electric only, and our bills are relatively small – I think we pay less than £100pm for everything.

We pay £60/month for Gas + Elect and live in a solid walled Victorian House with no insulation and wind coming up through the gaps in the floor boards! I would expect a well insulated modern home to be around £20/month in bills!

RHI tariffs are how financial support now works, so yes you have to find the money up front but much of it will come back to you over time. I'd start by multiplying a rule of thumb kwh per year for a poorly insulated old house by today's RHI rate to estimate how much support you could expect. For GSHPs you now get a higher going rate for a shorter 7 years.

Stating the obvious perhaps but I wouldn't be surprised if various other measures to reduce your energy use stacked up well enough financially to be the first things you might do, especially if you find you have a couple of really bad offenders. My previous house had bare timber floors throughout the ground floor with a void beneath - pretty easy and highly effective to insulate under - plus inadequate insulation in the loft. Fairly obvious things that transformed the place. If any such opportunities arise then your new heating installation, whatever that may be, should decrease in output and cost.

I would expect a well insulated modern home to be around £20/month in bills!

I think that's a little optimistic! It's a four bedroom house, with a family of four living in it using electric for heating, cooking, lighting etc. £240 per annum in bills would be ridiculously low.

Not sure of the costs. I’ll ask the better half and let you know!

"We pay £60/month for Gas + Elect and live in a solid walled Victorian House with no insulation and wind coming up through the gaps in the floor boards! I would expect a well insulated modern home to be around £20/month in bills! "

you missed the caveat that your in a city in the south of of the country.

YMMV with someone who lives on top of a hill in the north of scotland.

regardless of insulation - the temperature differential would be greater for one thing.

Alex, good to see your comments on GSHP and Nuheat as they are one of the companies I was looking at for ours having met them over in Swindon.

We are planning a single storey barn conversion so have the chance to put in any floor we want and will be going with pretty much the whole south side glazed (triple).

I've ditched the wood burner from the lounge in favour for an electric powered Aga and 50 or so PV panels on the lambing shed roof along with battery storage etc.

I am just hoping we get the damn planning through before any RHI payments are axed.

We have 3 acres of land, all in a sunny south facing location at the foot of some hills so pretty much sunshine all the time, we also have a river about 200m at the end of the field we could have used if it was closer.

We had good experiences with NuHeat. Not a big firm so sometimes takes a while for them to get back to you, but really know their stuff, very friendly and helpful. We’d use them again.

Single story, new floors sounds perfect. And those barns are sometimes difficult for rads etc. I reckon that’ll be lovely with ground source. Sounds like you could do Solar as well.

Following this with interest. starting a new build in a few weeks with Air Source heat pump, under floor heating and house well insulated. Log burner in living area. I am concerned about some negative things im seeing on various forums about poor performance.

Off on a tangent but isnt PV with a large hot water tank suppoesed to be the most viable system?
PV panels genertae 'in feed' monies, but electronics move the electrcicity to the element in the header tank- you get paid to heat up water.
Then you pump this around the house , limits are roof area and KW as there are limits to what you can push through 240V systems without specialist wiring
This was relayed to me by a greennie , although the basis of it sounds logical.
You will still have to have electric heating though , PV cannot generate enough to heat a house 12hrs a day , every day , for 5 monnths

electric powered Aga

Don't do it. Look good and cook well but cost an absolute fortune to run.

There was one fitted when we moved into our current house. Keeps the house warm in the winter but then it's mainly running of mains rather than the PV and uncomfortably warm in the summer when it's running off PV, when it's better to have the PV heating your water.

Sold ours and made huge difference to our electricity bill.

Andyl I’d consider going down the passivhaus route instead of a GSHP.
The money spent on extra insulation could be well worth it as it would outlast any RHI payments and virtually zero maintenance cost.
You would probably need some heating but you could achieve that with a well place wood burner. And you would also need some MVHR so there is some maintenance needed on that system.

@ brickwizard: Have you taken a look at the Navitron forums..... loads of info there. From what I've gathered though, air to air works OK but air to water is a a much greyer area and may not be that brilliant.

@ Andyl: 18 months ago I looked to putting an electric Aga in as part of a kitchen refurb but from an economics POV I can't see it working.
The old Agas that have been converted to electric are very inefficient (which is what makes them good at heating the kitchen) so you may as well spend less money heating using a better fuel.
The new electric Agas are more efficient (because they put more insulation in) but now they don't heat the kitchen as well! They do have the 'intelligent' ones that you slumber most of the time and then turn up when you want to cook on them (my sister has one) - but then you may as well have a normal oven that's more efficient and better for cooking on
This is ignoring the £10k initial purchase cost!!

Don't think the PV will run the Aga during the winter - our little 4Kw system produces about 1Kw/day in Dec/Jan so you'd be looking at about 2.5Kw/day....... that's not very much!!
[I've got a number of years of detailed production history on the PV Output web site if you want to take a look]

Of course if you're loaded then fill your boots 😉

Wood burning stove def FTW in many cases.