Anyone got one? One of the other forums I read many seem to have at least a year of running now so have a pretty good idea of wat they cost.
Though very few are giving a real insight. It feels to me they might be hiding behind "I'm doing it for the greater good" kind of comment which makes me think they may be quite costly to run.
OTOH people are saying about having the whole house at a fairly constant 20 degrees or whatever, which has some attraction.
I have a call with Octopus on Tuesday to explore costs. Base price seems to be a bit over £3k but I think I would have to have additional loft insulation, possibly also losing it as a storage area as a result, and also the water tank may need to go up there as the airing cupboard isn't big enough, so probably quite a lump of cost on top.
Any real experiences here of the practicalities and cost that people would like to share?
Last edited by: smokie on Tue 4 Nov 25 at 23:52
|
£3k is a fraction of what it will cost to do the whole house.
I currently have fairly ancient GCH. Since moving here a couple of years ago we have done a full renovation with new kitchen, bathroom, utility room, flooring, walls down etc etc.
At some time I will have to replace the whole system - boiler, radiators, pipework etc. Rather than wait until it goes and replace like for like, I want a plan as replacement like for like will disrupt flooring and decoration throughout adding significant cost to the bill.
Conclusion - fitting a system to heat and cool the house (as often installed in southern Europe) will create minimal disruption + extra space internally with removal of radiators.
For a 4 bed house I estimate:
- the units for heating and cooling alone ~£5k
- possibly another £2k for water heating - air source alone is fairly marginal for hot water
- fitting - probably a week or so for the whole system
- a couple of days for radiator removel +make good
If you are intending to use the existing radiators rather than wall mounted air con units you may need to increase their size as water temperature from an ASHP is lower than GCH boiler.
Overall I estimate the cost for a fairly modern 4 bed 2 bath house at ~£12k.
|
My two-bedroom, seven-radiator terraced house is not suitable for a heat pump (ground or air-source), and as my current Worcester Bosch combi boiler is still being reliable and parts are still available (not that it has needed any during its 15 year life, just annual servicing), I will keep it until 2030-2035, when I will upgrade to another combi-boiler.
That was a recommendation given to my by the last two gas engineers who have serviced my boiler. The cost of a new combi-boiler and installation will be less than £3,000.
|
|
My 1930s bungalow would laugh off any attempts by a heat pump to try and heat it.
Last edited by: Zero on Wed 5 Nov 25 at 09:08
|
A son lives in Texas. He has a house with AirCon for 9 months of the year and, flick a switch, for 3 months or so it acts as the heating system.
He bought his highly insulated house from a builder and for the first 2.5 years, all was well,
In Feb 2021 there was a serious cold spell - instead of typical winter lows of say 10 -15C it became -10C.
The AC/ASHP heating was non-existent- the house was an icebox for roughly 5 days.
|
>> My 1930s bungalow would laugh off any attempts by a heat pump to try and
>> heat it.
I think it would work in principle for my late nineties bog standard estate 4 bed but I understand heat pumps are not compatible with the narrow bore pipework installed at build.
Replacing that would be a mammoth task
Current 1998 Baxi boiler works fine and passes Annual Service with no more than a clean of the exchanger.
If it goes bang I'll replace it with a modern condensing equivalent.
|
I thoroughly investigated going down the heat pump route a few years ago, when I guessed - correctly - that the boiler would need replacing.
We are in a detached house with insulated walls, modern double-glazing and good loft insulation that could perhaps be improved a bit.
My conclusion was that it would be relatively expensive and might well not provide enough heat without expensive modifications, especially in cold snaps. Also, due to the narrow plot the house stands on, positioning the pump would have to be on the back or front - both highly unsightly.
|
We got ours and solar panels for nothing in July last year under some scheme the Welsh assembly worked out with the energy companies. I reckon we save around £500 pa compared to gas, without the solar panels we would be marginally ahead at best. It heats the house as well as the old gas boiler and the water is just as hot.
Paying for it all ourselves would have made it a no-no.
Last edited by: Robin O'Reliant on Wed 5 Nov 25 at 11:48
|
This 3 bed detached owse was built 7 years ago. In the 11 months we've been here, the Samsung has cost us 900 notes in repairs & servicing.
A lot of 'pumps are thrown in new builds by sub contractors under ECO4 scheme and there are many stories out there of peops having all sorts of problems with setting them up properly - which the installers should have carried out ... if they knew how.
Heat pumps work fine if a heat loss survey is carried out and the correct size 'pump is installed by engineers who aren't just fit and move on merchants.
Check out the Facebook groups:
Heat pumps UK
Heat Geek's Heating Help for Homeowners
Heat Pumps UK and Ireland
Samsung Air source heat pumps
|
Well there you go. Most opinions sort of match my instinct from c 12 months ago.
The Octopus £3 and a bit k assumes a sizeable govt grant - £7.5k IIRC - and certainly a while ago their price included any other additional work required eg new rads etc. Not sure about small bore also I think installation of the water tank in the loft is an extra (also additional lagging).
But other than conjecture about what may or may not be a sticking point does anyone have any data about what they actually cost to run, to provide an equivalent amount of heat and hot water?
|
Running costs should be fairly close to conventional gas heating.
Current price cap per kwh for electricity is 26.35p and for gas 6.29p - electricity cost is ~ 4 times that of gas.
A ground source heat pump has a coefficient of performance of 3.5-4.5. Air source slightly less and more variable due to weather and climate - ground temperatures tend to be stable. Broadly there may be minimal differences in running costs.
Other factors make precise comparison difficult and may dominate the decision:
- incidental costs of installation - larger radiators, new pipework, disruption to decor
- space onstraints - how easily a heat pump can be sited
- local climate - ASHP are more sensitive to low ambient temperatures
- benefits of modern control systems when replacing one with limited control
- total cost of the project
Replacing an existing gas bolier happens every 15-25 years. At some point gas boilers will be banned. Over time gas distribution networks will become increasingly expensive to maintain and probably more costly as the number of users fall.
Last edited by: Terry on Thu 6 Nov 25 at 12:11
|
I have one. Cheaper than oil in the shoulder months, probably more expensive in the really cold season. No real noise issues. More comfortable than oil/gas because the house is just a consistent 21C.
Have experienced one problem with mine that I think is a thermocouple on the heat exchanger and the engineer thinks is a far more expensive part. I can't admit to him that I had the cover off and put a meter across the thermocouple to validate the fault, so we get to watch him replace parts at random until he gets it right. At least I put all the screws back in when I took it apart. (This is a Daikin engineer, the Octopus installers were great).
No noise problems. If you turn it off (eg holiday) it does take three business days to warm the house up again so I just leave it on all the time.
|
Thanks FF.
"More comfortable than oil/gas because the house is just a consistent 21C."
For me this is the selling point. We swing from too hot to damned cold and no amount of tweaking settings and TRVs has ever really allowed us to get the house near an even temperature - although I dislike heated bedrooms and heated unused areas so maybe there is no solution to it.
However I'm thinking as I enter my twilight decade sod the cost (within reason!), let's just go for comfort.
OTOH we do have a fairly new boiler which allegedly is fairly efficient and it seems a waste to dispose of that!
I have Octopus calling me on Tuesday to discuss and maybe the deciding factor will be what additional spend there would be to bring the house up to spec to be eligible for the grant.
|
We have a ASHP, 3 years now in our 'self-build'.
I wouldn't think it has saved us any money, simply because Electricity costs 4 x as much per kWh as gas.
Our total energy usage is 8800kWh per year of which about half is the heating, maybe 4500kWh.
Our worst year in our old bungalow, which had half the floor area of the new house was 27,000kWh of gas which we used only for heating! But it was poorly insulated and somewhat draughty.
We run the heating and hot water 24/7. Two reasons, the heat lag is significant and also the system is sized relative to the calculated heat loss so it does not have the grunt to add a lot of heat quickly anyway. It's an 11kW** output and the heat loss IIRC is about 6.5kW in cold conditions.
It's not desirable for the ASHP to be too oversized because it's less efficient when it runs infrequently. This can also be managed by using the minimum required flow temperature. We have underfloor heating throughout and in the Spring and autumn the flow temperature is probably only 34-36 C.
Overall we are pleased with it.
**compare the 11kW with the 30kW gas boiler that usually gets put in houses half the size of ours. The gas boiler in our rented semi could heat the house from cold in a couple of hours. As well as the extra power rads have much lower latency than our underfloor particularly downstairs where the loops are under about 90mm of cement screed and flooring.
Last edited by: Manatee on Fri 7 Nov 25 at 23:11
|
|
Thanks, we wouldn't have underfloor and I guess some of the lag is because of that - rads would heat quicker but not as quickly as existing I imagine. I'd read about not oversizing it, and that's something I must remember when speaking to them. I have my consumption figures going back years but it isn't comparable as I'm thinking we'll have it on more anyway - but I suppose having a better grip on those figures wouldn't go amiss.
|
You shouldn't have the latency but you will almost certainly run at a fair bit lower flow temperature. That will be compensated by bigger rads and/or longer on-periods. So you house will still beat up more slowly.
I must say it's nice always to have a warm house. We don't do a night time set back but we do run the bedrooms at a lower temperature than downstairs. The rooms have individual stats controlling their loops. The unused bedrooms are currently set at about 18 which means their heat rarely comes on, as heat convects upstairs and is also circulated by the MVHR.
|
|
How much of the house do you want to heat? We have just installed a 4 kW air conditioner in our open plan living/dining/kitchen. While the main reason was to use the solar generated electricity to cool when it is 30° C+ outside, another benefit is being able to keep us warm without troubling the central heating.
|
I guess TRVs on the rads would do the same as room stats, as they would be a fairly large change I think.
I like the idea of always-on heating (though I don't feel the cold anywhere near as much as SWMBO) and I read that the bricks and floors can get warm so the house generally stays warm more efficiently.
I did look at a form of air conditioner when we were recently doing up the kitchen and it wouldn't have been a bad choice, and most likely loads cheaper than the ASHP route. A lot of the cold comes from the kitchen and without bothering with the detail here it's quite hard to prevent it. It was hard to tell how much improvement that would have brought to the rest of the house and in the end SWMBO decided we didn't want it!
|
>>I guess TRVs on the rads would do the same as room stats,
I think you're right.
|
TRVs are better than no TRVs but are stone age technology. A modern efficient heating system should include properly sited temperature sensors (6" from the floor is not optimal) and the ability to control individual rooms from an app:
- on/off time by room, modify timings for early/late starts
- set temperature for different times of day - eg: heat bedroom from 07.00-08.30 and 22.00-24.00
- switch on/off rooms not occupied - spare bedrooms. away on holiday, visitors etc
- even link to weather forecast to modify heating start time - eg: frosty (start early)
It is possible to retrofit better than TRV systems but potentially complex and expensive. If the system is being upgraded anyway this may be the time to do it. Alternatively one could rush around the house altering TRVs to suit.
All this is a compromise - a system which cannot deliver the control or performance you would ideally want, or spend possibly lots more to get something that largely meets contemporary standards. Individual circumstances are inevitably different so no "right" answer.
|
I have played with ZigBee TRVs which can be readily programmed using my Home Assistant, probably in a lot smarter way than the temp sensors you mention, so would probably go for those. They were about £15 each IIRC (now around £20). I could do automation on a room by room basis based on pretty much any variables really, even down to if the house or a room is solely occupied who it is - whether it's SWMBO who likes it hot or me who likes it cooler.
tinyurl.com/yc7svh5k
Must admit though, I don't think there is any great answer. Sometimes putting my room stat to 21 makes the room really hot and sometimes it doesn't. I've always assumed that's down to how warm you are when it starts, or something like that.
Last edited by: smokie on Mon 10 Nov 25 at 17:13
|
Whether you feel warm or cold is to a large degree subjective so setting a room to fixed temperature is not necessarily going to make the room occupant feel comfortable. Having a TRV that can easily be turned up or down by the room occupant can be the best and easiest solution. Unless you live in a 20 room mansion turning off the radiators in unoccupied room is hardly an onerous task.
Sometimes the simplest solution is best. You can have too many apps in your life.
|
Feeling warm is enhanced by the presence of actual radiant heat.
When we first moved in with the underfloor heating we missed the detectable heat from hot radiators. There is no way you can bask in radiated heat from a floor at 30 degrees C even though it might be maintaing the room temperature at 23. It's not even warm to the touch because it's below blood temperature.
We have got used to it now.
|
I'm sitting 'ere in shorts and T-shirt/hair vest, and it's 19c. HP set to fire up at 18c, which it doesn't do as I light the wood burner at 5pm.
:o}
|
I run a hybrid system with Tado App and controller, 8 Tado controlled TRVs, 2 wireless Tado Thermostats (at shoulder height) and some standard TRVs for less critical rooms. The whole house is also monitored using a RPi5 running NodeRed. The temperature profiles of the most used rooms typically have 8-10 changes per 24 hrs, and these can all be modified or turned off remotely using the tado app. No expensive subscriptions. I have not automated profile changes based on weather (actual,or forecast) as I prefer to rely on the subjective feel or planned occupancy.
I find auto geofencing a bit pointless, relying on turning everything back on remotely when I remember - usually as I turn into the drive!
Whilst it may not be cost effective on capital cost vs running savings, it does keep me out of the pub. SWMBO does not fully appreciate the workings but is allowed to control(overide) individual rooms, lower temperatures promote hibernation, with decreased energy consumption.
The house, 4bed detached, is oldish, not very well insulated (the loft has too much rubbish to entertain the thought of increasing the depth. I am convinced the 35 year accumulation of closed cardboxes reducing air circulation must have some merit.
I hope this post can point anyone thinking of going down this technological rabbit hole in appropriate directions.
|
Your description as a technological rabbit hole is extremely apt.
Myself when I feel cold I switch on my gas fired central heating “VIOLA”
|
A survey is now booked for next Wednesday. The phone guy said houses similar to mine are generally straightforward and unlikely to need additional insulation or work but the survey will confirm. He was generally pretty upbeat about the whole thing but then again he would be. I'm less so but if it comes in close to the quoted price it'll get serious consideration.
Having redecorated/remodelled much of the house over the past 2 year I feel I should have had it done before that - but it's too late for that now. If it's too intrusive I simply won't get it done.
|
So here's a question... I'm getting the usual negativity from SWMBO and I think I know the cause.
She'd be losing the airing cupboard capability in the hot water tank cupboard, as the cupboard is so small that the new tank would need to go in the loft.
I will research myself but I assume I could just have the old tank taken out, put in some more shelving and some sort of low level fan heater - has anyone done this, or similar? Tubular heaters seem to be the thing.
Last edited by: smokie on Wed 12 Nov 25 at 12:31
|
|
When we had the vented CH system replaced with a combi boiler, we had a tiny radiator and TRV fitted in the airing cupboard.
|
|
As I’m a cynical sceptic I think that salespeople always say what the potential customer wants to hear. Theirs a heating engineer on Facebook who’s opinion I respect, he seems to think heat pumps are noisy and inefficient.He’s had to remove a few over the years.
|
>> Theirs a heating engineer on Facebook who’s opinion I respect, he seems
>> to think heat pumps are noisy and inefficient.
>>
Well I've got one and I disagree with him.
|
>> Well I've got one and I disagree with him.
I was waiting for somebody to say that!!
|
|
I'm with ^this geezer and ours is 7 years old ... Some makes are noisier than others. Vaillant are Shhh, quite quiet.
|
Ours is not noisy, unlike the fanned flue gas boiler in the kitchen of the rental we lived in for 3 years.
We use 4500kWh per year for heating 2300 sq ft and DHW. I don't think it's as efficient as it could be but we've certainly had more than 4500kWh of heat out of it, which a gas boiler will not do.
I think there is such a thing as bad design and installation. And fitting one to an existing house using existing circuits needs to be well planned and executed.
I don't know why some are so bad but I suspect it's the circuits in a lot of cases. I've heard of one being fitted to a microbore system which I doubt very much would be able to provide enough flow.
|
|
Based on what I've read an oversized pump is also not good, I've read of a few people (I suppose out of hundreds or more) having them swapped out for smaller ones. One tends only to see the bad points on forums.
|
|
And once the gas boiler goes I can have the gas cut off, saving me a further £100+ in standing charge
|
>>Based on what I've read an oversized pump is also not good
Same with gas boilers.
>>And once the gas boiler goes I can have the gas cut off, saving me a further £100+ in standing charge
Yup, no gas here, although I miss not having a gas hob. Could have an induction hob, which are very good, but I'm not forking out for one of those if we move owse every 2 years :)
|
Just remembered the guy on Utube whose opinion I listen to.
It’s Roger Bisby, his Chanel is Skill Builder, worth a look.
|
>> Just remembered the guy on Utube whose opinion I listen to.
>> It’s Roger Bisby, his Chanel is Skill Builder, worth a look.
>>
For every utuber who rubbishs heat pumps, I can find you another who thinks they're great. I can only go by my own experience.
Last edited by: Robin O'Reliant on Tue 18 Nov 25 at 21:37
|
Air Source Heat Pumps ASHP - Terry
