ASHP - our architect negative about them

[Wadrian]

Hi everyone

 

For our self build, architect has suggested maybe having an GSHP instead of ASHP. He says customer feedback has been that ASHP have been noisy and struggling with getting to heat rads in colder days. I know ground source lot more expensive, but would you install ASHP - noise, lower temp etc

 

we are based in Manchester. Really keen to hear from anyone who has used ASHP and whether they are happy with it or if given the opportunity they would not have installed ASHP on their project.

[Conor]

If these are the architects own clients, maybe the issue is with the design of the build, not the ASHP? 🤣

 

 

 

You'll get dozens of replies endorsing ASHPs here, and few, if any for GSHPs.

[saveasteading]

If the architect is endorsing gshp then this is concerning, unless you live in a volcanic area or have a flowing aquifer. Manchester? No.

 

Tease them, they deserve it and need to learn.

 

Show us, dear architect, some gshp projects in the area.

Show us projected figures for our ground type.

Will you give any financial guarantees on  their performance?

BTW you must not spend any of my money on your research.

 

There are, or used to be, some honourable gshp contractors who would mostly advise that it was not suitable. Unfortunately they were pushed under by the others, one of whom perhaps has the ear of your untechnical  architect.

[JohnMo]

Sorry architect is talking utter rubbish.

 

A simple design ASHP (so no zones, no buffer) will do anything asked of it, if sized correctly.

 

You basically run it 24/7 on the lowest acceptable flow rate to keep house temp stable via weather compensation. Ideally size rads to a max design flow temperature of 45 or below. The lower the better.

 

The exact same rules above apply to a gshp.

 

Sub 5 degs outside the gshp will get a slightly better CoP generally, but the average winter temperature is generally higher than that. At warmer temps the ASHP will get a better CoP. Any savings aren't worth the additional costs of installing a gshp.

[JamesPa]

My suspicion is that the architect isn't confident about designing an ASHP based heating system so has taken the easy route out.  BTW I have encountered more than one 'M&E consultant' that is similarly clueless.   @johnmo is spot on the money with his comments above.

 

Having retrofitted an ASHP to my 1930s house (solid walls, with partial fabric upgrades, good loft insulation, uninsulated floors, 200 sq m, 7kW loss)  there is absolutely no way on earth I would fit a gas boiler if I were doing a new build, and I would frankly be reluctant to go back to a gas boiler if I were purchasing another 'second-hand' house.  Get an ASHP design right (basically follow the principles set out above and size it correctly), and you wont regret it.  Consider also if you want light cooling, an added bonus with the correct emitters.

Edited June 13 by JamesPa

[JohnMo]

Other thing I forgot to say - new build fit UFH - it's a no brainer. If a single storey it's easy. If a two storey size the UFH circuit to supply enough heat for the whole house heat loss. Then you need no heaters in bedrooms or fit fan coils in bedrooms for heat and cool and size UFH for just ground floor.

 

Then choose an ASHP that does cooling and use floor as a cooler. Ours has been on cooling mode since April. No condensation house temp nice and stable. 26 today, house at 21-22.

[nod]

We are in Woodplumpton near Preston if you ever fancy a visit And just finishing our second build 

 

I would say he’s half right Our Mitsubishi is noisier than the day it was installed But not near enough to bother anyone 

We have UFH to the GF and there is no difference between our previous build (Gas boiler) and this one 

We never used the Rads in the bedrooms on our previous and are unlikely to do so in this one But the radiators only run at 40 so don’t get hot like Rads on a gas system 60 I think So well suited to UFH 

 

A lot of the negative press is due to HPs being sold as a way of reducing bills While electricity is nearly four times the cost of gas They will remain more expensive to run Or in our case 

Very similar 

 

[Nickfromwales]

I’ve installed a Panasonic in a clients front garden, next to the boundary fence, and when on full wallop the lady next door asked if it would be noisy when it’s in use. I said it’s on right now, and she’s said “oh, I couldn’t tell”. Bingo. 
 

Another where the client could hear a boiler flue 30m away over the unit he was stood next to, again going full wallop as I was there switching these on for the very first time, the latter in dec and an outside temp of -2°C.

 

Your architect is saying the wrong thing, as regardless of where the heat comes from a kw is a kw, so a 16kw ASHP will produce………16kw, and a 16kw GSHP will produce……..16kw 🤷‍♂️🤦‍♂️🥹. 
 

So, they’re completely out of their depth and should stop giving you advice imho. They may be very good at designing houses, best they stick to what they know. 

 

[Redbeard]

Have you been in touch with People Powered Retrofit in Manchester? They may be able to put you in touch with householders with ASHPs.

 

My 2-penn'orth:

 

12 -17 years ago when the Energy Saving Trust did these field trials https://www.gov.uk/government/publications/analysis-from-the-first-phase-of-the-energy-saving-trust-s-heat-pump-field-trial#:~:text=The Energy Saving Trust's ( EST,83 households for Phase I. the CoPs for ASHPs were in some cases pretty grim. Now they are routinely pretty jolly good if the installation has been done well and insulation spec suits lower flow temps, so I would definitely go for ASHP. Indeed I do not have a field or space for boreholes so ASHP it will be. My HP will be a long way from the nearest neighbour, though, so all cases are not equal.

[Beau]

We have had a GSHP in our barn for 18 years with UFH and have just installed an ASHP in the farmhouse. The GSHP is much quieter for sure but the ASHP is not especially noisy but quite noticeable in our quiet rural location when it's working hard (Vaillant Arotherm 7). The farmhouse is only part insulated, has EWI, yet to receive loft insulation, no floor insulation, rads, and in spite of these things the ASHP has managed to heat it at a COP of over 4 since installation last autumn according to its stats. No problems keeping it warm thats for sure.

 

A new build  with all its insulation should be a doddle to heat with an ASHP

[Nickfromwales]

Most noisy heat pumps are ones which have been setup to run under duress, in a house it probably shouldn’t have been introduced to, or a cheap dogshit / budget unit bought from Ali-express.

 

Running heat pumps at their max temp threshold is bad darts, so imo max flow temps should be 35°C, but one we commissioned in 2022 had a flow temp of 26°C for space heating and a client complaining the house was a bit too warm and could we make it a bit less aggressive!

 

Low temp heat sources need to be matched with dwellings which are sympathetic to them. Or stay on gas. 

[Nickfromwales]

1 minute ago, Beau said:

The GSHP is much quieter for sure

Including the internal unit, or the external unit only? Where did you install the internal unit? 

[jack]

2 hours ago, Wadrian said:

For our self build, architect has suggested maybe having an GSHP instead of ASHP. He says customer feedback has been that ASHP have been noisy and struggling with getting to heat rads in colder days. I know ground source lot more expensive, but would you install ASHP - noise, lower temp etc

 

we are based in Manchester. Really keen to hear from anyone who has used ASHP and whether they are happy with it or if given the opportunity they would not have installed ASHP on their project.

Welcome.

 

Is it his customers who have complained about noise and performance, or is he repeating the Daily Mail's opinion?

Agreed GSHP is a lot more expensive. Even assuming you have the space for a GSHP, chances are it'll cost at least £10k more than an equivalent ASHP. They're also rarely specced in the UK so there isn't much knowledge about them in the industry. For that reason, from a performance perspective, I think installing a GSHP is as big a risk as installing an ASHP. Having too small a field (or bore), or burying loops at the wrong depth, or if you have ground that is sandy and often dry - any of these factors can lead to poor performance.

 

We've had a 5 kW ASHP on our new build for nearly 10 years. It hardly makes any noise and has had no problem at all handling heating and hot water for our ~290 m² house (admittedly PassivHaus-class insulation and airtightness, and we're in the South East, so not much energy required, but still).

 

3 minutes ago, Nickfromwales said:

but one we commissioned in 2022 had a flow temp of 26°C for space heating and a client complaining the house was a bit too warm and could we make it a bit less aggressive!

 

Until last winter, I'd been running ours with a base flow temp of 25°C, with a bit of weather compensation up to the high 20s in very cold weather. I now run the base temp a few degrees higher, and keep the heating period concentrated around the cheap period, so I use less energy in the expensive period.

[Beau]

11 minutes ago, Nickfromwales said:

Including the internal unit, or the external unit only? Where did you install the internal unit? 

It's all internal in a utility room except the ground loops. It's an  IVT Greenline C6 

 

I guess it does make a noise but its the noise of a circulation pump which seems to sort of blend in. The ASHP varies a lot but is a bit intrusive if you are outside when its working hard. Mind you most of us will not be outside on a cold winters day haha. Also its sized more for when our place is finished so is working harder than it will need to when I'm done. We also get a noise from the water running through the rads which we never had with the GSHP combined with UFH. It maybe a design issue but its quite an obvious noise 

Edited June 13 by Beau

[saveasteading]

54 minutes ago, nod said:

the negative press is due to HPs being sold as a way of reducing bills 

And probably sponsored by the pro oil/ climate change denying lobby.

 

I have oil at home. The boiler is broken and I am getting a new oil boiler, nk question.

A new house is being designed for ashp, even though no cheaper than oil at present.

 

For anyone new to the subject. Fundamentally, an ashp throws away air from which energy has been taken, and new air appears.

A gshp takes energy from the ground and it gets colder until it freezes.

I've represented people with gshp that cost much more to run than an electric fire, and got it replaced with ashp.

That developer won't be doing it again.

 

[nod]

9 minutes ago, saveasteading said:

And probably sponsored by the pro oil/ climate change denying lobby.

 

I have oil at home. The boiler is broken and I am getting a new oil boiler, nk question.

A new house is being designed for ashp, even though no cheaper than oil at present.

 

For anyone new to the subject. Fundamentally, an ashp throws away air from which energy has been taken, and new air appears.

A gshp takes energy from the ground and it gets colder until it freezes.

I've represented people with gshp that cost much more to run than an electric fire, and got it replaced with ashp.

That developer won't be doing it again.

 

It’s undeniable that GS running cost will be lower But you need to factor in the installation costs also and if your paying around £1500 per year in energy costs It will take a while 

[JohnMo]

34 minutes ago, Beau said:

noise of a circulation pump

Only pump for heating is in the ASHP itself, so manifold for UFH is total silent. Wife was stood by ASHP doing cooling today, unaware it was even on.

[Beau]

10 minutes ago, JohnMo said:

Only pump for heating is in the ASHP itself, so manifold for UFH is total silent. Wife was stood by ASHP doing cooling today, unaware it was even on.

I was referring to the GSHPs circulation pumps 

[JohnMo]

49 minutes ago, Beau said:

I was referring to the GSHPs circulation pumps 

I was referring to the only pump in the system with an ASHP. They don't have additional pumps required for a gshp. It also outside, not inside. There is zero noise inside.

 

1 hour ago, Beau said:

circulation pump which seems to sort of blend in

So plenty of noise

[Beau]

28 minutes ago, JohnMo said:

I was referring to the only pump in the system with an ASHP. They don't have additional pumps required for a gshp. It also outside, not inside. There is zero noise inside.

 

So plenty of noise

I'm just sharing my experience with both

 

In my limited experience the noise from our ASHP system is worse than our GSHP system. 

Edited June 13 by Beau

[saveasteading]

1 hour ago, nod said:

undeniable that GS running cost will be lower

Is that a misprint? 

Lower than what?

The heat produced is poor, and then it reverses to thaw itself.

The circulation pump is what it is, pumping round lukewarm water. There must be 2 of them though: one for the borehole and one for the house circuit.

My experience is that, installation cost disregarded, a gshp can cost as much to run as a resistance electric heater.

 

Re noise: yes a gshp is just a hum from a pump, whereas  the ashp also has the fan running in open air, producing motor noise and turbulence noise....but not much ...and it can be located to suit.

[marshian]

2 hours ago, Beau said: We also get a noise from the water running through the rads which we never had with the GSHP combined with UFH. It maybe a design issue but its quite an obvious noise 

Separate pump for rads? Turn pump speed down and or open up lockshields and run rads same temp as UFH if sized correctly

 

I hate system noise it’s a sure sign something is working harder than it should

[nod]

35 minutes ago, marshian said:

Separate pump for rads? Turn pump speed down and or open up lockshields and run rads same temp as UFH if sized correctly

 

I hate system noise it’s a sure sign something is working harder than it should

We’ve separate pump

As I say it doesn’t really matter to us 

I think that if you are running Rads 

You would simply treat them like UFH and leave them on and set a thermostat to the desired temp 

 

 

 

[Beau]

33 minutes ago, marshian said:

Separate pump for rads? Turn pump speed down and or open up lockshields and run rads same temp as UFH if sized correctly

 

I hate system noise it’s a sure sign something is working harder than it should

No just one pump and thats in the ASHP and its my understanding it controls the speed and I cant adjust it. 

 

The ASHP system is in the farmhouse and only has rads. All rads were installed with the ASHP so hopefully sized right. It's only the first few rads in the system that are noisy. I've seen several mentions of this problem in various places and I thought it happens because low temp rad systems need to have high flow rates. I've experimented with lockshield adjustment but the only way to make them quiet is to turn them off. 

 

[JohnMo]

9 minutes ago, Beau said:

ASHP and its my understanding it controls the speed and I cant adjust it. 

 

4 hours ago, Beau said:

Vaillant Arotherm

They generally run circulation pump at a fixed speed and speed is adjustable via the controller. Believe they actually run on a moving dT to ensure long cycle time, but with a fixed (user/installer adjustable) pump speed. So maybe the pump.is just running way to fast and hence the noise.