Air-source heat pumps - are they good/crap?

Air-source heat pumps - are they good/crap?

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Discussion

Funk

Original Poster:

26,563 posts

216 months

Sunday 4th February
quotequote all
Am considering a property which has an air source heat pump - apparently suitably well-insulated etc to make the most of it along with underfloor heating for the downstairs while the upstairs has rads.

I've no experience of them but rightly or wrongly I immediately have some reservations which, in farirness, may well be unfounded. Are they a good idea? Costly to run? Slow to warm up a property compared to GCH? I can see how having UFH could be a good thing - concrete will absorb and hold the heat nicely for a while. The property doesn't seem to have solar fitted which to my mind would be a great way of offsetting some of the cost of running the ASHP?

If the ASHP is crap it doesn't look like there'd be any option to retrofit gas. I have GCH at the moment in a reasonably well-insulated property and pay peanuts for what little I need to I use (around £15-20/mo during winter months) so I'm a little hesitant about moving to a new(er) technology I have no experience or understanding of.

Should ASHP be of concern when it comes to how well it works, what it costs and maintenance compared with a gas boiler? I had a new boiler fitted about 9-10 years ago and touch wood it's been completely trouble-free - I have an inspection annually which costs about £50. How does ASHP reliability and servicing compare etc?

Is ASHP fantastic and everyone should be adopting it? Does it work best with solar (ie. should I put that in a budget for future installation etc)?

Andeh1

7,202 posts

213 months

Sunday 4th February
quotequote all
As long as the house is OK Insulated, and you research how to get the best of them there is nothing to worry about. We have one in a new well Insulated house and love it.


The problem with them is when utter numpties who do a straight swap with a gas boiler without researching them, then cry foul when their drafty uninsulated house stays cold.

Skyedriver

18,848 posts

289 months

Sunday 4th February
quotequote all
Andeh1 said:
As long as the house is OK Insulated, and you research how to get the best of them there is nothing to worry about. We have one in a new well Insulated house and love it.


The problem with them is when utter numpties who do a straight swap with a gas boiler without researching them, then cry foul when their drafty uninsulated house stays cold.
Basically, this^^
Plus people aren't told how to work them properly (or ignore the instruction because they know best).

There's a lot of HA property getting updated around here. They were previously on a THTC set up of two meters. They're still on two meters and getting charged the high meter rate.

Notsofastfrank

215 posts

202 months

Sunday 4th February
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r3g said:
As you'll see from reading the other thread, apart from the dozen or so members who don't want to admit they got duped by the sharp-suited *SHP salesman and lie about their true performance to make them feel better about it, the other 95% of it is sage warning to avoid them like the plague. If you are coming from instant GCH then you'll hate it as they don't work at all in winter below freezing and temps in the single digits mean that it will take about 3 days before producing something that's slightly more than tepid.

You will hear claims from the dupesters saying that theirs produces piping hot water no problem when it's minus 3 outside, but they conveniently omit to mention that in low temps the system calls the grid for juice to heat up the water with electric, so your electric bills through the winter will require you to take out a bank loan. They cost biblical amounts to run in the cold months, you know, when you actually need them.

Just forget it. It's a stupid 'eco' fad that makes the tree-huggers all warm and fuzzy but like everything 'eco' it is complete garbage and doesn't work. Get yourself on YT and search "does ASHP work", "the reality of ASHP" etc and you'll soon see for yourself. Make sure you filter out all the videos by heat pump installers/manufacturers and sponsored reviews.

The acid test to instantly know whether something works or not is this question : is there a government grant available for it? If the answer is 'yes', then you can rest safe in the knowledge it is st and to be avoided like the plague. If the stuff actually worked then people would be happily buying them in droves with their own money, without the government giving you £7500-9000 to install one. They aren't, because it doesn't.

Edited by r3g on Sunday 4th February 19:45
This is completely incorrect. We bought a new-build with ASHP (LG) 3 years ago. It works absolutely fine and the house is always warm in winter, regardless of how cold it gets (lowest overnight temperature this winter has been -6c). The house is 3000 square feet and we pay £110 pm with the assistance of 7kw of solar panels and a 5kwh battery, without the solar/battery the cost would be about £225 a month. Ours was not correctly installed when we moved in, we had a local specialist rectify this which the builder paid for. Since then it has broken down once due to a faulty board, which were all being replaced by the manufacturer. We were without the ASHP for 2 weeks, we were not prioritised as it was the summer and the solar provided hot water.
An ASHP does not heat up as fast as a gas boiler, but you soon get used to that. One thing you soon learn is not to let room temperature drop by more than 2c overnight when it is cold or it will take 7 to 8 hours to warm back up. Also if you ask the ASHP to work hard it becomes less efficient, and it is also less efficient in colder weather, however it continues to work fine in sub-zero temperatures.
Make sure the radiators are of sufficient output at 50c as that is the temperature your radiators will be, you can tell the system to heat the water to 55c but this will use a lot more electricity. Underfloor heating is great, no radiators on the wall and very comfortable.
The biggest negative to an ASHP is the ridiculously high cost of electricity, you even get charged VAT, whereas gas doesn’t, so much for the government’s green energy policy.
I would have no problem buying another house with ASHP, as long as it was correctly installed and the house was well insulated.

r3g

3,750 posts

31 months

Sunday 4th February
quotequote all
As you'll see from reading the other thread, apart from the dozen or so members who don't want to admit they got duped by the sharp-suited *SHP salesman and lie about their true performance to make them feel better about it, the other 95% of it is sage warning to avoid them like the plague. If you are coming from instant GCH then you'll hate it as they don't work at all in winter below freezing and temps in the single digits mean that it will take about 3 days before producing something that's slightly more than tepid.

You will hear claims from the dupesters saying that theirs produces piping hot water no problem when it's minus 3 outside, but they conveniently omit to mention that in low temps the system calls the grid for juice to heat up the water with electric, so your electric bills through the winter will require you to take out a bank loan. They cost biblical amounts to run in the cold months, you know, when you actually need them.

Just forget it. It's a stupid 'eco' fad that makes the tree-huggers all warm and fuzzy but like everything 'eco' it is complete garbage and doesn't work. Get yourself on YT and search "does ASHP work", "the reality of ASHP" etc and you'll soon see for yourself. Make sure you filter out all the videos by heat pump installers/manufacturers and sponsored reviews.

The acid test to instantly know whether something works or not is this question : is there a government grant available for it? If the answer is 'yes', then you can rest safe in the knowledge it is st and to be avoided like the plague. If the stuff actually worked then people would be happily buying them in droves with their own money, without the government giving you £7500-9000 to install one. They aren't, because it doesn't.

r3g

3,750 posts

31 months

Sunday 4th February
quotequote all
Notsofastfrank said:
This is completely incorrect. We bought a new-build with ASHP (LG) 3 years ago. It works absolutely fine and the house is always warm in winter, regardless of how cold it gets (lowest overnight temperature this winter has been -6c). The house is 3000 square feet and we pay £110 pm with the assistance of 7kw of solar panels and a 5kwh battery, without the solar/battery the cost would be about £225 a month. Ours was not correctly installed when we moved in, we had a local specialist rectify this which the builder paid for. Since then it has broken down once due to a faulty board, which were all being replaced by the manufacturer. We were without the ASHP for 2 weeks, we were not prioritised as it was the summer and the solar provided hot water.
An ASHP does not heat up as fast as a gas boiler, but you soon get used to that. One thing you soon learn is not to let room temperature drop by more than 2c overnight when it is cold or it will take 7 to 8 hours to warm back up. Also if you ask the ASHP to work hard it becomes less efficient, and it is also less efficient in colder weather, however it continues to work fine in sub-zero temperatures.
Make sure the radiators are of sufficient output at 50c as that is the temperature your radiators will be, you can tell the system to heat the water to 55c but this will use a lot more electricity. Underfloor heating is great, no radiators on the wall and very comfortable.
The biggest negative to an ASHP is the ridiculously high cost of electricity, you even get charged VAT, whereas gas doesn’t, so much for the government’s green energy policy.
I would have no problem buying another house with ASHP, as long as it was correctly installed and the house was well insulated.
So despite labelling my post as being "completely incorrect" you've agreed with everything I said. Got it.

caziques

2,651 posts

175 months

Sunday 4th February
quotequote all
Notsofastfrank said:
I would have no problem buying another house with ASHP, as long as it was correctly installed and the house was well insulated.
This is the issue, correct installation.

Unlike a boiler, which can basically be chucked in and it will work OK, other factors such as water flow. controls, sizing, defrosting cycles, pipe sizing, radiator sizing and buffer tanks must be considered when a heat pump is fitted.

It would be very unlikely that a heat pump will perform OK simply by replacing a gas boiler.

Simpo Two

87,026 posts

272 months

Sunday 4th February
quotequote all
The only ASHP I'll be buying is in an aircon unit.

Notsofastfrank

215 posts

202 months

Sunday 4th February
quotequote all
r3g said:
So despite labelling my post as being "completely incorrect" you've agreed with everything I said. Got it.
I don’t see how I have, quite the opposite but I expect like most experts, you’ll be sure to have the last word. Have you actually had an ASHP in your home or are you just regurgitating sensationalist You Tubers?

Evanivitch

22,054 posts

129 months

Sunday 4th February
quotequote all
r3g said:
If you are coming from instant GCH then you'll hate it as they don't work at all in winter below freezing and temps in the single digits mean that it will take about 3 days before producing something that's slightly more than tepid.
I've see the same claims that condensing boilers don't work at 0C either...

finlo

3,840 posts

210 months

Sunday 4th February
quotequote all
Evanivitch said:
r3g said:
If you are coming from instant GCH then you'll hate it as they don't work at all in winter below freezing and temps in the single digits mean that it will take about 3 days before producing something that's slightly more than tepid.
I've see the same claims that condensing boilers don't work at 0C either...
They don't if the condensate pipe freezes up!

joestifff

819 posts

113 months

Sunday 4th February
quotequote all
Evanivitch said:
r3g said:
If you are coming from instant GCH then you'll hate it as they don't work at all in winter below freezing and temps in the single digits mean that it will take about 3 days before producing something that's slightly more than tepid.
I've see the same claims that condensing boilers don't work at 0C either...
We have it. 3 year old house. Very well insulated, proper install. Underfloor wet heating etc.

Ours works absolutely fine in very cold temps. We’ve had many days of sub zero over the years up North. Never been an issue.

However, we don’t have our heating come on and off on a timer. It comes on when a temp drops. You can’t let the house get too cold or it will take a long time to get back up. You have to change your mindset. A timed heat setting does not work in my opinion with ASHP, you have to be on it and compensate constantly.

You get used to the fact that radiators (we only have them upstairs) don’t get hot like GCH. They get warm at best. They do eat electric too. We also have a log burner. But have had them in GCH houses too. You don’t need one (our neighbours don’t) but it’s nice to have that instant heat if needed.

I don’t love ours. But I don’t see any issue. It does what it does.

I’d have chosen gas if we could. But no such thing round here.

In my opinion, you have to have a well insulated house. You really should have underfloor heating, and you have to change your mindset and not expect instant heat, and have it come on when it needs to. Not timed.

finlo

3,840 posts

210 months

Sunday 4th February
quotequote all
Surely having a log burner defeats the whole point of having a ASHP?

CoolHands

19,435 posts

202 months

Sunday 4th February
quotequote all
So you have to sleep roasting your nuts off cos you can’t let the house cool down

Evanivitch

22,054 posts

129 months

Sunday 4th February
quotequote all
finlo said:
Evanivitch said:
r3g said:
If you are coming from instant GCH then you'll hate it as they don't work at all in winter below freezing and temps in the single digits mean that it will take about 3 days before producing something that's slightly more than tepid.
I've see the same claims that condensing boilers don't work at 0C either...
They don't if the condensate pipe freezes up!
Precisely. There are nuances to things not working and some of it is the material of the building (I.e. losses greater than heating power), and equipment not functioning correctly.

I've experienced air to air heat pumps in Sweden at minus 26. They worked well, there were also electric heaters in the chalets, and their humidity is typically lower than hours.

cliffords

1,804 posts

30 months

Sunday 4th February
quotequote all
Crap

Equus

16,980 posts

108 months

Sunday 4th February
quotequote all
Notsofastfrank said:
An ASHP does not heat up as fast as a gas boiler, but you soon get used to that. One thing you soon learn is not to let room temperature drop by more than 2c overnight when it is cold or it will take 7 to 8 hours to warm back up. Also if you ask the ASHP to work hard it becomes less efficient, and it is also less efficient in colder weather, however it continues to work fine in sub-zero temperatures.
Make sure the radiators are of sufficient output at 50c as that is the temperature your radiators will be, you can tell the system to heat the water to 55c but this will use a lot more electricity. Underfloor heating is great, no radiators on the wall and very comfortable.
The biggest negative to an ASHP is the ridiculously high cost of electricity, you even get charged VAT, whereas gas doesn’t, so much for the government’s green energy policy.
Or, to say effectively the same things with the rose-tinting removed:

In direct comparison with a modern mains-gas* fired boiler, they are inflexible and no cheaper (possibly more expensive, depending on your use case) to run.

It's no good pretending that they aren't less flexible: they are. Whether or not you're willing to live with that is a personal decision, but let's not pretend it isn't a factor to be considered.

It's no good blaming electricity for being more expensive: it is. You might as well say that ASHP's would cost nothing to run if electricity was free. nuts

The fact is that electricity is much more expensive, per kW/h, and peoples' real world choices have to take that into account, too.



* If you're not on the mains network for gas, and your mainstream choices are limited to oil or lpg, they stack up a little better in terms of running costs.

Snow and Rocks

2,411 posts

34 months

Sunday 4th February
quotequote all
I always find it amusing when people say that an ASHP will be perfectly economical if you have a really well insulated house - feels a bit like saying a Range Rover V8 is affordable to run if you buy a house next door to your office.

Yes an ASHP might be viable in a really well insulated house but what would it cost to heat that same insulated house with a gas boiler? I'd put money on it being cheaper overall and you wouldn't have to deal with the inflexibility of the heat pump.

Chrisgr31

13,736 posts

262 months

Sunday 4th February
quotequote all
A colleague of mine has it and her electricity bill is virtually unaffordable. However the suggestion is that it is a faulty installation not that anyone can work out whats wrong with it.

cliffords

1,804 posts

30 months

Sunday 4th February
quotequote all
Snow and Rocks said:
I always find it amusing when people say that an ASHP will be perfectly economical if you have a really well insulated house - feels a bit like saying a Range Rover V8 is affordable to run if you buy a house next door to your office.

Yes an ASHP might be viable in a really well insulated house but what would it cost to heat that same insulated house with a gas boiler? I'd put money on it being cheaper overall and you wouldn't have to deal with the inflexibility of the heat pump.
This 100% agree.