Discuss ASHP - Godsend or the devils spawn? in the Renewables area at Plumbers Forums

gmartine

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I realise not many have a sub to Telegraph (neither do I) but this is the article in full. As for the statement by BG, I haven't corroborated it but it seems an odd one as their domestic ASHP assessments should be based on science and maths rather than a hunch or hoodoo. Saying that, I suppose the money back offer is the Victar Kiam of marketing and been made to placate an uncertain public.



So, you want to do your bit for the environment, and you took the Government at its word when it told you that ditching your perfectly well-functioning gas boiler for a heat pump is the way to go. But what do you do if you can’t find an engineer prepared to install one of the devices in your home because, in all honesty, they know it wouldn’t actually keep you warm?

British Gas has come out this week and stated what has doubtless been obvious for a long time to some homeowners who did take the plunge: that a standard heat pump runs at water temperatures which are too low to heat many properties. From now on, says the company, it will only agree to install a heat pump if it is convinced that it will succeed in getting the property up to a target temperature on the coldest days. If any of the heat pumps it installs fail this test, it says it will refund the money.

Fair enough, but that will mean millions of homes cannot have a heat pump installed by British Gas. There are eight million homes in Britain which have solid walls and which, as a result, are hard to bring up to required insulation standards at a reasonable cost. If other companies follow British Gas’ example, the Government will have no hope of achieving its target of retro-fitting 600,000 homes a year with a heat pump by the end of this decade. British Gas has just thrown a very large spanner into the Government’s net zero ambitions.

I don’t want to sound negative. I would much rather heat my house with an electric heat pump than its existing, smelly oil-fired boiler, and I would have made the switch years ago if I could be convinced it would keep the property warm. But to judge by the experience of many people, the air-source heat pumps being marketed en masse at the moment simply aren’t up to the job. They are an effective way of raising the temperature in your home when you don’t really need it to be heated, but if you live in an old property, and you have no other form of heating, you are likely to find yourself shivering on the coldest days.

There isn’t a lot of heat to extract from the air when it is minus 10C outside. There is more heat to be found underground, but to tap into that requires a far more expensive and space-consuming ground source heat pump. To spend £10,000 on a heat pump which turns out only to be effective as background heating seems a poor deal when you can buy a gas boiler which will do the whole job for a fifth of the price.

True, experiences vary, as indeed do people’s assessment of the work achieved by their heat pump – one of the biggest enthusiasts for heat pumps that I know also has a great oil-fired Aga in his home. But it seems to me that if heat pumps really are going to heat our homes in future the technology still has some way to develop. It is possible, even now, to buy a heat pump which chucks out water at similar temperatures to a gas boiler – but there is a big price to pay in terms of cost and efficiency. Maybe the technology will improve and costs will fall, but British Gas’ intervention this week should sound a warning to the Government – it is never a good idea to set targets before you are sure that technology is sufficiently advanced to allow them to be met.

 
I think it was down to them price matching installation quotes on rubbish designs

It’s one of them I think the gov has gone arse about face again should of made it law for new builds only but that’s another story with quality of build and insulation which I blame bc for
 
Recently met with a customer that had an ASHP installed last year in a reasonably well-insulated 1960s/1970s house to replace resistive electric heating. He is extremely happy with it. I suppose even if such systems run at a COP of 1 in cold weather, they will outperform old gas boilers and electric heating for much of the heating season.

Having myself had a recent run-in with a local authority Planning department that frankly couldn't give a toss about heat poverty and whose main priority is to be seen to be keeping the (squalid) housing in a 'conservation area' looking the same because, after all, the local authority doesn't have to live in those houses, I think the problem is likely to be getting the nation's insulation up to scratch. Given the cost of a heat pump is going to be considered affordable, I think virtually ANY house can be equally affordably insulated properly to the standard a heat pump installation would require.

The only thing I don't understand is why we didn't insulate properly years ago. I have a book from 1983 which explained how to do it back then (and which didn't get too many things wrong) and it isn't, technically speaking, that hard to do, though we have a lack of skilled tradesmen and political will.

The article sounds very much like another dig at a "new" technology to try to confirm the already entrenched opinions of readers that it is a bad idea and make them feel happy : note the -10°C bit which isn't exactly a mean EAT for most UK houses, and, as Shaun says, any half-decent installer would size the system properly. The irony, of course. is that the technofix of installing heat pumps has never been the primary go-to solution of anyone in the green movement who actually knows what he/she is talking about, however welcome the contribution heat pumps are able to make .
 
Recently met with a customer that had an ASHP installed last year in a reasonably well-insulated 1960s/1970s house to replace resistive electric heating. He is extremely happy with it. I suppose even if such systems run at a COP of 1 in cold weather, they will outperform old gas boilers and electric heating for much of the heating season.

Having myself had a recent run-in with a local authority Planning department that frankly couldn't give a toss about heat poverty and whose main priority is to be seen to be keeping the (squalid) housing in a 'conservation area' looking the same because, after all, the local authority doesn't have to live in those houses, I think the problem is likely to be getting the nation's insulation up to scratch. Given the cost of a heat pump is going to be considered affordable, I think virtually ANY house can be equally affordably insulated properly to the standard a heat pump installation would require.

The only thing I don't understand is why we didn't insulate properly years ago. I have a book from 1983 which explained how to do it back then (and which didn't get too many things wrong) and it isn't, technically speaking, that hard to do, though we have a lack of skilled tradesmen and political will.

The article sounds very much like another dig at a "new" technology to try to confirm the already entrenched opinions of readers that it is a bad idea and make them feel happy : note the -10°C bit which isn't exactly a mean EAT for most UK houses, and, as Shaun says, any half-decent installer would size the system properly. The irony, of course. is that the technofix of installing heat pumps has never been the primary go-to solution of anyone in the green movement who actually knows what he/she is talking about, however welcome the contribution heat pumps are able to make .

I went to a new ish detached house around 2010 cored a hole for a flue as boiler was getting moved no cavity wall insulation this was in a utility the mind boggles
 
I might have a read but The author of the DT article is Ross Clark author of Not Zero: How an Irrational Target Will Impoverish You, Help China (and Won’t Even Save the Planet)

so he has form and motivation for keeping the sceptics sceptical and peddling misinformation.
Some of those on the right think net zero is one big Marxist conspiracy.

Living in a temperate climate the UK has never been that motivated or incentivised to improve the quality of housing stock where most insulation improvement schemes have been half hearted and half baked. That and mostly laissez-faire governments have allowed building standards and therefore costs to builders to be kept low.

@ Ric, yeah I live in an conservation area but enforcement is weak so I just went ahead with externally insulating my place anyway which is solid brick. It was built in the fifties and not particularly well so I had no qualms taking the risk and modernising it.
 
Practically speaking, heat pumps are thermally outperformed by oil or gas fired boilers which will allways produce their rated output.
Heat pumps seem to be rated on 7C/35C conditions, a 15kw nominally rated HP will give 14.5kw under these conditions but only 9.81kw at a OT temp of 0C and 9.06kw at -3C, one is also limited to the max sized single phase HP, maybe around 20kw? so not difficult to see the challenges in retrofitting to older buildings.

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Also you need to be above a 3 scop else it’s more efficient to go gas
 
Cheaper anyhow whatever about COPs, another factor I rarely see mentioned is defrosting which is a significant factor in running costs especially around here with relatively high humidity levels.
 
@ Ric, yeah I live in an conservation area but enforcement is weak so I just went ahead with externally insulating my place anyway which is solid brick. It was built in the fifties and not particularly well so I had no qualms taking the risk and modernising it.
I'd like it if enforcement weren't weak. It shouldn't be one set of rules for the law-abiding and another for the sensible people. There'd be a national outcry and perhaps the idiots in power would realise how pathetic and stupid these conservation areas really are. How about tax breaks for certain types of work, and free maintenance courses and advice if these areas are SO important to the national interest, rather than just making you pay £200 and submit drawings if you want to replace a fence.
 
Cheaper anyhow whatever about COPs, another factor I rarely see mentioned is defrosting which is a significant factor in running costs especially around here with relatively high humidity levels.
Yes, that was a big deal back in the day, which was the main reason one of the engineers (an actual engineer with an engineering degree) at the Centre for Alternative Technology was fairly anti ASHP when we discussed the matter 10 years ago. I looked at some more recent literature and it seems that is less of a problem with modern design.

I suppose the logical thing is that if conditions mean defrosting knocks the COP to less than 1, then you switch to resistive heating.

The point was supposed to be that heat pumps would be used with a very high level of low-carbon electricity and a retro-insulated building stock, but that doesn't seem to be happening. Onshore wind is half the cost of offshore, but a number of counties are very against, so we're paying the price for that.
 
I might have a read but The author of the DT article is Ross Clark author of Not Zero: How an Irrational Target Will Impoverish You, Help China (and Won’t Even Save the Planet)

so he has form and motivation for keeping the sceptics sceptical and peddling misinformation.
Some of those on the right think net zero is one big Marxist conspiracy.

Living in a temperate climate the UK has never been that motivated or incentivised to improve the quality of housing stock where most insulation improvement schemes have been half hearted and half baked. That and mostly laissez-faire governments have allowed building standards and therefore costs to builders to be kept low.

@ Ric, yeah I live in an conservation area but enforcement is weak so I just went ahead with externally insulating my place anyway which is solid brick. It was built in the fifties and not particularly well so I had no qualms taking the risk and modernising it.
The author, as you point out, is largely writing from a subjective viewpoint. He hasn't really researched the subject nor spoken with Installers at the "Coal Face" (now there's an analogy for renewables)!
 
He was an actual engineer PLUS he had an engineering degree, if that makes my meaning clearer.
I think the point being made to you is that you are implying is that dealing with Gas and Heat Pumps doesn't constitute an Engineer. I would say it would,if credentials were spread on the table. The length of training undertaken by those who done apprenticeships; advanced training beyond that; and even today with some really demanding courses being offered are all considered to upskilling. I suppose it's a subjective topic, if you feel you are then you are if you don't ... then sobeit
 
In the UK, 'engineer' is a vague courtesy title that anybody can use.

The engineering institutions have been complaining about this since the 1970s to my personal knowledge and probably before then. Their view seems to be that only their members, i.e. CEng, should be allowed to use the title.

In contexts where it matters, you just have to use a more specific title, e.g. 'fitters', 'technicians', 'instrument makers', 'pattern makers', 'machinists', 'programmers', 'engineering graduates', 'chartered engineers', 'train driver', etc.
 

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