UPDATED: Air Source Heat Pumps/Air Con - Full Info & Guide, is it cheaper to run than mains gas?

Gerry1

GGSid said:

Running costs even at a claimed COP of >4 was more expensive than oil.

Has anyone ever achieved a COP of more than 4 from an ASHP?

matelodave

I doubt it very much although it depends how and when you measure it.

A bit like MPG in a car. Drive it gently and you can get very good MPG but drive it hard and it drops dramatically but what counts is the overall average

Cardew

Gerry1 said:

GGSid said:

Running costs even at a claimed COP of >4 was more expensive than oil.

Has anyone ever achieved a COP of more than 4 from an ASHP?

The only trial results I have seen were the Energy Saving Trust(EST) 12 month trials in 2010/11 and 2012/13.

They conducted a trial of 29 ASHPs(Air to water) and the results were little short of a disaster and attracted considerable adverse publicity in the media. The links to the detailed trial reports now do not work but from memory the average SYSTEM COP for the 29 ASHPs was 2.2; several were 1.6 and the highest 3.0.

This wasn't some cobbled together trial by EST as this quote from the report indicates:

The Energy Saving Trust would like to thank our partners, who have made this field trial possible:
Government organisations
The Department of Energy and Climate Change
The North West Regional Development Agency
The Scottish Government
Manufacturers
Baxi Group
Danfoss UK
Mitsubishi Electric
NIBE Energy Systems
Worcester Bosch

Specialist heat pump contractors
Earth Energy Ltd
Energy suppliers
British Gas
EDF Energy
E.ON Engineering UK
NIE Energy
RWE npower
Scottish Power Ltd
Scottish & Southern Energy PLC
Technical consultants
EA Technology Ltd
Energy Monitoring Company
Gastec at CRE Ltd
The Open University
Energy Saving Trust project team:
Simon Green, Project Director
Jaryn Bradford, Project Manager

“The Department of Energy and Climate Change(DECC) is very pleased to support the Energy Saving Trust’s field trials into heat pump technology. Field trials such as these are a
valuable way of establishing true performance in situ, as opposed to in the laboratory, and provide useful insights as to how performance may be improved. This is beneficial for industry, householders and the Government. DECC considers that heat pumps have an important role in achieving Government policies to reduce CO2 emissions”

In keeping with the Energy Saving Trust’s work throughout Europe and the UK, the results of this first year of the trial have been peer-reviewed by leading EU heat pump experts, including the SP Technical Research Institute of Sweden, Planair (Switzerland)
and Germany’s Fraunhofer Institute, as well as UK stakeholders including the Energy Technologies Institute (ETI).

Because of those results a further 12 month trial was commissioned and the new average COP for all the ASHPs was 2.45 with the highest being 3.2.

I am not aware of any great improvement in the performance claimed by the manufacturers and not seen any authenticated trials. If anyone has such information can the please post details.

A long and often boring thread(Mea culpa) with a lot more information is here:

https://forums.moneysavingexpert.com/discussion/2968958/ashp-should-do-better-must-do-better/p1

matelodave

As you say, these results are now seven years old and I guess that the heatpump industry has probably matured a bit since then and hopefully a lot of the cowboys will have been weeded out especially as the up front grants were ceased. Grants always seem to attract those who wish to make a fast buck - including councils and housing associations who get sucked into schemes which can be totally inappropriate either for their situation or even their clientele.

It's a shame that another decent trial or review doesn't seem to have happened to actually evaluate  the situation as it is now compared to what it was then - possibly with a bit more education, both with suppliers, installers and most importantly consumers has improved the operational efficiency of systems. One would also have though that OFGEM would have a lot more data from active systems since the introduction of the RHI as many installations now have to send in Consumption and efficiency data so there must be some relatively up to date info around.

My system is now ten years old and RHI was based on a crude "deemed" COP of 2.5 and TBH I think is a bit better than that but I don't have a heat meter to properly evaluate it. However a lot of the newer systems do have that capability and can be remotely monitored but I suspect that most systems are just being installed and commissioned but then not "tuned" to maximise their efficacy or efficiency.

It's pretty obvious from a lot of the threads and posts on this forum than many people don't understand how to use them properly and so don't get the best out of them.

They aren't the answer in all cases (possibly most cases) and I really do wonder what is going to happen when there's a wholesale shift towards them when the anti gas boiler and fossil fuel brigade get their way,

Cardew

Both EST reports stressed your point about owners unable to operate the systems correctly. However, particularly for the second trial, all the manufacturers were allowed to set up, and in some cases replace their ASHPs, and the results giving an average system COP of 2.45 were IMO disappointing. Defrosting and the need to provide domestic hot water hotter than the 'ideal' 30-35C have been described as the Achilles heel of heat pumps.

If heat pump technology has improved, surely the manufacturers would be clamouring for the Government to commission trials to demonstrate this improvement. However this quote from the Renewable Energy Hub's A Complete Guide to Heat Pumps in 2020 isn't encouraging:

'Ground source heat pumps tend to have an efficiency of between 2.5 and 3 (that is, 3 units of heat generated per unit of power needed to drive the system). Air source heat pumps can be slightly less efficient, with an average efficiency of between 1.5 and 3. However it must be noted that these figures are increasing as technologies advance and it is likely that manufacturer’s claims on a products’ COP will be very much a ‘best case scenario’.

System efficiency is dependent on other factors, however, such as the quality of the installation, the system owner’s competency in maximising the system output, and the property’s energy needs and efficiency.'

Another important point that is ignored in any comparison of running cost is the need for an ASHP to run very long hours or 24/7. Most people with gas/oil CH who are out all day have their heating to go off while they are away and come on say 30 minutes before they return - to a warm house. Similarly at night, the heating goes off and comes on before people get out of bed. With a ASHP this is not possible; it takes too long to raise room temperature.

So if a house with gas CH uses, say, 12,000kWh pa for the house to be at a suitable temperature when the occupants are in the house(and not in bed) an ASHP will use more than 12,000kWh to achive the same temperatures.

At the moment electricity is about 5 times more expensive than gas.  There are going to be huge problems if the Government make Heat Pumps compulsory

jonno147

Hi all - HNY.
I've recently had a survey done by E.ON for the suitability of my home as one of 250 in my area to have a FREE ASHP system fully installed, New hot water tank and radiator upgrades for free, A seven-year manufacturer’s warranty, Free post installation support; including your first annual heat pump service and breakdown cover for 1 year & Free smart heating controls and a heat pump monitoring package, all in the name of a greener more efficient heating system roll out the government are encouraging, under the Electrification of Heat Programme.

I currently have a Gas Central Heating system, with a combi-boiler, which is 15 years old and creaking a little.

From reading earlier posts, which I'm grateful to you all for sharing and providing advice, it appears that the ASHP is far from being a cheaper alternative to run than GSH.

Before I make the final decision, I was after your advice as to whether getting the ASHP system free is a worthy enough benefit in the long term to the replacement of a boiler and sticking with Gas.

Also, would an ASHP add any value to a property?

Appreciate any advice.

Regards, Jonno

richardc1983

jonno147 said:

Hi all - HNY.
I've recently had a survey done by E.ON for the suitability of my home as one of 250 in my area to have a FREE ASHP system fully installed, New hot water tank and radiator upgrades for free, A seven-year manufacturer’s warranty, Free post installation support; including your first annual heat pump service and breakdown cover for 1 year & Free smart heating controls and a heat pump monitoring package, all in the name of a greener more efficient heating system roll out the government are encouraging, under the Electrification of Heat Programme.

I currently have a Gas Central Heating system, with a combi-boiler, which is 15 years old and creaking a little.

From reading earlier posts, which I'm grateful to you all for sharing and providing advice, it appears that the ASHP is far from being a cheaper alternative to run than GSH.

Before I make the final decision, I was after your advice as to whether getting the ASHP system free is a worthy enough benefit in the long term to the replacement of a boiler and sticking with Gas.

Also, would an ASHP add any value to a property?

Appreciate any advice.

Regards, Jonno

Running costs for gas is cheaper than an ASHP purely based on price per kwh of gas vs electric. An ASHP doesn't add value as such as I found out myself when I was considering selling my home. For some the benefit of cooling may be seen as a bonus but many are not interested. On the other hand a "new heating system" with warranty will add value. 

Hermann

richardc1983 said:

jonno147 said:

Hi all - HNY.
I've recently had a survey done by E.ON for the suitability of my home as one of 250 in my area to have a FREE ASHP system fully installed, New hot water tank and radiator upgrades for free, A seven-year manufacturer’s warranty, Free post installation support; including your first annual heat pump service and breakdown cover for 1 year & Free smart heating controls and a heat pump monitoring package, all in the name of a greener more efficient heating system roll out the government are encouraging, under the Electrification of Heat Programme.

I currently have a Gas Central Heating system, with a combi-boiler, which is 15 years old and creaking a little.

From reading earlier posts, which I'm grateful to you all for sharing and providing advice, it appears that the ASHP is far from being a cheaper alternative to run than GSH.

Before I make the final decision, I was after your advice as to whether getting the ASHP system free is a worthy enough benefit in the long term to the replacement of a boiler and sticking with Gas.

Also, would an ASHP add any value to a property?

Appreciate any advice.

Regards, Jonno

Running costs for gas is cheaper than an ASHP purely based on price per kwh of gas vs electric. An ASHP doesn't add value as such as I found out myself when I was considering selling my home. For some the benefit of cooling may be seen as a bonus but many are not interested. On the other hand a "new heating system" with warranty will add value. 

I suspect the system being offered will be the Air to Water type so no cooling/air conditioning available.

Hermann

jonno147 said:

Hi all - HNY.
I've recently had a survey done by E.ON for the suitability of my home as one of 250 in my area to have a FREE ASHP system fully installed, New hot water tank and radiator upgrades for free, A seven-year manufacturer’s warranty, Free post installation support; including your first annual heat pump service and breakdown cover for 1 year & Free smart heating controls and a heat pump monitoring package, all in the name of a greener more efficient heating system roll out the government are encouraging, under the Electrification of Heat Programme.

I currently have a Gas Central Heating system, with a combi-boiler, which is 15 years old and creaking a little.

From reading earlier posts, which I'm grateful to you all for sharing and providing advice, it appears that the ASHP is far from being a cheaper alternative to run than GSH.

Before I make the final decision, I was after your advice as to whether getting the ASHP system free is a worthy enough benefit in the long term to the replacement of a boiler and sticking with Gas.

Also, would an ASHP add any value to a property?

Appreciate any advice.

Regards, Jonno

I'd suspect that if anything it would devalue the property as it is more expensive to run, a novel system that's not understood and a new way of 'running' the house needs to be learnt. Perhaps in time that will change and if the systems become more main stream it will be more readily accepted.

I have no evidence to support that though, just my own thoughts. Perhaps the best way to judge the impact on house price would be to ask a few local estate agents.

Mikeeuropa

jonno147 said:

Hi all - HNY.
I've recently had a survey done by E.ON for the suitability of my home as one of 250 in my area to have a FREE ASHP system fully installed, New hot water tank and radiator upgrades for free, A seven-year manufacturer’s warranty, Free post installation support; including your first annual heat pump service and breakdown cover for 1 year & Free smart heating controls and a heat pump monitoring package, all in the name of a greener more efficient heating system roll out the government are encouraging, under the Electrification of Heat Programme.

Wouldn't it just be great if these schemes were actually run in situations that made sense, where there was a real need. Like in areas that are off the mains gas grid for example. ASHPs simply can't compete on cost (installation or running) against mains gas as I pointed out in an earlier thread with the information here https://nottenergy.com/resources/energy-cost-comparison/

I saw a similar (or maybe the same) scheme advertised for applicants on the Energy Saving Trust website I think it was, so applied only to be told this was only being run in the South East. Now I've got nothing against people in the South East but the area in general has the lowest fuel poverty in the country, and is probably, on average a rather affluent area compared to many other regions of the UK.

This is a great offer for those who have no mains gas, and/or can't afford to replace that aging, inefficient, carbon generating oil boiler or the coal burning open fire with back boiler. Unfortunately they're not the ones who are going to get this free gift! Yes it may cost more to run than what it replaced but it would take a good few years to offset the £7k or more to replace that old oil boiler.

It annoys me that it's just a box ticking exercise probably so that E.On can meet it's eco obligations or the government can make some great claim about how green it is.

Sorry, rant over. 😁