ASHP – Should do better - Must Do Better

mekj

Thanks Cardew for highlighting the dubiety of the claims made by what would appear to be most of the ASHP industry. And also for some of the examples contributed by those with actual experience of installed systems.

I'm about to start a total refurb of an old stone property which will have very good insulation installed all round, new windows etc but with a relatively clean page for heating/DHW.
I was attracted to the ASHP concept and did considerable research into the various manufacturers and appliances. Being in Scotland we need to allow for the possibility of temps approaching -20.
Having read your thread and looked at the discrepancies between manufacturer claims and actual operation further backed up by some examples from actual users it would seem very rash to consider ASHP as a realistic alternative to gas both in terms of cost (installation and running) but more so reliability, the possibility that a unit might not cope with the minus temperatures is not a risk worth taking.
So back to the drawing board and reconsidering gas.

Thanks again for the thread, combined with some other negative comment elsewhere you helped me to reach a final decision on ASHP.

lovesgshp

Lardconcept.
Please give more info on your bungalow size, plus the ASHP size you have been quoted for. 13K is high, unless you are getting to 14kkwh output units

rdc1969

Question about ASHP - I'm looking at getting a system installed at the moment to replace an ancient oil fired boiler as I cannot get gas mains installed cheaply, probably looking at the Mitsubishi Ecodan W85. I have seen a few of the units on ebay recently for a fair bit less than the RRP and wonder if you can still get MCS commissioning on these units once they are installed or do they have to be supplied by the company doing the MCS commissioning such as Ice Energy?

Cheers

TiredGeek

Cardew wrote: »

£13,000 for an ASHP system is just a joke. You can invest that sum in a long term notice account at 4% after Tax, and that produces £520 a year. Borrowing the money costs even more.

ROFL
Looks like I fell for it then with an initial outlay of £14,000, in November '08! Christ knows what it'd cost now......
BTW, where are you getting 4%, it's not easy in the UK right now
Though I may actually have been better simply burning £5 notes to keep warm. LOL

Cardew

TiredGeek wrote: »

ROFL
BTW, where are you getting 4%, it's not easy in the UK right now

Several places give a 'safe' 5%(4% after tax) for long term(5 year) savings: AA, Birmingham Midshires.




http://www.moneysavingexpert.com/savings/savings-accounts-best-interest

Cardew

scotmac1 wrote: »

I would never, ever go for gas after what happened to friends . http://news.bbc.co.uk/2/hi/uk_news/scotland/985173.stm

I wonder why you would post about something that happened 11 years ago.

I suspect that for every gas explosion fatality, there are dozens killed by electricity in the home - electrocuted, electric appliances/wiring causing fires etc.

semo

mekj wrote: »

Thanks Cardew for highlighting the dubiety of the claims made by what would appear to be most of the ASHP industry. And also for some of the examples contributed by those with actual experience of installed systems.

I'm about to start a total refurb of an old stone property which will have very good insulation installed all round, new windows etc but with a relatively clean page for heating/DHW.
I was attracted to the ASHP concept and did considerable research into the various manufacturers and appliances. Being in Scotland we need to allow for the possibility of temps approaching -20.
Having read your thread and looked at the discrepancies between manufacturer claims and actual operation further backed up by some examples from actual users it would seem very rash to consider ASHP as a realistic alternative to gas both in terms of cost (installation and running) but more so reliability, the possibility that a unit might not cope with the minus temperatures is not a risk worth taking.
So back to the drawing board and reconsidering gas.

Thanks again for the thread, combined with some other negative comment elsewhere you helped me to reach a final decision on ASHP.

The problem with ASHP systems in the UK is that there isn't that much knowledge/skill consistently across the land for domestic installations. The technology is still seen as more suitable for big businesses/buildings.

Another problem is that most horror stories come from users that use hydrofluorocarbon systems for 65 degrees C hot water and on installations that were designed for gas powered systems. The Japanese have been using ecocute (R744 heatpumps) for their hot water for over a decade. The only such system I've found in the UK is the Sanyo CO2 ECO and apparently it can cope with -20. And whereas most ASHP systems on the market here in the UK struggle to raise water temperatures up to 60 degrees C, ecocute systems can cope with 70 and up to 90 for professional systems. Hitachi make a system that can provide instant hot water (like from a combi boiler).

I am thinking of getting a Sanyo CO2 ECO but I've been quoted £6k for the 4.5kW version (excluding installation) so not sure if I can afford it yet. Will report back if I end up getting it though

Cardew

semo wrote: »

The problem with ASHP systems in the UK is that there isn't that much knowledge/skill consistently across the land for domestic installations. The technology is still seen as more suitable for big businesses/buildings.

Another problem is that most horror stories come from users that use hydrofluorocarbon systems for 65 degrees C hot water and on installations that were designed for gas powered systems. The Japanese have been using ecocute (R744 heatpumps) for their hot water for over a decade. The only such system I've found in the UK is the Sanyo CO2 ECO and apparently it can cope with -20. And whereas most ASHP systems on the market here in the UK struggle to raise water temperatures up to 60 degrees C, ecocute systems can cope with 70 and up to 90 for professional systems. Hitachi make a system that can provide instant hot water (like from a combi boiler).

I am thinking of getting a Sanyo CO2 ECO but I've been quoted £6k for the 4.5kW version (excluding installation) so not sure if I can afford it yet. Will report back if I end up getting it though

There are loads of heat pumps(all?) marketed in UK that have impressive COP figures that should cope with even the coldest winter when DHW is set to 40C-45C.

The problem as many people have discovered is that many systems fail to achieve anything like those figures. (read earlier in thread)

4.5kW to cover space heating and high temperature domestic hot water is pretty small.

£6k plus fitting costs - say £8k? is a lot of money. That invested after tax will yield £320 pa.

semo

Cardew wrote: »

There are loads of heat pumps(all?) marketed in UK that have impressive COP figures that should cope with even the coldest winter when DHW is set to 40C-45C.

The problem as many people have discovered is that many systems fail to achieve anything like those figures. (read earlier in thread)

4.5kW to cover space heating and high temperature domestic hot water is pretty small.

£6k plus fitting costs - say £8k? is a lot of money. That invested after tax will yield £320 pa.

I think you missed the point of my post. I have not read of a single topic discussing an ecocute system in a UK domestic environment. The technology is expensive because it is so new here in the UK. R410a refrigerants just don't cope all that well with low temperatures for water heating. I think the EST should make a new study and this time include R744 systems. Sanyo also make a 9kW system. Costs are still high but it would be interesting to know how these newer systems cope in the UK, compared to the current Ecodan, etc. installations

Cardew

Sorry, I did miss your point and agree that it would be good to get some independant tests carried out.

Without comprehensive and lengthy tests of the system(defrost cycles etc) there is just no way a customer can determine if an installed system is delivering the claimed performance.

Despite my scepticism in this thread, I feel that future developments in technology have every possibility of making ASHPs the natural choice for houses without gas.