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Air Source Heat Pumps
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There are other things to take into consideration too. Oftec regs for siting oil tanks are getting more expensive to meet. Then there is the hassle of deliveries - I know a family who let their tank get low over Xmas who had to relocate to grandparents houses as the earliest oil delivery they could get was 2 weeks away. At the end of the day it is down to personal preference. A new oil system to cover our needs would have only been slightly cheaper than my ashp system.0
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Also a most important point is that an ASHP needs to run when occupants are out at work and in bed.
An oil or gas CH system with water at up to 82C can be set to come on, say, 20 minutes before getting up in morning and also before returning from work. Most of the posts from(presumably) working occupants talk of having heating on for, say, an hour in the morning and 5 hours in the evening.
Not so an ASHP with water at 35C or so, as it cannot bring the property quickly up to the required temperature.
The proponents of ASHPs always talk of the COP as the main factor in running costs. 200kWh input giving 600kWh output etc. However an Oil/Gas CH system would not need anywhere like 600kWh to provide the same temperature - when it is required. A fact conceeded by the EST.
Can I clarify...
When you mention Gas CH above I take it what you actually mean is LPG Gas CH? If that is correct, which I guess it is as mains gas is almost never available in rural locations, would we not be correct in assuming that bottled LPG gas regardless of CH circulating temperature is the most expensive way possible to heat a property? Bulk LPG tanks may be slightly cheaper but come with punitive two year contracts typically increasing prices every quarter.
Assuming a low COP of 3.0, thought I get much better but will ignore that, surely you are not serious in comparing LPG to the assumed 3.1p per kwh? Not to mentioned the running costs are subsidised by the tax payer thanks to solar pv FITs/free leccy.
Please help as struggling here to understand how LPG gas is a contender to a heat pump...
PS Certainly LPG gas engineers report that most of their custom now comes from caravan parks as relieved home owners continue to switch to renewables...
PPS It may be of little interest but the ASHP only runs when the house is occupied but never during the night.
PPPS nande2000 - Agree, oil was not much cheaper as the wife would still have bought designer rads costing ££££'s, then siting a new tank with underdround pipes, all new DHW tanks, plumbing, boiler etc At that time when RHI promised it was £18,000 odd grant which made it a no brainer. Still only a few weeks to wait for RHI confirmation now.
It's been 10 years now since I had a large rural house outside Bristol and remember emptying a 1000lt tank in two months [no aga etc] then waiting ages for a fill in a freezing cold snap. Happy days, not...
PPPPS [getting boring]... Another benefit of heat pumps in they require almost no maintenance whereas oil/lpg owners either have to subscribe to questionable maintenance contracts or PAYG repairs/annual servicing. If unlucky enough to own an AGA/Rayburn the frequent service costs are eye watering.
PPPPPS [getting really boring]... Being electric only means no second standing charge/tank rental.
Anyway bored now
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Well, considering everything I've ever read and everyone I know who has an ASHP installation and uses it as the primary heating source in their main residential property .... that really did make me chuckle .....jeepjunkie wrote: ».... Assuming a low COP of 3.0 ....
.... thanks !!!
Z"We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
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jeepjunkie wrote: »Can I clarify...
When you mention Gas CH above I take it what you actually mean is LPG Gas CH? If that is correct, which I guess it is as mains gas is almost never available in rural locations, would we not be correct in assuming that bottled LPG gas regardless of CH circulating temperature is the most expensive way possible to heat a property? Bulk LPG tanks may be slightly cheaper but come with punitive two year contracts typically increasing prices every quarter.
Assuming a low COP of 3.0, thought I get much better but will ignore that, surely you are not serious in comparing LPG to the assumed 3.1p per kwh?
Please help as struggling here to understand how LPG gas is a contender to a heat pump...
...
To clarify:
I was pointing out that a major disadvantage of a Heat Pump is that it has to keep producing heat when the occupants are out of the house or in bed. i.e. 'wasted heat'
That disadvantage does not apply to oil or gas CH(either type - 'natural' or LPG)
People can do their own calculations on running costs on systems. There are so many factors to consider. If you feel that an ASHP is better for you than LPG you may well be correct - I believe you are retired and at home during the day??
On the subject of COP values. Certainly a COP of 3.0 is not low. Look at the EST trial of 29 systems.
https://forums.moneysavingexpert.com/discussion/2968958Or try this http://www.energysavingtrust.org.uk/...heat-pumps-PDF
The study was a year long and had 29 ASHP systems from a number of manufacturers.(who installed the systems)
It is quite a long report but of the 29 ASHP systems the annual COP for 19 of the systems was 2.2 or less(the highest number had a COP of 1.6). So if that is an average spread across 12
months - little wonder systems are struggling in this current weather. In fact with the requirement for wasteful defrosting cycles, it is quite easy to envisage a situation with some systems where there will be a COP of less than
1.0 and people would be better to switch off the ASHP and rely on Granny's old 1/2/3 bar fire!!!!!!
Just one achieved a COP of 3.0.
Incidentally how do you know that you achieve a COP 'much better' than 3.0. From earlier posts you couldn't measure the COP - has that changed?
Also the capital costs of an ASHP system are another huge disadvantage over, say, oil. - especially those who already have an oil CH system.
The average gas consumption in UK is 16,500kWh. So it is reasonable to assume that an oil CH would use the same. Thus just under 1,650litres costing approx £1,040. (Boilerjuice gives average price of 63p/litre today).
Assuming an efficiency of 85% an oil boiler will deliver 14,025kWh of 'useful heat'.
If an ASHP could deliver an annual COP of 3.0 it would need 4,675kWh to deliver the same 14,025kWh. At 12p/kWh that would cost £561.
Thus a saving of £480pa - however as explained above the 'wasted heat' reduces that saving considerably.
It seems quotes for an ASHP installation are at least £10,000. Lost long term interest rates on savings @ 3% would be £300, and a lot more if the money has to be borrowed.
Obviously that £10k+ would need to be reduced by whatever it cost to get an oil CH system up to scratch.
In conclusion I think that people should consider the above points when selecting a heating system.
P.S.
I know you are aware of the EST trial - I have included it for those who might not have seen the report.0 -
Well, considering everything I've ever read and everyone I know who has an ASHP installation and uses it as the primary heating source in their main residential property .... that really did make me chuckle ..... .... thanks !!!
Z
Not all heat pumps started life on the roofs of trucks
I aim to please
Cheers0 -
PPPPPPS: You forgot to mention no one can syphon off your electric as easily as your oil.
They're not for everyone, you have to weigh up the pros and cons,
for us it has worked out to be the right choice.
If/when the RHI kicks in, well, that's a game changer A pair of 14kw Ecodans & 39 radiators in a big old farm house in the frozen north :cool:0 -
Keeping this in the context of rural properties with no access to mains gas i.e. where heat pumps are like to be installed…
I was pointing out that a major disadvantage of a Heat Pump is that it hasto keep producing heat when the occupants are out of the house or in bed. i.e. 'wastedheat'
That disadvantage does not apply to oil or gas CH(either type - 'natural' or LPG)
Certainly in our case there is little wasted heat but... The vast majority on LPG and oil do not run their heating needlessly as is far too expensive to do so. So much so that the house is typically under heated.
People can do their own calculations on running costs on systems. There are so many factors to consider. If you feel that an ASHP is better for you than LPG you may well be correct - I believe you are retired and at home duringthe day??
Not retired unfortunately.
Incidentally how do you know that you achieve a COP 'much better' than 3.0.From earlier posts you couldn't measure the COP - has that changed?
Yes
Also the capital costs of an ASHP system are another huge disadvantage over,say, oil. - especially those who already have an oil CH system.
We were starting from scratch i.e. pretend there was no heating system to begin with so no not such a big difference with cheaper running costs and grants to boot.
The average gas consumption in UK is 16,500kWh. So it is reasonable toassume that an oil CH would use the same. Thus just under 1,650litres costing approx £1,040. (Boilerjuice gives average price of 63p/litre today).
Assuming an efficiency of 85% an oil boiler will deliver 14,025kWh of'useful heat'.
If an ASHP could deliver an annual COP of 3.0 it would need 4,675kWh todeliver the same 14,025kWh. At 12p/kWh that would cost £561.
Thus a saving of £480pa - however as explained above the 'wasted heat' reduces that saving considerably.
I’m too tired to go digging for figs right now but pay roughly £53pm for heating and hot water. LPG was £200pm with the bare minimum of use. If any heat is wasted at least I’m not wasting £147pm on LPG.In conclusion I think that people should consider the above points when selecting a heating system.
Totally agree0 -
PPPPPPS: You forgot to mention no one can syphon off your electric as easily as your oil.
They're not for everyone, you have to weigh up the pros and cons,
for us it has worked out to be the right choice.
If/when the RHI kicks in, well, that's a game changer
I did think of many other reasons but thought it best to button it 0 -
Do you honestlt think that the RHI will kick in for us ASHP users? - the government has procrastinated and back pedalled for so long I don't really think it will happen, or if it does the rules will be so onerous that it wont be worth it. I didn't choose to have mine because of the promise on the RHI but hoped it would be a bonus. I was fortunate to pay only 5% on my whole heating system as it was supplied as a complete renewable energy system, but I got no other incentives as we had it installed during one of many the gaps in the ever changing incentive schemes.
On another subject - we have changed our kitchen lighting to LED, so instead of 10 x 50watt GU10s we've now got 10x4watt GU10s. Saving 460 watts for every hour that they are on. They actually give a better spread of light and I'm hoping to save at least £50 a year just in the kitchen.Never under estimate the power of stupid people in large numbers0 -
Himatelodave wrote: ».... On another subject - we have changed our kitchen lighting to LED, so instead of 10 x 50watt GU10s we've now got 10x4watt GU10s. Saving 460 watts for every hour that they are on. They actually give a better spread of light and I'm hoping to save at least £50 a year just in the kitchen.
... and so you should, if the kitchen lights were/are on for an average of ~2.5Hrs/day .....
HTH
Z"We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle0
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