Oil boiler sizing - is bigger better?

albyota

Anybody thinking of installing any type or make of heat pump should visit the following websites

http://www.realassurance.org.uk/consumers

http://www.microgenerationcertification.org/consumer

albyota

Cardew wrote: »

Just been reading the latest WHICH on-line and found this quote:




Heat pump trial - key findings




The study found that only 13% of all sites in the trial achieved a level of efficiency the EST considers to be a 'well-performing' system, with the rest scoring below this benchmark.

do you mean this.....?

http://www.which.co.uk/energy/creating-an-energy-saving-home/guides/ground-source-heat-pumps-explained/ground-source-heat-pumps---trial-results/

Let the readers decide.......!

Cardew

Agreed let them decide.

The point is that on a year long trial with manufacturers involved, to conclude that only 13% performed well, is at odds with your contention that 98% 'have been spec'd and fitted correctly, but no one ever reports good news.....!'
.

The other point is the IMO horrendous cost of these systems; with many costing over £10,000. If someone invests £10,000 in a long term savings account it will produce £450 a year before tax(£360 after tax if not in an ISA) That will go a long way toward the average properties' heating/HW bill.

[Deleted User]

Cardew wrote: »

Agreed let them decide.

The point is that on a year long trial with manufacturers involved, to conclude that only 13% performed well, is at odds with your contention that 98% 'have been spec'd and fitted correctly, but no one ever reports good news.....!'
.

The other point is the IMO horrendous cost of these systems; with many costing over £10,000. If someone invests £10,000 in a long term savings account it will produce £450 a year before tax(£360 after tax if not in an ISA) That will go a long way toward the average properties' heating/HW bill.

Sorry don't agree...

Let's get this in perspective...

£10k is a only few months salary and when RHI starts in Oct 2012 on top of the £850 RHI premium payment leaving £10k in a bank account for a few quid in interest is just madness. The alternative is the ongoing horrendous cost of oil and LPG with unfair contracts...

£450 would pay for a months oil in winter which is only a tad below my predicted total electricity [inc ASHP] useage for 12 months. Ok we have PV but if I'm right you quote the saving to be £70ish so not a big factor here.

ASHPs have come along way and all Joe punter needs to do is a little research first. Of course despite this there will always be cases where things go wrong and ASHPs are no different...

I personally don't know anyone unhappy with their Ecodan/Daikin ASHP.

Just my 2p worth

[Air to Water ASHPs discussed here]

I would add that the beauty of the ASHP/PV combination is you forget about it. The house run's itself so to speak for little cash when taking the longer term view...

TiredGeek

TBH I think that the results from the trial can be now ignored by and large. It's simply too old, things have moved on and things have been learnt.

I tend to lean towards the technology, I honestly think it's great, particularly the Mitsi which doesn't need a big indoor unit taking up space.
Given a house in a more ASHP friendly environment and a house which could be better insulated it would be my first choice.

Unfortunately where we are and the type of house is inexorably pushing us towards oil, though I'm thinking a combination of oil and ASHP may well be on the cards.
If we qualify for RHI then it's a no brainer

[Deleted User]

TiredGeek wrote: »

TBH I think that the results from the trial can be now ignored by and large. It's simply too old, things have moved on and things have been learnt.

I tend to lean towards the technology, I honestly think it's great, particularly the Mitsi which doesn't need a big indoor unit taking up space.
Given a house in a more ASHP friendly environment and a house which could be better insulated it would be my first choice.

Unfortunately where we are and the type of house is inexorably pushing us towards oil, though I'm thinking a combination of oil and ASHP may well be on the cards.
If we qualify for RHI then it's a no brainer

Thats's the bit I just do and don't get, insulation & location...

We are in an old house in Scotland with 50% of the house having 3m ceilings and 50% bare floorboards... House nice and warm with low bills??? Loft badly needs more insulation as what was there was wrecked with ASHP/solar/mains smoke alarms installs and other work... Will redo that from scratch shortly. System has fast warm up times too...

I think that is why EST/DECC did not want to monitor us they thought the results would be crap! But then came back to us, probably cos no !!!!!! is installing them due the the RHI farce and poor results in the last trial...

TBH I have no interest in finding out what my COP might be, all that interests me ££ per month on the leccy...

TiredGeek

jeepjunkie wrote: »

We are in an old house in Scotland with 50% of the house having 3m ceilings and 50% bare floorboards... House nice and warm with low bills??? Loft badly needs more insulation as what was there was wrecked with ASHP/solar/mains smoke alarms installs and other work... Will redo that from scratch shortly. System has fast warm up times too...

TBH I have no interest in finding out what my COP might be, all that interests me ££ per month on the leccy...

Whereabouts are you in Scotland? You may have said previously, I can't recall...

Our place is very close to the coldest place in the UK - Altnaharra, regularly get's below -20'c in winter and can stay there for weeks at a time.

Your house sound very similar to ours, same ceiling height, same floor coverings (except we have one stone slab floor as well). No wall insulation possible, but double glazed throughout and very well insulated roof space. Floor area of about 170sqm.

Our particular problem seems to be the micro climate we find ourselves in: bottom of a strath, with a river, near a loch, not far from the sea. In the same strath as Altna. We have recorded temps of -22'c and for two weeks it did not get warmer than -17'c!
We have a home weather station which regularly shows relative humidity in the high 80% region, and we're convinced this causes excessive frosting of the ASHP and subsequent defrosts.

Combine the micro climate with a relatively poorly insulated house and it seems to just lead to poor performance and high running costs in our case

We couldn't care less about the COP either so long as we can afford to heat the place without being plunged into fuel poverty.

Low carbon isn't our priority, in fact, if it was cheap to run and heated the house we'd install a CO2 generator.
We were around in the early 80's when "renowned scientists" were absolutely certain, and had conclusive proof, that we were heading into another ice age very shortly.
Pretty much like the "renowned scientists" today who are absolutely certain, and have conclusive proof, that we have man made global warming due to CO2 emissions

[Deleted User]

TiredGeek wrote: »

Whereabouts are you in Scotland? You may have said previously, I can't recall...

PM sent, cheers

[Deleted User]

TiredGeek wrote: »

Whereabouts are you in Scotland? You may have said previously, I can't recall...

Our place is very close to the coldest place in the UK - Altnaharra, regularly get's below -20'c in winter and can stay there for weeks at a time.

Your house sound very similar to ours, same ceiling height, same floor coverings (except we have one stone slab floor as well). No wall insulation possible, but double glazed throughout and very well insulated roof space. Floor area of about 170sqm.

Our particular problem seems to be the micro climate we find ourselves in: bottom of a strath, with a river, near a loch, not far from the sea. In the same strath as Altna. We have recorded temps of -22'c and for two weeks it did not get warmer than -17'c!
We have a home weather station which regularly shows relative humidity in the high 80% region, and we're convinced this causes excessive frosting of the ASHP and subsequent defrosts.

Combine the micro climate with a relatively poorly insulated house and it seems to just lead to poor performance and high running costs in our case

We couldn't care less about the COP either so long as we can afford to heat the place without being plunged into fuel poverty.

Low carbon isn't our priority, in fact, if it was cheap to run and heated the house we'd install a CO2 generator.
We were around in the early 80's when "renowned scientists" were absolutely certain, and had conclusive proof, that we were heading into another ice age very shortly.
Pretty much like the "renowned scientists" today who are absolutely certain, and have conclusive proof, that we have man made global warming due to CO2 emissions

Have you considered air-to-air ASHPs? They are very efficient and quality units can cope with very low temps. I've seen units running when temps as low as you quote. Just an idea that's hugely cheaper than an air to water system... A DHW solution is still required.

I can't suggest anything specific as I don't you your layout, living habbits etc but could be an option to have a couple or more units running during the bulk of the year to keep [most] the house at a comfortable temp?

An oil boiler could supplement in the worst weather?

Cheers

TiredGeek

jeepjunkie wrote: »

I can't suggest anything specific as I don't you your layout, living habbits etc but could be an option to have a couple or more units running during the bulk of the year to keep [most] the house at a comfortable temp?

An oil boiler could supplement in the worst weather?

Cheers

We're looking into a combined ASHP / oil setup at the moment.
Air to air isn't really viable now as the rads are in, and as we'd need one unit per room the costs would very quickly add up, including hallways that would be 16 units, at least
Plus there's the issue of getting the pipes through the 18" solid granite walls to consider....and the electrics. I'm not sure it would look all that nice either with loads of those things hanging off the walls.

It's got to be a wet radiator system, just don't know which yet