Best air to water heat pump

JD6910 · 25-01-2013 9:50am #1

hi all,

any suggestions on the best air to water heat pump to install in a 3000sq ft house???

lollymob · 04-02-2013 12:39pm

Hi JD6901,
Just wondering did you get any reply's by PM. Im also building a 3000 sq foot house and provisional BER has stated that we must use either geothermal or air source heat pump. We're considering air source and looking for reputable companies that supply these systems. I'm based in the midlands. Have you had any luck yet?
Lollymob

JD6910 · 08-02-2013 2:33pm

nobody replied!!!!!

correct me if im wrong - if you are to comply with part L and put in the amount of solar needed along with oil and rads - it works out the same as the air to water??????

if this is the case - i would suggest the air to water is the way to go????????????????

blast06 · 09-02-2013 9:22pm

In the midlands as well.
Decided yesterday to go with the air to water heat pump. Will have the usual air tight membrane, HRV (although haven't a clue what spec to go for there), 400mm wool in attic plus sheets of Polyiso and also Quin lite inner leaf with 6" pumped cavity. .... have UFH heating downstairs (with no less than 140 mm of insulation under the screed (2 x 70mm) and 85mm of screed (not going with easy screed as house will be occupied 9-5) plus rads upstairs (although upstairs just 1/3 size of downstairs)..... all in all an A3 rating

My problem with a large mix of options from BER prelim report was that i would have needed 6 m2 of solar panels so going for that option plus highly efficient oil burner would have cost ~8K. The air to water heat pump (11 Kw) cost ~10K.
I started dealing with 3 companies and settled for 1 even though full package (UFH plus heat pump plus tank) with them was €500 dearer than 2nd choice.

My only reference point was a neighbour who got it a couple of years ago and is thrilled with it. PM for details of who i went with !!

lainatro · 21-02-2013 3:05pm

same here, nearly starting in 3 weeks. Not decided but it seems that if house is 3000 sq ft, solar is just not an option. They wont allow it really...

So stupid. In my opinion, at the end of the day, solar is free energy. electricity is not free...

It's just that I am willing to insulate and ventilate, by doing so, burning oil as back up is very efficient in the extreme cold.

A low heat flow system is just bothering me... yet the goverment do not care about our pockets, just their pockets...

Can any of you PM me some details as I need o look at my options

lollymob · 21-02-2013 4:02pm

Hi Iainatro,
I'm in the same position as yourself and ready to start build very soon. I have been getting quotes for both air source and geothermal with underfloor for the past few weeks. I'm finding it very hard to compare quotes and make a decision. Some companies who sell both air and geo advised me to go with air, others recommended geothermal. One company quoted me 18,995 for 14KW air to water with underfloor another quoted me 19,618.47 for 16KW air to water with underfloor. House is 3169 sq foot. Any experts out there know would the 14KW be sufficient to heat this size of house? I got other quotes but I'm waiting for installers to get back to me with a price so I can compare all quotes accurately. Feel free to PM me for details of companies I got quotes from. If anyone has any recommendations to make I would strongly welcome them.
Thanks,
lollymob

blast06 · 22-02-2013 12:02am

Am veering towards the geothermal (borehole option) lollymob after all !
The price of drilling a 200m hole is a bit less than i thought (i'd say i would get it for close to 3K!.... same guy charged 5.5K for a work colleague for hole of same depth about 4 years ago). If you decide to go down that path (i can't recall what you said yo are doing there) then PM me ..... a quote for 2 jobs might give us another few bob off !! ... or better still for 3 lainatro if you are interested !!

lollymob · 22-02-2013 12:57am

blast06 wrote: »

Am veering towards the geothermal (borehole option) lollymob after all !
The price of drilling a 200m hole is a bit less than i thought (i'd say i would get it for close to 3K!.... same guy charged 5.5K for a work colleague for hole of same depth about 4 years ago). If you decide to go down that path (i can't recall what you said yo are doing there) then PM me ..... a quote for 2 jobs might give us another few bob off !! ... or better still for 3 lainatro if you are interested !!

Fair play to you blast06, I've changed my mind about 10 times and still can't decide!! I'd say our soil will be suitable for geothermal I just don't know about spending that extra 2 or 3 k! Pm me the company you went with if you don't mind!
Cheers, lollymob

Tommyboy08 · 22-02-2013 7:29pm

blast06 wrote: »

Am veering towards the geothermal (borehole option) lollymob after all !
The price of drilling a 200m hole is a bit less than i thought (i'd say i would get it for close to 3K!.... same guy charged 5.5K for a work colleague for hole of same depth about 4 years ago). If you decide to go down that path (i can't recall what you said yo are doing there) then PM me ..... a quote for 2 jobs might give us another few bob off !! ... or better still for 3 lainatro if you are interested !!

Make sure he doesn't drill one 200mtr bore
Insist on 2 100mtr bores and make sure that he grouts the holes too, I've seen too many problems with bad boreholes too deep is a prob and not back filled with grout is even worse,
If the price seems very cheap then he's probably taking shortcuts,
And pea gravel is not a suitable material for the job!!!!!!!

blast06 · 22-02-2013 9:08pm

Thanks Tommy.
I'm only beginning to look at the borehole aspect and certainly the 2 x 100m versus 1 x 200m was a question i had .... particularly when the guy said he recently drilled 2 x 100m holes for this sister for geothermal and said "well easier on me (half a laugh) - not much difference anyway".
I'm only at the beginning of all this anyway so have a good bit to learn.

fclauson · 25-02-2013 7:26pm

lollymob wrote: »

Hi Iainatro,
I'm in the same position as yourself and ready to start build very soon. I have been getting quotes for both air source and geothermal with underfloor for the past few weeks. I'm finding it very hard to compare quotes and make a decision. Some companies who sell both air and geo advised me to go with air, others recommended geothermal. One company quoted me 18,995 for 14KW air to water with underfloor another quoted me 19,618.47 for 16KW air to water with underfloor. House is 3169 sq foot. Any experts out there know would the 14KW be sufficient to heat this size of house? I got other quotes but I'm waiting for installers to get back to me with a price so I can compare all quotes accurately. Feel free to PM me for details of companies I got quotes from. If anyone has any recommendations to make I would strongly welcome them.
Thanks,
lollymob

What is your building heat deamnd - my house is larger but only had a 9Kw HP (of which 6 is the immersion which is permantly switched off !!!!)
14 or 16 sounds way to much for a well insulated building

Do a PHPP calc

rockabaloo · 25-02-2013 9:26pm

fclauson wrote: »

What is your building heat deamnd - my house is larger but only had a 9Kw HP (of which 6 is the immersion which is permantly switched off !!!!)
14 or 16 sounds way to much for a well insulated building

Do a PHPP calc

Is that the way the heat pump works?

Looking at the Mitsubishi Ecodan 8.5 kW for example at A2/W35 the power input is 2.68 kW with a COP of 3.17 to get a 8.5 kW output.

So the 8.5 kW heat pump is the the maximum output of the pump. Is this not the case?

Condenser · 25-02-2013 9:29pm

rockabaloo wrote: »

Is that the way the heat pump works?

Looking at the Mitsubishi Ecodan 8.5 kW for example at A2/W35 the power input is 2.68 kW with a COP of 3.17 to get a 8.5 kW output.

So the 8.5 kW heat pump is the the maximum output of the pump. Is this not the case?

Air to water units need to oversized by at least 30% to account for their drop in efficiency, and hence output, when temps are low.

rockabaloo · 25-02-2013 10:16pm

Do they not just use more power when COP drops e.g., the 8.5 kW unit would use 4.25 kW at COP of 2 which means the 8.5 kW output is maintained rather than needing to oversize the unit?

Condenser · 25-02-2013 10:23pm

rockabaloo wrote: »

Do they not just use more power when COP drops e.g., the 8.5 kW unit would use 4.25 kW at COP of 2 which means the 8.5 kW output is maintained rather than needing to oversize the unit?

No they lose output as they can't collect as much energy. The power consumption will go up slightly as the work that needs to be done to raise the temp of the gas is greater. It basicly means much more running hrs and not being able to meet heat demand below a certain temp hence the need to oversize.

rockabaloo · 25-02-2013 10:27pm

I see. Good info. Thanks.

lollymob · 25-02-2013 10:59pm

fclauson wrote: »

What is your building heat deamnd - my house is larger but only had a 9Kw HP (of which 6 is the immersion which is permantly switched off !!!!)
14 or 16 sounds way to much for a well insulated building

Do a PHPP calc

Thanks fclauson,
To be honest I don't know what my building heat demand is... Is this on my provisional BER? Where or who would you get a PHPP done with? Please excuse my ignorance, I'm trying to educate myself as I go!!

corollap · 10-05-2013 1:03pm

Just wondering how your are getting on with your air to water heat pump. I am thinking of installing one. What are the running costs like? And what temperature do you run it at? sorry about all the questions!!

Curious Geroge · 02-06-2013 8:43pm

corollap wrote: »

Just wondering how your are getting on with your air to water heat pump. I am thinking of installing one. What are the running costs like? And what temperature do you run it at? sorry about all the questions!!

+1 on this information. I've changed my mind too many times over the past couple of months and its getting close to decision making time..

sgc86 · 01-04-2016 5:28pm

Hi

just wondering did you go for the air to water pump in the end?? If so do you have an average bill amount? just trying to budget - we have bought a new build that comes with this system as well as solar panels
Any info would be helpful Thanks

fclauson · 02-04-2016 8:05am

sgc86 wrote: »

Hi

just wondering did you go for the air to water pump in the end?? If so do you have an average bill amount? just trying to budget - we have bought a new build that comes with this system as well as solar panels
Any info would be helpful Thanks

average bill is nonsense as it demand driven

primary energy @ a mix of 18c/unit day rate and 9c/unit night rate
lets call that 13 as an average as more is at night than in the day

I have just read the meter for 2015
my heating bill is low but that is because my house is Passive

484 hrs of heat pump time at 2.2Kwh/hour = 968 Kwh = €125 per annum

a better guide is that my hot water is around €250 (4 people - 3 of which are of the fairer sex, 2 of which are teenagers !) -
900hrs of heat pumpt time at approx 2.2kwh/hour running time =1980Kwh
€257 hot water bill for the year approx

sgc86 · 02-04-2016 11:39pm

ðŸ™ˆ Sorry, by average I just meant if u had a total divided by 12months.
ðŸ‘ Sounds great... hopefully ours will be good with only 2of us in the house!
Thanks for the feedback! ☺

fclauson wrote: »

average bill is nonsense as it demand driven

primary energy @ a mix of 18c/unit day rate and 9c/unit night rate
lets call that 13 as an average as more is at night than in the day

I have just read the meter for 2015
my heating bill is low but that is because my house is Passive
484 hrs of heat pump time at 2.2Kwh/hour = 968 Kwh = €125 per annum

a better guide is that my hot water is around €250 (4 people - 3 of which are of the fairer sex, 2 of which are teenagers !) -
900hrs of heat pumpt time at approx 2.2kwh/hour running time =1980Kwh
€257 hot water bill for the year approx

Mack05 · 25-01-2018 5:49pm

Hi all,
Thinking of changing my oil and turf combo heating to a Air to Water heat pump, have underfloor on both floors and two rads in the converted attic on the third floor, house is about 3000square metres. I’m in the midlands. If anyone would know a good company to go with and some prices I would very much appreciate any info, Thanks.

Ray Donovan · 25-01-2018 8:16pm

Mack05 wrote: »

Hi all,
Thinking of changing my oil and turf combo heating to a Air to Water heat pump, have underfloor on both floors and two rads in the converted attic on the third floor, house is about 3000square metres. I’m in the midlands. If anyone would know a good company to go with and some prices I would very much appreciate any info, Thanks.

When was your house built?

Retrofitting a house with an A2W if the house is not highly insulated is a BAAAAAD idea!!

Mack05 · 26-01-2018 2:57am

Ray Donovan wrote: »

When was your house built?

Retrofitting a house with an A2W if the house is not highly insulated is a BAAAAAD idea!!

Thanks Ray,

Built the house in 2006, it’s pretty well insulated, the inside of all the external walls are insulated with ‘I think the size is’ 38mm insulated plasterboard, the attic is also well insulated. Have a E-con boiler for burning turf when lit for one day the house will be warm for 2 to 3 days after, it’s just the hassle of turf and we’re both working now so not there during the day to keep a fire going plus I found the oil expensive before I got the E-con boiler. Just looking for a better option to heat the house. Would ya have any info or prices regarding A2W or Geothermal?
Thanks again.

ChrisR1818 · 31-01-2018 10:46am

Mack05 wrote: »

Hi all,
Thinking of changing my oil and turf combo heating to a Air to Water heat pump, have underfloor on both floors and two rads in the converted attic on the third floor, house is about 3000square metres. I’m in the midlands. If anyone would know a good company to go with and some prices I would very much appreciate any info, Thanks.

Not sure if you've heard of Sola Energy Solutions but they seem to have a fairly good set up. The price would depend on the size of the heat pump really.

Mack05 · 31-01-2018 11:22am

ChrisR1818 wrote: »

Not sure if you've heard of Sola Energy Solutions but they seem to have a fairly good set up. The price would depend on the size of the heat pump really.

Thanks Chris I’ll check them out.

Howlin · 02-02-2018 11:11pm

Mack05 wrote: »

.....have underfloor on both floors and two rads in the converted attic on the third floor, ....

Just be mindful that a Heat Pump wouldn't be able to bring the temperature of the rad up to what it was at with the oil/turf heating. Normally, Air Sourced Heat Pumps gets water up to 35ish.

This just means, the rads wouldn't get hot enough to supply the required heat output to potentially heat the room. There are specific rads that can operate with a heat pump but they are normally longer rads.

From the people I work with and know who have geothermal, they wouldn't be rushing out to sing their praise, this is mostly because they are finding it very difficult to find people who are capable to service them. There are a lot more air to water heat pumps, so getting them services would be easy.

Mack05 · 03-02-2018 1:05pm

Howlin wrote: »

Just be mindful that a Heat Pump wouldn't be able to bring the temperature of the rad up to what it was at with the oil/turf heating. Normally, Air Sourced Heat Pumps heat output to potentially heat the room. There are specific rads that can operate with a heat pump but they are normally longer rads.

Thanks for that Howlin, didn’t know it wouldn’t give full hot water supply. Probably need Solor Panels as well for the water?
I wouldn’t be worried about the Rads on the third floor reaching full heat as they are turned down to almost off because it’s well insulated and the rooms gets to hot up there.
Thanks for the advice and if you’ve anymore info on the Air to Water systems that would be great,
Thanks again ðŸ‘

fclauson · 03-02-2018 1:17pm

Howlin wrote: »

...very difficult to find people who are capable to service them. ...

The great thing about a heat pump is there is no servicing !!

Yes - a couple of filters to clean - and check the pressure release value - and top up the water pressure as required

KCross · 03-02-2018 1:32pm

Howlin wrote: »

From the people I work with and know who have geothermal, they wouldn't be rushing out to sing their praise, this is mostly because they are finding it very difficult to find people who are capable to service them.

I'd sign their praises, if I could sing!

Several respectable service companies around Cork/Munster region so servicing isn't an issue, not that they need much servicing anyway.

Howlin wrote: »

There are a lot more air to water heat pumps, so getting them services would be easy.

When deciding between A2W and Geo(or any heating system for that matter) you should take more into account than servicing.

1) Capital cost
2) Running cost
3) Maintenance cost
4) Most importantly.... expected lifespan.

Try to put all those numbers together and then decide which one makes most sense.

Best air to water heat pump

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