Air-source heat pumps or Geo thermal

Max Power2

I'm planning on building an approx 3000 sqft house and working out what's the best combination of renewable energy - I'd been planning on geothermal heat pump and a wind turbine - but I've been hearing about air-source heat pumps being cheaper and less trouble.
any views?

abakan

Ive been looking into the same options.

We looking at the Air source heat pump -Onscher model.

The Geothermal seem to much money to spend and alot of ground work and then to find out it dosent work aswell as it should.
Thats not saying the Air Source wont be the same but we're lookin into it.

If you do a search on Google in Ireland, you will get mostly website that promote the Air Source heat pump and not people's experiences.......whats thay saying?

ferngreen

Basically the COP of the air to water is lower than the geothermal (in most cases)

The advantages of the Air to water is the obvious lack of civil works (no digging up the garden)
Also its no issues if you need to extend and easier access for maintanance

m_stan

Is there anyone here that has installed an air-source system and can speak to it's performance? Lots of comments on this forum from suppliers and other commentators but would love to hear from someone independent who's actually installed it and can talk about how it's working.

Many thanks

rebellad

m_stan wrote: »

Is there anyone here that has installed an air-source system and can speak to it's performance? Lots of comments on this forum from suppliers and other commentators but would love to hear from someone independent who's actually installed it and can talk about how it's working.

Many thanks

Have posted this in the Heat Pump Performance Section as well so if the mods feel this is duplication can they please delete it.

It has performed quite well over the recent cold spell, I had one issue with the drip tray freezing alright and I must get onto the supplier about it. House was warm for most of the cold spell except for the time the drip tray froze which prevented the fan from working. It took a while to get the heat back up but I think this was more to do with the ufh rather than the air to water unit. (We were away at the time so didn't notice until we came home two days later). With regards to the esb costs, I have been taking a reading from the esb meter every monday for the last month and these are the average daily costs :

21st Dec - 28 Dec €5.80
28 Dec - 4th Jan €6.37
4th-11th Jan €6.83
11-18th Jan €6

These costs include the standing charge + vat etc and are for all electricity consumption in the house.

The one thing I would say is it is like any heating systems really in the fact that as much as the installer can recommend settings for you it takes a bit of tweaking to get it right. We had some days where it was a bit chilly and other days where it was extremely warm, but hopefully when the next cold spell comes along the settings should now be ok!!!

Eurorunner

Hi rebellad.
Can you confirm size of house, level of insulation and the make, model & output of the unit your using?
Are you using this unit exclusively for heating the house or is it a primary or secondary heating source?

yop

rebellad wrote: »

Have posted this in the Heat Pump Performance Section as well so if the mods feel this is duplication can they please delete it.

It has performed quite well over the recent cold spell, I had one issue with the drip tray freezing alright and I must get onto the supplier about it. House was warm for most of the cold spell except for the time the drip tray froze which prevented the fan from working. It took a while to get the heat back up but I think this was more to do with the ufh rather than the air to water unit. (We were away at the time so didn't notice until we came home two days later). With regards to the esb costs, I have been taking a reading from the esb meter every monday for the last month and these are the average daily costs :

21st Dec - 28 Dec €5.80
28 Dec - 4th Jan €6.37
4th-11th Jan €6.83
11-18th Jan €6

These costs include the standing charge + vat etc and are for all electricity consumption in the house.

The one thing I would say is it is like any heating systems really in the fact that as much as the installer can recommend settings for you it takes a bit of tweaking to get it right. We had some days where it was a bit chilly and other days where it was extremely warm, but hopefully when the next cold spell comes along the settings should now be ok!!!

Thanks for putting up them figures there poster. Out of interest whats your electric bill for the year?
Avg that out at 6 euro for them 4 days and multiply by 365! Thats 2190 or even a fiver per day thats 1825, thats pricey enough.

Would be interested to know alright about the house structure and insulation levels.

Lightning McQue

Folks

It most be very cold in Mayo that the heating has to be on for 365 days of the year!!!!

How about 6 months

ESB Bill say €1100

That seems ok depending on size of the house.

Lightning

rebellad

yop wrote: »

Thanks for putting up them figures there poster. Out of interest whats your electric bill for the year?
Avg that out at 6 euro for them 4 days and multiply by 365! Thats 2190 or even a fiver per day thats 1825, thats pricey enough.

Would be interested to know alright about the house structure and insulation levels.

Sorry don't have a full year yet as only in the house since the start of July but total for electrticity paid so far up to the start of this week is €600. Up to the start of November it was averaging around €2 a day but that was when we started putting the heating on more often and lights etc being used more so that was when the daily average started going up. I guess if I have to pay the same again for the next 6 months the yearly total will be €1200 which would be good, even though I hope it will be less as the spring/summer kicks in. THe house is 2700 sq ft story and a half with 100mm insulation in the cavities, drylined walls, 100 mm insulation in ground floor, 30mm upstairs floor and 200mm in roof. Unit is being used exclusively for all heating and DHW, I heat the water over night using the cheaper night rate electiricty and there is plenty of water there for myself and the better half for washing, showering etc the next day. It is the Daikin Altherma system

yop

rebellad wrote: »

Sorry don't have a full year yet as only in the house since the start of July but total for electrticity paid so far up to the start of this week is €600. Up to the start of November it was averaging around €2 a day but that was when we started putting the heating on more often and lights etc being used more so that was when the daily average started going up. I guess if I have to pay the same again for the next 6 months the yearly total will be €1200 which would be good, even though I hope it will be less as the spring/summer kicks in. THe house is 2700 sq ft story and a half with 100mm insulation in the cavities, drylined walls, 100 mm insulation in ground floor, 30mm upstairs floor and 200mm in roof. Unit is being used exclusively for all heating and DHW, I heat the water over night using the cheaper night rate electiricty and there is plenty of water there for myself and the better half for washing, showering etc the next day. It is the Daikin Altherma system

That would be very similar amount per year as ourselves. Thanks for the info.

m_stan

Great info - thanks @rebellad.

These costs tally almost exactly with what a supplier of this system was telling me. He also stated that a conventional gas boiler heating system would cost approx 1,800 eur per year to run. He hasn't given me a quote yet but said that the supply and installation of this system including underfloor heating in a 2,500 sq ft two story house could be up to 25k. Given that a gas boiler radiator system would be no more than 10k, thats a difference of 15k. If the annual running costs are only 700 less, you're talking about over 20 years before it pays for the difference.

Can anyone agree or disagree with my figures above?

yop

Not sure what others have installed but we installed ours back in 05/06 in a 2100 sq ft house.
Cost 8500 for the GSHP, 300 for the sand and machine work and it cost me 4500 for the UFH, self installed

gizmo555

m_stan wrote: »

These costs tally almost exactly with what a supplier of this system was telling me. He also stated that a conventional gas boiler heating system would cost approx 1,800 eur per year to run.

....

Can anyone agree or disagree with my figures above?

€1,800 a year for gas heating sounds massive in a well-insulated 2,500 sq ft house. I would seriously question how he arrived at this figure and what assumptions he has made about, for example, how long the heat will be on each day, what temperature you will be heating the house to, etc.

It's easy to show big savings against oil or gas if these assumptions are out of whack with reality.

m_stan

gizmo555 wrote: »

€1,800 a year for gas heating sounds massive in a well-insulated 2,500 sq ft house. I would seriously question how he arrived at this figure and what assumptions he has made about, for example, how long the heat will be on each day, what temperature you will be heating the house to, etc.

It's easy to show big savings against oil or gas if these assumptions are out of whack with reality.

Yes I agree, and even if this is correct a 20 year payback on such a system doesn't sound to attractive to me. So why do it? I know I'm assuming static electricity and gas prices for the next 20 years, but it's difficult to predict how prices will change.

So people, why do it? Can't see it adding up...

rebellad

m_stan wrote: »

Great info - thanks @rebellad.

These costs tally almost exactly with what a supplier of this system was telling me. He also stated that a conventional gas boiler heating system would cost approx 1,800 eur per year to run. He hasn't given me a quote yet but said that the supply and installation of this system including underfloor heating in a 2,500 sq ft two story house could be up to 25k. Given that a gas boiler radiator system would be no more than 10k, thats a difference of 15k. If the annual running costs are only 700 less, you're talking about over 20 years before it pays for the difference.

Can anyone agree or disagree with my figures above?

Installation quote sounds a bit high to me, the total install cost for our heating system were 20.5 k, we got a grant of 2k to bring it to 18.5k. This included UFH upstairs and down, the heat pump, a 300 litre tank and we also got the tank fitted for solar so if we ever decided to get solar it would be just a case of hooking it up to the tank. As far as I remember the heat pump was approx 8k, the tank was 2k, solar connection approx 1k and the rest was for the ufh. This price was agreed in May 2008 so I would have thought the cost would have come down since then....

rebellad

m_stan wrote: »

Great info - thanks @rebellad.

These costs tally almost exactly with what a supplier of this system was telling me. He also stated that a conventional gas boiler heating system would cost approx 1,800 eur per year to run. He hasn't given me a quote yet but said that the supply and installation of this system including underfloor heating in a 2,500 sq ft two story house could be up to 25k. Given that a gas boiler radiator system would be no more than 10k, thats a difference of 15k. If the annual running costs are only 700 less, you're talking about over 20 years before it pays for the difference.

Can anyone agree or disagree with my figures above?

Just on this, I'm saying that for €1200 I would hope to have all my electricity bills covered - this is not just the heat pump. I don't know what the average yearly Electricity cost is without a heat pump but say it was €600 then all my water and heating is costing me €600 for the year

m_stan

thanks @rebellad. Would you mind PM'ing me the name of the company you used? I think posting it here may be forbidden. Appreciate all the info you've provided.

OllieMc

Hi Guys,

Got what I think is a very good quote for the Daikin Altherma with underfloor upstairs and down, stats in all rooms and a MHRV for a 3200 Sq Ft house.

It all comes to 21,000.

m_stan

OllieMc wrote: »

Hi Guys,

Got what I think is a very good quote for the Daikin Altherma with underfloor upstairs and down, stats in all rooms and a MHRV for a 3200 Sq Ft house.

It all comes to 21,000.

Sounds great. Would you mind PM'ing me the company name? Don't think you are allowed post it here. Cheers

Lightning McQue

Hi OllieMc

Can you pm those details

Can you be more exact as to what the quote includes for?

Thanks

Lightning

OllieMc

Hi,

The quotes is for a Daikin Altherma 16kw heat pump, Daikin Hydro Box, with back up heater, Digital thermostats, 303sq/m of underfloor heating. All installed. This came to €18,160.

For €21,000 he said he'd put in the MHRV. I dont know much about this as we never had it planned. All I know is its a Vent Axia Kenetic Plus Sysytem.

I havent fully decided if this is the way we are going but I think at this price we will. I was quoted €27000 for the same setup with a different company.

Ill PM you the details

metalworker65

yop wrote: »

Thanks for putting up them figures there poster. Out of interest whats your electric bill for the year?
Avg that out at 6 euro for them 4 days and multiply by 365! Thats 2190 or even a fiver per day thats 1825, thats pricey enough.

Would be interested to know alright about the house structure and insulation levels.

Yop you are off your head multiplying dec heat requirments by 365. Heat/ hot water energy requirements vary by factor of 10 between summer and winter in irish climate .Ochner 15kw heat pump with boreholes cost me €740 for year , €140 month dec and €12 jul (hot water only demand)

homewardbound11

Hi,
I am looking closely at the Daikin Altherma 16kw heat pump, Daikin Hydro box. The only difference is i plan to use alu rads. The house is well abov regulations with mhrv also in a timberframe house.

I plan to use an air to water system but infrequently. Unfortunately i would say for the most part of the year it will be only water heating only and legionella. but the rest will be cyclical on demand.

Has anyone used alu rads only in a build with air to water. The house is a 3000 sq ft house with provisionall A2 Ber ratings.

I would appreciate commments on the diakin and also with use on alu rads.

Kind Regards,

Wolfhound14

rebellad wrote: »

Sorry don't have a full year yet as only in the house since the start of July but total for electrticity paid so far up to the start of this week is €600. Up to the start of November it was averaging around €2 a day but that was when we started putting the heating on more often and lights etc being used more so that was when the daily average started going up. I guess if I have to pay the same again for the next 6 months the yearly total will be €1200 which would be good, even though I hope it will be less as the spring/summer kicks in. THe house is 2700 sq ft story and a half with 100mm insulation in the cavities, drylined walls, 100 mm insulation in ground floor, 30mm upstairs floor and 200mm in roof. Unit is being used exclusively for all heating and DHW, I heat the water over night using the cheaper night rate electiricty and there is plenty of water there for myself and the better half for washing, showering etc the next day. It is the Daikin Altherma system

Hi Rebellad, I am currently looking into Air Souce Heatpumps and I am interested in what you say about running it on Nightsaver. I understand the logic for a GSHP, but I am having a problem with this setup for Air-to-Water. I understand that the Heatpump uses electricity and it is cheaper to run at night, but surely the efficiency of the Heatpump is much better during the day when the ambient temp is higher? I assume somebody has looked at the Cost-Benefit of this and would welcome any input. Thanks

beyondpassive

I dont share peoples faith in technology, says I from my nice new mac. Would it not be far more prudent to put the capital cost of the eco-bling heat pump into good design, cold bridge reduction, airtighness heat recovery and insulation. I don't see the point of having a big hi tech system, to simply compensate for heat that's being wasted due to bad decisions and workmanship at the build phase?

I've run scenarios for house specifications through passive modelling software and cannot see the justification for such systems.

Even if it cost 20k to go nearer passive with a build, lets call that 10% of the build cost. Your space heat and hot water demand might be 45kWh/m2/an by PHPP standards, so a 200sq house uses 9000kWh at 11kwh per litre which is 820 litres of oil, a thousand litres would cost €665 28 Sec Kerosene Home Heating Oil standard delivery including VAT.

So can someone tell me why with electricity tracking oil and service and parts needed for the heat pump, whose efficiency drops over its lifespan and in cold weather, it is a sounder investment than insulation?

homewardbound11

I share your sentiments and am building a house that would comply with 50 kw/m2/yr demand A2 Rating. I have heat recovery ventialtion and some elemental u values of walls and celing and indeed windows are near or below passive requirements. I did not forsee passive as a goal but am caught by those silly guidlines called PART L.
So with that I have to employ renewables that in your own words cost a fortune and on capital investment (oil/solar to meet 10kw/m2 requirement) it simply means that air to water and expensive geothermal options do make it just as cost effective as oil and solar. Again thanks to the department of environment.
And yes your point still holds. If I had gone a little further I could have done away with both but 3 years ago passive builds were for the minority and seemed to be out of reach for the self builder let alone the architect and engineer locally and my researches at the time did not extend to this.

Basically I need damm all oil to run the building but have to install upto 7m2 of solar aperature area to comply with PARTL.
I think the bold text has shown where my grievence.
For what its worth going the little extra is expensive and hopefully it will pay back itself in the next 20 years. When I initially thought airtight. I didn't forsee the expence in the material, labour, and secondary ancillary items (HRV,room sealed stoves, sealed attic hatches). Not to forget when your first fixes come on board and undo your already sealed house.

Rant over so good night to all.