# Air Source Heat Pump - Worth it?



## dj01

I am in the middle of a new build and in the next couple of months will be getting an air to water heat pump installed (air source heat pump). 
I've met people who are using the same system and they have told me that their electrical running cost over a year are at least a 1/3 cheaper (inc. all domestic their electricty costs)  than just heating with oil would be.  

The initial cost of the unit is quite expensive, but I feel that it will recoup the costs over a 5 year period. 

Before fully commiting to the system I would be very interested in hearing from anyone who is currently using an air source pump, and what their opionions on it?

thanks
dj01


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## sydthebeat

The physical performance of the heating system depends greatly on the construction specification and standard of the build. 
For an ATW heat pump id aim for a min B2 achievable insulation standard. I would highly recommend a HRV system and not passive vents, and incorporate windows not greater than 1.2 u values.


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## Birroc

sydthebeat said:


> The physical performance of the heating system depends greatly on the construction specification and standard of the build.
> For an ATW heat pump id aim for a min B2 achievable insulation standard. I would highly recommend a HRV system and not passive vents, and incorporate windows not greater than 1.2 u values.


 
Yeah I am going for a HRV system. Seems more logical than putting holes in my walls !

Syd, can you recommend a good window company ? Nationwide or Galway.


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## sydthebeat

[broken link removed]

have a read of this article....


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## GubMan

SYB,

I've an oil fired boiler but given what its cost me this year so far, I'm looking to possibly put in a ATW system to reduce costs later in 2008.  The house, while relatively new, has passive vents and a lot of glass.  Is an ATW a viable option for me?  and what kind of budget am I looking at?


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## BarneyMc

dj01 said:


> The initial cost of the unit is quite expensive, but I feel that it will recoup the costs over a 5 year period.
> 
> dj01


 
I'm considering an air to water heat pump also (plan to build an ICF house). What manufacturers/models are you looking at and what ones are your friend's using? Are they using UFH or the special "low heating" radiators? Thanks!


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## ItsOnToday

GubMan said:


> SYB,
> 
> I've an oil fired boiler but given what its cost me this year so far, I'm looking to possibly put in a ATW system to reduce costs later in 2008.  The house, while relatively new, has passive vents and a lot of glass.  Is an ATW a viable option for me?  and what kind of budget am I looking at?




How old is your Oil boiler, because I just replaced my old one with a brand new unit, and I must say the newer units use up wayyyyy less oil than used to. I can get it prepped at the end of September and it will last me 'til the end of winter. Plus, if you get your oil early on you can get a cheaper price. Some places are even offering Price Protection.


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## GubMan

2 years old, same as the house, its a firebird.  Problem is the house, while well insulated is 3100 sq ft., so I've gone through exactly 2892 euro of oil since the start of the usual cold snaps last year.  I've just got another 500 euro of oil, 640 ltrs now versus 720 ltrs in January for the same 500 euro.  Oil is becoming a non-runner big time and the wife is not going to stop turning on the heat during the day when she feels it chilly.  So you can see how I want to get another source that can reduce the oil dependance, as i'm sure the price is going only 1 way!


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## dj01

Thanks for all the info. Am going to go with this system, I'm insulating well and feel even with the initial outlay cost, it will pay for itself and more over time. Was speaking to someone recently who mentioned wind turbines for generating your own electricity, something I would be interested in as it becomes more available and the units become more affordable.


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## mahoney.john

dj01 said:


> I am in the middle of a new build and in the next couple of months will be getting an air to water heat pump installed (air source heat pump).
> I've met people who are using the same system and they have told me that their electrical running cost over a year are at least a 1/3 cheaper (inc. all domestic their electricty costs)  than just heating with oil would be.
> 
> The initial cost of the unit is quite expensive, but I feel that it will recoup the costs over a 5 year period.
> 
> Before fully commiting to the system I would be very interested in hearing from anyone who is currently using an air source pump, and what their opionions on it?
> 
> thanks
> dj01


air source pump, which  transfers heat between your house and the outside air are very suitable for either indoor or outdoor installation and provide significant installation cost benefits over ground source systems, as there are no requirements for expensive ground loops to be installed.
*It *can provide 100% of the heating requirement down to air temperatures as low as 0°C, and are easily boosted for the few days of the year when temperatures fall consistently below this level


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## suilagorm

When you say it costs about 1/3 less than oil, is this with night-saver electricity or normal rate electricity?  If you use night rate plus thermal storage system, and mainly run at the night rate, would this increase effeciency? And are you factoring in the extra cost of night rate rental fron electricty supplier?


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## callanrory

I am currently building a house and would love to know all your views for those who have posted earlier threads and have gone ahead with it.  Did yee use UFH or radiators.  Are the savings really what they say they are especially with the ESB bill being incorporated for the running of the compressor.

Thanks.


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## dj01

See thread below on Geothermal costs which may be of interest, i posted my 1st years running cost here as well. We're in our house 15 months and are very happy with how the system has performed. The system runs UFH throughout. Was just thinking how impressed I was with the system on a night like last night where temperatures dropped, the house was very warm with an constant even heat, and the warm floors in my view just can't be beaten.

http://www.askaboutmoney.com/showthread.php?t=34579&page=6


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## moloney2

Have just installed an air source heat pump to run in conjuction with an existing oil burner and existing radiators, the oil burner takes over when the temp. drops below optimum efficiency for the air source heat pump. The house is 1200 sq. feet and there are 11 convection radiators. For approx. 1500 euro we sourced the heat pump in the UK and installed it ourselves with the free assistance of a qualified neighbour. We also installed thermostats, thermo valves on radiators and zoned our system into living, bedrooms and water. Hopefully we should see a big decrease on our fuel bills this year.


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## callanrory

Thanks for that dj01.  Just one final question in relation to this system.  Have u a backup boiler or do you work off immersion when the temperature drops below the capabilities of the air to water system?.  I am being informed that when the temp drops below -3 Deg Cel, the air to water system will require a backup.

I got a recent quotation which includes the air to water pump - installing the underflooring heating on both ground and first floor, hot water system and electrical control system for circa €28k plus VAT.  What are ur thoughts on this or who did install yours.

My house will be 2900ft2 also, so its very good to know the running costs.  Thanks again.


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## dj01

The system we installed doesn't require backup (check manufacturer spec, it will tell you but most of these systems should be able to cope with Irish weather conditions) but as the temperature drops the heatpump does call on the use of a built in auxillary heater (heating element) to help heat the water, which does use more electricity. 

Some people have mentioned putting in an 2nd heat source for use when weather gets very cold, personally I didn't see that being  cost effective, but ultimately that's your choice. The system will work in very cold weather, just not as efficiently as it does when temperatures are warmer.

We didn't install HRU either, so can't really advise whether it would offer additional savings.

The best advise is to insulate as much as possbile, if you can't keep the heat in, no system will be cheap.


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## olddog

I may  have worked on one or two air to air heat pumps over the years (!) but have no significant experience with air to water heat pumps - so I may have the wrong end of the stick with regard to the topic..

1. If your heat pump can deliver a COP of over 3 then the cost per kWhr of heat from it is probably not more than from an oil burner. The real carrot is that running it on night rate electricity will cut the cost per kWhr of heat in half

2. At present air to water heat pumps are most appropriate to underfloor heating systems ( its hard for them to operate with high COP if raising the water temperature to be suitable for radiators )

3. It would seem to me that one of the design aims would be to store enough heat from night time running to see you through the day. I suspect that this translates into careful specification of the floor ( screed etc ) to ensure that there is sufficient thermal mass to store the required energy and also specification of the heat pump so that it can generate sufficient KWhr s of heat during the night rate period to cover all the day. I guess that this means a heat pump with perhaps twice the rating of what might otherwise be required.

In old technology houses this would probably not be practial as the heat required would be just to large however with new technology houses ( the type that can be heated with a toaster ) this should not be such a problem.

Please tell me if I have totally lost the plot



Olddog


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## greenred

Am looking at an air-to-water system myself for a 5,000ft+ house. 

Have more or less decided on this as I feel oil is not an option (oil to get more expensive in time), geothermal will be more expensive as you have to bore holes (the unknown of how many holes will be needed), woodpellets (large bulky system, with questions over the supply & quality of pellets). 

One air-to-water system I have been quoted (with UFH) on includes a back up of an oil boiler & this is coming in at €32k (inc vat). Just wondering if anyone else has a similiar system in a similair size house & are the ESB bills managable? 

I have hear that solar panels are not worth it either as you will never get to recoup your outlay. I would be looking at an outlay of €5k for same, and I beleive hot water per year is between €200 & €300 so it would take almost 17 years for solar panels to pay for themselves.  

dj01; you say your ESB bills for 1 year came in @ less than €1,800 - for a 2,900 sq foot house. I hope that with a high level of insulation that I can acheive same. Or am I not being realistic? 

You may ask why have I built a 5k sq foot house then, good question, I have not - I am completing a partially built house.  

Thanks in advance
Greenred


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## galwaytt

We have a pair of 100m2 semi's with NIBE Fighter 360 air-to-water units.

They do work very well, but I'd have to put the caveat on it that they work well on that size of house - I'm not convinced how good (..the larger units) would be, on a bigger house.

The ESB bill is higher, per 2-month, compared to normal, but, there's no oil, coal, etc etc, and you have to build the house to a high insulation and airtightness standard. There would simply be no point in putting them in a 'standard' house.

The units in question are in 2 1/2 storey houses, UFH ground floor in conc, UFH under wood on the First Floor and Rads on the 2nd floor, and the houses have no chimneys.

I think they fall into the same grey area as Geo - the technology works, but the price of electricity here is a big problem - and even the Night Rate scheme isn't all it seems to be, seeing as they charge you extra just for having it. For a company that wants us to save energy (ESB), and make life for the grid that much easier, by spreading demand into off-peak hours, they're doing a very poor job. I have night rate in my house, and had planned to use it for appliances, washers etc, but the extra cost to get it in, and the extra rental, are cancelled by any savings, imho.  I was on to them to get it removed, and the irony is:  they charge even more to remove it !


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## onq

galwaytt,

I'd be interested to learn just how much higher are the electricity bills you're talking about, particularly during the winter months.
I was talking to a seller of similar systems in Plan Expo 2009 and he was suggesting combining it with a wind turbine and/or solar panels to help pay for the electicity.
The issue, as always is in the depths of winter in Ireland you have cold, cloudy, windless days [a bit like yesterday and today], where neither of those "assists" would generate much power.
Plus the real energy drain is water heating and cooking, serious ergs needed here and your comments seem to center solely on space heating.

In relation to the ESB, they've been plucking the choicest fruit for so long they don't seem to know what competititon is.
With the number of people we have coming to the door offering reductions, [air, gas generation] that may change.

I think chemical power is the great unexploited easily accessed resource for use in temperate climates.
Teams of mice chasing cheese on little treadmills is where its at - pus you'll never be alone again!

ONQ.


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## galwaytt

Onq - I'll dig out the bills, and revert here.

Sorry, the NIBE also provides all the DHW too, no other heat sources in the house.

Well, apart from the Dimplex 'effect' fire in the sitting room, which is used in 'light effect' mode, to save staring at a blank wall.   Got penalised in the BER just for bringing it in the door, mind...................uPVC std double glaze windows, no renewable energy (solar etc) at all, and a B1 rating.

That, and the NIBE unit wasn't on HARP at the time of the Cert, so got hammered for that at the time too, as they wouldn't give the efficiency rating that NIBE were quoting, either.   5 pts short of A3, iirc...(2+ years ago now....)

I'll be back a.s.a.p.


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## onq

galwaytt said:


> Onq - I'll dig out the bills, and revert here.
> 
> <snip>



Ta muchly. Just completed an A3 rated house. Has heat exchanger and a whole load of Rockwool insulation in a dormer bungalow style 5-bed dwelling.

ONQ.


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