Air to Air Heat Pumps

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goosebump

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I've seen a lot of info about Air to Water Heat Pumps recently, and new SEAI grants (€3,500) are becoming available for these in a couple of months.

However, there is also going to be a grant for Air to Air heat pumps (€600).

These are basically inverted fridges. They try to cool down the air outside (like a fridge) and the heat generated is transferred inside. If you've ever been on a package holiday to Spain, the A/C unit on the wall of your apartment is one of these. They can do both cooling and heating. Apparently, they are ideally suited to Irish climate for heating, because air is moist and temperatures never fall too far below zero.

The COP score is between 3-5 depending on size of unit, which means for every 1 unit of energy you put in, you get between 3-5 units of heat energy out.

I am thinking of getting one of these for an extension that I have. There doesn't appear to be too many suppliers to residential customers. These guy seems to know what he talking about:

http://heatpumps.scanhome.ie/

Has anyone any experience of these that they could share?
 
I know a friend who has air to water system and electric bill is massive 300e a month. System cost close to 20k to install also. It' a big house but that is crazy money for a new house
 
Can anyone recommend a good reliable heat pump. Any comments about Vitocal Heat pump by Weissman. Are they any good?
 
For the pump to be totally efficient it's advisable to get your house or desired project technically assessed. In short, its air tightness, insulation, draughts, windows, chimneys (if any) etc. When people say it's costing them a fortune in electricity to run the heat pump I can assure you they didn't properly do their homework before going ahead with the work. Goosebump; This is a quickish answer to your query but very relevant.
 
Thanks Coldwarrier & noproblem for your advice. Good to know that their boilers are great. My house has been assessed and what is recommended is a 5k Vitocal by Weismann for my house. Its a semi D with 4, bedrooms
 
Anniekate said:
Thanks Coldwarrier & noproblem for your advice. Good to know that their boilers are great. My house has been assessed and what is recommended is a 5k Vitocal by Weismann for my house. Its a semi D with 4, bedrooms
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Out of interest what does an assessment like this look like and who/where do you get one done? Is it an actual test (ie. seal the doors, pump in air and see how quickly it escapes) or more like the BER?
 
I had assessment done with a retrofit company to measure heat loss when a full insulation job is done e.g attic insulation, floor insulation external insulation ( in my case). A BER would then be achieved and the idea in order to achieve a BER rating to B2 at least for houses built before 2011.
 
Anniekate said:
I had assessment done with a retrofit company to measure heat loss when a full insulation job is done e.g attic insulation, floor insulation external insulation ( in my case). A BER would then be achieved and the idea in order to achieve a BER rating to B2 at least for houses built before 2011.
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o_O
So no air tightness test?
 
@Anniekate
From my understanding, unless your home is air tight, the air to heat pump wouldn't be recommended as a means to heat the home. Maybe as part of the retrofit you are doing, they will be performing this air-tightness? It's difficult to do in existing houses, but I guess not impossible.

The installation of all that insulation needs to be coupled with allowing enough ventilation flow in through the house and out again, so there will need to be a mechanical ventilation system running too.

All this costs money, so depending on your budget, it may / may not be feasible to implement everything. I recently saw on a RTE program (think it was EcoEye?) of a deep retrofit performed on a home, where the costings came to ~ €75K in total, then the applicable grants brought it down to around €50K. The owner did not go through in detail what was done, but at a high level, was the external insulation, new windows, doors, attic insulation and the air-to-heat system. Brought the house to an A rating (A2 or A3 I think).

(The air to water heat system I have in my own home is a Daikin system, double fan - think you were asking about the types in a different thread)
 
Anniekate said:
Not yet
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OK thanks. I'm in a similar position to you, I'd love to move to a heat pump but only if it makes sense to do so. In the case of my home it would fare relatively well on a BER assessment (Xmm of insulation in the walls, Y insulation in the floors). The problem is when I started to do some DIY renovations I found areas where the insulation was missing in the walls, where the plasterboard had a gap of up to 100mm to the floor which was covered with the skirting board, gaps in the concrete floor covered by wooden floor etc etc.

With the quality of much building in Ireland, I think an air tightness test (not assessment) is essential before considering a heatpump.
 
As far as I understand it and in a common sense way, it is at the end, when all work has been completed that the air tightness test is carried out. In order to satisfy the grant criteria, etc and get the rating to the A standard it must meet the standard as set out. It's strict and is done properly. By the way, anyone thinking they can get a survey carried out for free, you can't. However, if you deal with the company that carries out the assessment for you the cost will be allowed off the final price.
On another note and nothing to do with any of the above, as regards getting estimates for any building work etc, is a common enough thing to get from handymen, builders, etc, and doesn't cost anything. But, if you want a detailed quotation for work then most qualified builders and tradespeople are beginning to charge for them because they are now getting Quantity Surveyors to price the work and (naturally enough) passing on the cost. You'll certainly see it if you ask a builder to quote a price for building a house or similar. It gets rid of the "tyre kickers" as they say.
 
noproblem said:
As far as I understand it and in a common sense way, it is at the end, when all work has been completed that the air tightness test is carried out.
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If you were doing a big renovation that would make sense. In my scenario I’m wondering about adding the heat pump to a house that is already at a decent BER but without doing other renovation work, so the air tightness test would be to validate what is already in-place and make sure it is suitable for a heat pump install.
 
noproblem said:
As far as I understand it and in a common sense way, it is at the end, when all work has been completed that the air tightness test is carried out.
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This is flawed logic in the sense that in order to know what / where to address from an air tightness pov, an initial test is paramount imo. Yes, by all means have a second one at the end for input into the BER assessment but it is generally too late then if unknown leaks are doscovered when all finished etc are in place.
 
Micks'r said:
This is flawed logic in the sense that in order to know what / where to address from an air tightness pov, an initial test is paramount imo. Yes, by all means have a second one at the end for input into the BER assessment but it is generally too late then if unknown leaks are doscovered when all finished etc are in place.
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Is the airtightness test not just an indication of the overall situation, rather than showing where any issues are? I've always thought fix the obvious problems, then do tests that actually identify where issues lie (I'd love to know more about these), do work, retest for overall airtightness? Or are there different types of tests?
 
Hooverfish said:
Is the airtightness test not just an indication of the overall situation, rather than showing where any issues are? I've always thought fix the obvious problems, then do tests that actually identify where issues lie (I'd love to know more about these), do work, retest for overall airtightness? Or are there different types of tests?
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The issue I find frequently when doing the surveys / tests is that the "obvious" problems to the client are rarely the main issues leading to somewhat wasted effort & resources by the client.
You are correct in that the official air tightness test does give an overall result which represents the air tightness of the building. However, not simultaneously investigating the cause of the leakage when set up to carry out the depressurisation of the building is, imo, a wasted opportunity to garner maximum information from the test (and value for money).
 
We got a full deep retrofit including a heat pump to take house from a D2/3 to a A2. However, I'd argue we've gained most of the benefit from the insulation and new windows. I would not be rushing to get a heat pump.
- Not cheaper (so far the bills are more expensive - I'm basing this on energy used not cost. But I'm not comparing like with like due to working from home, and haven't had a full year yet. For reference we've heating set to 16-18 degrees, lower the temperature at night and have a solar panel. I suspect that the hot water is set to come on more than we need and when I get time I'll do a bit more investigating - though we were strongly recommended not to change the settings for it)
- Radiators are physically quite a bit bigger for use with heat pump, with small rooms its quite a big difference.
- We've had issues with our water since upgrade (problem with differences in pressure from heat pump? / an installation/design problem, or something historic in our system that only happened when we upgraded - 4-6 months later still working with installer on root cause) This is a risk with any building work that there are problems.
- Less flexible (heats up slower. They say that this means houses don't go through the swings of being too hot / cold, but I'd put most of the differences down to the insulation versus the heating - if you try and heat it quicker its more expensive, most efficient at a steady heat)
- More of a design issue, but one to consider, if a zone is balanced, but the rooms aren't you still end up with cold/hot rooms - we'll probably be able to tweak this over time, but not as easy as before.

If we'd got the insulation done and not upgraded heating, we'd have a system where rooms heated up quicker at a lower cost. We got a grant, so the extra cost of the heat pump was somewhat offset, but I'm really not so sure yet that it was worth it to us. I'm interested to see how the costs work out over summer. We'd figured we were doing the under floor insulation, etc... so while everything's up, do it all at once. I certainly wouldn't consider it outside of this. But maybe ask me next autumn what I think.
 
dem_syhp said:
- Not cheaper (so far the bills are more expensive - I'm basing this on energy used not cost. But I'm not comparing like with like due to working from home, and haven't had a full year yet. For reference we've heating set to 16-18 degrees, lower the temperature at night and have a solar panel. I suspect that the hot water is set to come on more than we need and when I get time I'll do a bit more investigating - though we were strongly recommended not to change the settings for it)
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That cannot be correct. If your home has genuinely gone from a D2 to A2, your energy use should be a fraction of what it previously was regardless of the type of heating system. Are you excluding the fact that with a heat pump you are now electricity only and have no gas bill??

It sounds like you are not using your heating system properly or you were poorly advised during the renovation. Generally it does not make sense (cost/benefit) to have both a heat pump and solar panels. Heat pumps are an extremely efficient way to heat water particularly during summer months when air temperatures are higher and the COP is high. Your heating system should not really come on during those months particularly in an A rated home, its usually the opposite, trying to get retained heat out of the house in summer months. So your electricity usage should be very low at a time when your solar panels can generate an excess.

Solar panels are not as effective during winter months when your heat pump is actually heating your home so they are generally wasted cost and effort. They over supply in summer months and massively under supply in winter months. They make more sense when combined with gas heating
 
_OkGo_ said:
Generally it does not make sense (cost/benefit) to have both a heat pump and solar panels.
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They probably have photovoltaic panels, which would make more sense with a heat pump (offsetting the electricity the heat pump uses) than the solar tubes for hot water.
 
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