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Air to air OR air-to-water

  • 13-07-2009 8:22am
    #1
    Registered Users Posts: 80 ✭✭✭ murphyep


    Hello,
    Will have to consider heating supply for my house soon.
    I am considering using a heat pump, either air-to-air or air-to-water?

    Would like to hear any pros and cons from these please...


    Thanks,
    Eddie!


Comments

  • Registered Users Posts: 227 ✭✭ rebellad


    Hi Eddie,

    Just moved into my new build this week and have a Daikin Altherma Air to Water heating system in it. We have UFH up and down in a 2700 sq ft 2 storey. So far so good with the system, have had it going for well over 2 months now and no problem with it. Did a good bit of research when looking into the heating system and got a good few quotes. Heard good things and bad things about the whole geothermal and air to water setups, but in the end decided to bite the bullet after all the research went with the Air to Water. Regarding electricity consumption I guess I can't really give a good view of it until we have been through a winter to see what the effiecency is like .Best of luck


  • Registered Users Posts: 4,751 ✭✭✭ Do-more


    The drawback with any airsource heatpump in Ireland is iceing up.

    Essentially what happens is the heatpump stirps the heat from the air (I think about 7 degrees) When the ambient temperature is high enough this doesn't cause a problem but when ambient temperatures drop below 7 degrees and you are then stripping away 7 degrees then obviously you have the air coming off the heatpump at freezing point and iceing may start to occour.

    In Nordic countries where air source heat pumps are popular this isn't such a problem as humidity levels tend to be comparitively low, but in dear old damp Ireland it can cause quite a problem.

    There are various different methods of de-iceing used by the various different manufacturers but essentially all of them use up energy in some way and this is what can lead to high running costs for air source heatpumps in the Irish climate.

    One possible strategy to overcome this is to pre-heat the incoming air to the heatpump by installing an "earth tube" which is a pretty simple operation. A large pipe is placed about a metre underground and the air is drawn through the pipe prior to the heatpump so that the air is warmed by the ground. If you can keep the heat pump from iceing in cold weather than you will radically reduce the running costs in cold weather.

    I saw this being used on a project on "Grand Designs" on TV a few years back but haven't come accross it being used here yet.

    I'd like to find out more about it, as if possible, I'd like to use such a system on my next build, so if anyone could provide additional information it would be great.

    invest4deepvalue.com



  • Closed Accounts Posts: 193 ✭✭ Stratocaster


    I never even knew there was a renewable energy section. I have been involved with geothermal and air to water since they first became introduced in Ireland. I have been making some suggestions to site moderators as plumbing and heating subjects seem to be spread all over boards.ie I wish they could draw all these subjects together in some form.

    I have worked on some really expensive projects with geothermal heat pumps combined with air to water and geothermal combined with air recovery.

    When considering geothermal or air to water you really have to sit down and do your home work. Most of the providers of these systems are very happy to sell them but when customer's are experiencing problems you will start to see a different side.

    The systems are designed to clients requests so you really need to know exactly what your looking for. You should sit down and work out what your hot water requirement should be, what kind of room temperature you require throughout the house, how much are you willing to pay towards electricity, how much of area are you willing to sacrifice for all the units, how well will you be able to control a highly sophisticated control system.

    The reason I state this, I have installed many systems correctly in accordance with the clients requests but the clients have discovered some factors later on and became unhappy, should they have notified the company's I had been working for with a full well thought out requirement list, a more suitable system would have been installed.

    Most issues I find are to do with over all control of heat and lack of hot water storage.

    You have to forget everything you know about traditional oil and gas heating systems. These systems are in a world of there own.

    I would prefer ground source geo over air source as I don't believe you get the most out of air source.

    These systems cost a lot to install and the whole idea is to reduce bills and recoup the installation cost. If you have an under performing system you wont recoup the costs, may take some time, which defeats the purpose.


  • Closed Accounts Posts: 4 Alexandr


    I never even knew there was a renewable energy section. I have been involved with geothermal and air to water since they first became introduced in Ireland. I have been making some suggestions to site moderators as plumbing and heating subjects seem to be spread all over boards.ie I wish they could draw all these subjects together in some form.

    I have worked on some really expensive projects with geothermal heat pumps combined with air to water and geothermal combined with air recovery.

    When considering geothermal or air to water you really have to sit down and do your home work. Most of the providers of these systems are very happy to sell them but when customer's are experiencing problems you will start to see a different side.

    The systems are designed to clients requests so you really need to know exactly what your looking for. You should sit down and work out what your hot water requirement should be, what kind of room temperature you require throughout the house, how much are you willing to pay towards electricity, how much of area are you willing to sacrifice for all the units, how well will you be able to control a highly sophisticated control system.

    The reason I state this, I have installed many systems correctly in accordance with the clients requests but the clients have discovered some factors later on and became unhappy, should they have notified the company's I had been working for with a full well thought out requirement list, a more suitable system would have been installed.

    Most issues I find are to do with over all control of heat and lack of hot water storage.

    You have to forget everything you know about traditional oil and gas heating systems. These systems are in a world of there own.

    I would prefer ground source geo over air source as I don't believe you get the most out of air source.

    These systems cost a lot to install and the whole idea is to reduce bills and recoup the installation cost. If you have an under performing system you wont recoup the costs, may take some time, which defeats the purpose.


    Absolutely agree. I assume, that most customers can't even imagine what electricity bills they are going to pay later)))
    Geotermal energy, hmm.. sounds nice, but I do believe it can work for Iceland, where they have hot waters coming close to the earth surface, but not for Ireland. In any other case proper installation will cost a lot. Have to make a VERY deep hole.
    By the way, heating pumps are at every house :D just take a look at your fridge


  • Registered Users Posts: 4 pout1


    HI

    I am trying to determine if I have high bills or this is what I should expect for AIR 2 Water

    From 19th Nov to 19 jan we used 2441 KW

    Now our bill before this was estimated on 709 KW, so usage could been less

    Can any one advise how much KW should be expect to use with a 2700 SQ ft house


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  • Registered Users Posts: 181 ✭✭ bfclancy


    you are at 4-6 times the usage i am at for a similar sized house


  • Registered Users Posts: 4 pout1


    Thanks bf Clancy, what should I expect t use per day ?

    I need to figure out what driving it up .

    I have bedrooms at 19

    and downstairs 21

    on all time

    Any ideas?


  • Registered Users Posts: 181 ✭✭ bfclancy


    well i use between 400 and 700 kwh in a two month billing period, but i don't have air 2 water so not comparable but gives you an idea how much your air 2 water unit is consuming. obviously something wrong if consuming that much, anecdotally from what i've seen on this site units would not be consuming anywhere near that much


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