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Heat Pumps - post here.

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  • Registered Users Posts: 467 ✭✭JonMac


    We have a Samsung system; baths are great but run only the hot water, adding some cold if needed.
    Heat pumps like to have the room set at a relatively constant temperature; don't think the cold room, window open will work great,
    We were fine with -2C.


  • Registered Users Posts: 10,708 ✭✭✭✭the_amazing_raisin


    DubLad69 wrote: »
    Hey guys,

    We are considering buying a new build with a dimplex Air to Water Heat pump and underfloor heating. We are concerned about a few things.

    1. Does the water get hot enough for a really hot bath/shower?

    2. How slow to respond is the system? I love going to bed in a cold room, and usually leave the window open. With my current gas boiler and a nest, I can still wake up in a warm room. Will this be possible with a heat pump system?

    3. Will the house stay warm even if it gets to minus 3 outside?

    My advice, don't get a Dimplex, they just don't have the experience of other manufacturers and I'm not convinced you'll get a good lifetime out of them. They've been out twice to change relays on mine because they found a fire risk

    As for the rest of your questions, here's my experience

    1. I'm guessing you want a shower around 60C to count as really hot? A heat pump can heat water to this level but it will be very inefficient as it'll often need to use the immersion heater to boost the last few degrees. My hot water is set to 48C which gives a decent hot shower. Once a week it runs the sterilisation cycle which heats the water to 60C and I generally have a shower after this, I like the odd scalding shower as well

    2. They can respond fairly quickly, but again it'll lower the efficiency of the system dramatically. The best way to operate a heat pump I've found is to have it at a fairly constant temperature all through the night, it'll come on when it's needed to keep the house at that setpoint

    3. Most heat pumps can operate down to minus 20, albeit at lower efficiency. Remember a heat pump works against normal heat flow, it can heat something warm using something cold (it's a bit weird, I know). So unless it hits absolute zero outside, there's still heat energy in the air for the heat pump to extract and heat your house with. A lot of them also have an electric heater to boost the water temperature if the heat pump is struggling

    The key thing to look at is the insulation in your house. If your insulation is crap then your heating system is automatically inefficient because it's going to be working hard all the time to replace the lost heat.

    Even if you have enough insulation, spend time looking into airtightness and ventilation, one air gap in a wall will make all the insulation useless.

    Once you have a well insulated and airtight house, then the heating system will perform efficiently

    Heat pumps tend to work well for slower changes in temperature. The logic is kind of opposite to how most people use gas or oil heating, where they'll have the heating on for an hour or two and the house rapidly heats until it's stifling, and then the heating is off until the house is freezing

    With a heat pump, it's better to leave it on and control the temperature using thermostats. If the house is efficient, then the heat pump won't be heavily loaded and will be very efficient in turn

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



  • Registered Users Posts: 2,876 ✭✭✭Borzoi


    . which heats the water to 60C and I generally have a shower after this, I like the odd scalding shower as well

    60C water will deliver 2nd degree burns in 5 seconds for most people.
    You probably have an anti scald valve on the outlet of the tank which limits the actual temp to about 43-45C, which while uncomfortable for most won't scald


  • Registered Users Posts: 10,708 ✭✭✭✭the_amazing_raisin


    Borzoi wrote: »
    60C water will deliver 2nd degree burns in 5 seconds for most people.
    You probably have an anti scald valve on the outlet of the tank which limits the actual temp to about 43-45C, which while uncomfortable for most won't scald

    Yes correct, fair point, shower has thermostatic control so closer to 50C

    The hot water is set to 48C and I find at the highest temp the shower never gets really hot. It's fine for me, but I do like the odd high temp shower when the water has finished sterilisation

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



  • Registered Users Posts: 116 ✭✭MENACE2010


    Anyone tried programming there heat pump to run ufh on the night rate tariff and if so did it pull down the average daily consumption.

    My Danfoss does allow the hot water to be timed to go on the night rate but not the heating.

    I’m guessing it’s an efficiency thing to maintain the temp of the floors as opposed to long on off cycles

    Hi, we have day/night meter and generate hot water from 11 PM to 9Am..(depending on the need) , heating initially I had it turned down during the day and turned up during evening / night but that turned out not so clever.. house tended to get to warm when we do not need it ( we're in bed) . So I have now the heat pump set that it gradually heats the house , and covers for the heatloss during the day. It all depends how hot you want the house to be though.. underfloor heating however takes it time to flex the temprature though.


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  • Registered Users Posts: 116 ✭✭MENACE2010


    DubLad69 wrote: »
    Hey guys,

    We are considering buying a new build with a dimplex Air to Water Heat pump and underfloor heating. We are concerned about a few things.

    1. Does the water get hot enough for a really hot bath/shower?

    2. How slow to respond is the system? I love going to bed in a cold room, and usually leave the window open. With my current gas boiler and a nest, I can still wake up in a warm room. Will this be possible with a heat pump system?

    3. Will the house stay warm even if it gets to minus 3 outside?

    As stated earlier ..
    1. yes .. most heatpumps have an legionaire disease prevention where the water tank will be "boosted" over 69 degrees C. We have a heatpump now for over 7 years.. works a treat.

    2. with a radiator system yes you could, with a underfloor heating is a no.. it will take its time. If your underfloor has separate loops you could limit the flow to the rooms. In our rooms its 18 degrees during the day/night. Downstairs its 19 degrees on average .. but it depends on the insulation as well. .heatloss is quote low in our house.. Spring time /summer sees a bit of sun warming the house

    3. Yes heat pumps work in the frozen cold.. one thing to remember ..its less effective in freezing temperature's.. you pay for more electricity to get the same amount of heat.. in the house .. those days are an exception though.. my recommendation would be to go on level pay with one of the electricity providers to level out bills . ( works for me to pay a fixed charge .. rather than be taken by a sudden frost spell... )

    Overall very happy with this. leaving behind the days of oil orders .. forgetting oil orders etc..


  • Registered Users Posts: 54 ✭✭lightson


    Air 2 air heat pumps. Been looking at them as a heating option. Never use the old oil boiler just stove for years but fancy some easy heat. Thinking diy just for downstairs as have knocked a wall and is fairly open plan.
    Has anyone gone this route experience with them not that popular hear but def in other parts of world. Relatively cheap and efficient also seems simple not very disruptive to instal.


  • Registered Users Posts: 12,141 ✭✭✭✭Calahonda52


    lightson wrote: »
    Air 2 air heat pumps. Been looking at them as a heating option. Never use the old oil boiler just stove for years but fancy some easy heat. Thinking diy just for downstairs as have knocked a wall and is fairly open plan.
    Has anyone gone this route experience with them not that popular hear but def in other parts of world. Relatively cheap and efficient also seems simple not very disruptive to instal.

    How airtight and insulated is the house?
    Are you applying for a grant?
    will be 600,000 installed in next few years so you are right, not as popular as facebook

    “I can’t pay my staff or mortgage with instagram likes”.



  • Registered Users Posts: 54 ✭✭lightson


    How airtight and insulated is the house?
    Are you applying for a grant?
    will be 600,000 installed in next few years so you are right, not as popular as facebook

    Air to air. Not air to water is what I’m talking about.


  • Registered Users Posts: 10,708 ✭✭✭✭the_amazing_raisin


    lightson wrote: »
    Air to air. Not air to water is what I’m talking about.

    I think what he's trying to say is that the money may be better spent on improving your insulation than buying an heat pump

    Houses with poor insulation and airtightness will need a lot of heat to make up for the constant losses. This is why you can have radiator temperatures close to boiling in some houses, they're overproducing heat to compensate for all the lost heat.

    Even if the insulation is good, poor airtightness will cause all the nice warm air from your heating to just leak out the walls

    In general heat pumps aren't great in poorly insulated properties because they can't produce the same temperatures as oil or gas systems, as so they can't keep up with the losses

    An air-to-air system could be even more affected, since they heating source will be located close to the main source of air leaks (windows/door seals).

    So instead of heating your room, it could just be heating the outdoors

    Having said that, I've not much experience with them, but I'd be interested in how you fare because I'd like to get rid of my rads at some point and an air-to-air system is one alternative

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



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  • Registered Users Posts: 116 ✭✭MENACE2010


    lightson wrote: »
    Air to air. Not air to water is what I’m talking about.

    Air to Air will need a good bit of work , you still have the unit outside and a unit inside. Initially when we planned for the house we build I looked at all options .. even infrared panels.

    The challenge is going to be that you will get cold spots.. on places where you do not want them. Also one of reasons underfloor for heat pump is great is that the floor will act like a heat "battery" it will emit warmth for a longer period of time at a lower temperature..

    Air to Air.. think hair dryer.. you will create a hot flow of air in the house that will inevitably will travel upwards .. ( ceiling) .. it will work to "get the chill out of the house" but an Irish damp winter in a house that is not insulated enough and not draft proof you will struggle to get it warm enough.


  • Registered Users Posts: 237 ✭✭ShanE90


    I retrofitted two 6kW floor mounted heat pumps to my in-laws house this time last year and it has transformed there house. One is in the main living area which is a big kitchen/diner the other is in the hall under the stairs...there acting like fan assisted radiators and are doing 90% of the heating requirement with the added benefit of cooling in summer, the other 10% is provided by a Stanley range on very cold days. The house is approx 2200sqft 5bed dormer built in the 90s not particularly well insulated, running costs per week in winter months were €25-30...so yes it can be done as an alternative to A2W


  • Registered Users Posts: 12,141 ✭✭✭✭Calahonda52


    ShanE90 wrote: »
    I retrofitted two 6kW floor mounted heat pumps to my in-laws house this time last year and it has transformed there house. One is in the main living area which is a big kitchen/diner the other is in the hall under the stairs...there acting like fan assisted radiators and are doing 90% of the heating requirement with the added benefit of cooling in summer, the other 10% is provided by a Stanley range on very cold days. The house is approx 2200sqft 5bed dormer built in the 90s not particularly well insulated, running costs per week in winter months were €25-30...so yes it can be done as an alternative to A2W
    €140/ month is not cheap and to say that the stanley does 10% as a sort of thermal backup is stretching it a bit, the the two A2A are c 36Kw output.

    “I can’t pay my staff or mortgage with instagram likes”.



  • Registered Users Posts: 10,708 ✭✭✭✭the_amazing_raisin


    ShanE90 wrote: »
    I retrofitted two 6kW floor mounted heat pumps to my in-laws house this time last year and it has transformed there house. One is in the main living area which is a big kitchen/diner the other is in the hall under the stairs...there acting like fan assisted radiators and are doing 90% of the heating requirement with the added benefit of cooling in summer, the other 10% is provided by a Stanley range on very cold days. The house is approx 2200sqft 5bed dormer built in the 90s not particularly well insulated, running costs per week in winter months were €25-30...so yes it can be done as an alternative to A2W

    Interesting, can you send on what make & model of heat pump you used? You can PM me if you don't want to post details here

    I'm guessing they're a kind of self contained unit, like the window mounted air conditioners you see in the US?

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



  • Registered Users Posts: 3,292 ✭✭✭0lddog


    €140/ month is not cheap and to say that the stanley does 10% as a sort of thermal backup is stretching it a bit, the the two A2A are c 36Kw output.


    I have to look after a 40's dormer of about 1800sqft and did similar to ShaneE90. Actually the cost per week works out as about the same as his ( thats running 24 X 7 in winter weather ). Previously house cost around 6k per year to heat ( using LPG ) The house was never truly warm as LPG wasnt on 24 X 7. So all in all HP considered a good move :)


  • Registered Users Posts: 177 ✭✭ercork


    I fitted an A2A in my small 2 bed end of terrace house about four years ago. It does a great job. Costs a fraction of what the previous electric heating cost.


  • Registered Users Posts: 237 ✭✭ShanE90


    €140/ month is not cheap and to say that the stanley does 10% as a sort of thermal backup is stretching it a bit, the the two A2A are c 36Kw output.

    The two units are providing 6kW of heat each, they are not intended to provide all the heat required, the Stanley is used to provide hot water and heat the far bedrooms if needed. In this situation it provides someone living in there late 70s, with almost instant heat as oppose to cutting collecting chopping timber and hauling it into the house with the addition of coal also.


  • Registered Users Posts: 54 ✭✭lightson


    Yeh I get that they work most efficiently at lower temps. I have a semi d with a basement I h as be filled the floor joists and covered on underside with breather membrane. All down rooms have calked or foamed voids have no s as if vents except trickle vents on basic triple glasses windows doors are basic souls glassed roof ceiling has near 2 foot of insulation. Walks are crap with 40mm polystyrene. Haven’t block to of cavity or got the small void pumped but contemplating it. House is very dry.
    I just looking for additional efficient easy heat source. Am near coast which is a concern regards longevity of a heat pump fan exchanger.
    Interesting thought ref cold spots. Suppose thinking of it as a large electric eficient heater.
    Has anyone hear got or lived with a air to air heater pump? As really the idea of blown heat does seem strange especially when coming from high on a wall.


  • Registered Users Posts: 12,141 ✭✭✭✭Calahonda52


    ShanE90 wrote: »
    The two units are providing 6kW of heat each, they are not intended to provide all the heat required, the Stanley is used to provide hot water and heat the far bedrooms if needed. In this situation it provides someone living in there late 70s, with almost instant heat as oppose to cutting collecting chopping timber and hauling it into the house with the addition of coal also.

    So the input power for the heat pumps is maybe 1.5 or 2 kW, assuming a SCOP of maybe 3/3.5., for 2,200 fully heated at 21 degrees all year round?
    or are they just glorified fan headers.
    can yon tell us the make model pls?

    “I can’t pay my staff or mortgage with instagram likes”.



  • Registered Users Posts: 10,708 ✭✭✭✭the_amazing_raisin


    lightson wrote: »
    Yeh I get that they work most efficiently at lower temps. I have a semi d with a basement I h as be filled the floor joists and covered on underside with breather membrane. All down rooms have calked or foamed voids have no s as if vents except trickle vents on basic triple glasses windows doors are basic souls glassed roof ceiling has near 2 foot of insulation. Walks are crap with 40mm polystyrene. Haven’t block to of cavity or got the small void pumped but contemplating it. House is very dry.
    I just looking for additional efficient easy heat source. Am near coast which is a concern regards longevity of a heat pump fan exchanger.
    Interesting thought ref cold spots. Suppose thinking of it as a large electric eficient heater.
    Has anyone hear got or lived with a air to air heater pump? As really the idea of blown heat does seem strange especially when coming from high on a wall.

    I guess it comes down to cost/benefit and what you can afford currently

    In general spending money on insulation will be better in the long run and it means your heating system will run more efficiently

    As others have noted, in a poorly insulated houses the heating bill can be in the thousands. So even a 10% saving is a fair chunk of cash. It's possible an A2A setup will save some money, but just watch out for the salesman talk. A lot of the marketing material is based on having a high efficiency home to start with

    As for living beside the sea, I remember one A2W heat pump I saw had a special consideration for living on the coast. Basically the worry was that salt water in the air would be driven into the unit by the wind. The solution was to put a wind break in front of it

    I'd read the documentation of any units you're looking at and see if they have any similar requirements

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



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  • Registered Users Posts: 12,141 ✭✭✭✭Calahonda52


    there are marine spec units available, just make sure thats what they install

    “I can’t pay my staff or mortgage with instagram likes”.



  • Registered Users Posts: 54 ✭✭lightson


    I’m thinking of buying and doing (diy) may need a fridge guy to pressure pipes if don’t go Diy kit.
    Really wondering if anyone hear has one in use and how they rate them in our climate as they are a Very different system to underfloor or radiant heat. I visited a house owner was an ex heating engineer and he had 2 one in sitting room and another in a bedroom I think. Not a mini split but 2 separate units and 2 separate compressors on garage roof with long pipe runs round house to the fan units in the rooms. He thought they were great but had bought them used and stupid cheap.
    Thanks for advice about insulation. I thought this was a heat pump thread and a2a heat pumps is my very specific interest. I have only seen one home with them installed! So they are unusual in the irish context however are used on shops and Commercial buildings as they double as air conditioning, cooling and heating


  • Registered Users Posts: 3,292 ✭✭✭0lddog


    lightson wrote: »
    I’m thinking of buying and doing (diy) may need a fridge guy to pressure pipes if don’t go Diy kit.
    Really wondering if anyone hear has one in use and how they rate them in our climate as they are a Very different system to underfloor or radiant heat. .....

    A few points :

    - Note that posts above by Shane and myself relate to retrofit of units. In a renovation project such as yours you have many more options open to you then we had for our houses.

    - If you do decide to use A2A then get units that are designed for heating rather than one designed for cooling. The units designed for heating should give solid performance with outside temperatures of -15C or lower whereas the units designed for cooling struggle in heating mode with outside temp as high as -5C. There are many YT clips by people who use A2A for heating - some in the north central US.

    - For warranty reasons buy whatever brand you decide from an approved installer and get them to do the install. While it may seem more expensive you should find that VAT is charged at the reduced rate - so it sort of balances out.

    - Note that for heating you need to have the indoor units located near floor level. These can be either wall units mounted low down on a wall or units designed for floor mounting

    - FWIW I used products from Mitsubishi Electric from the VEHZ product subset ( sometimes they call this product subset 'hyper heat' or 'hypercore' )


  • Posts: 0 [Deleted User]


    I’ve been interested in building a natural swimming pool for the last few years. It is considerable investment for a “garden feature” so I’m now wondering could I also use it as a pond source geothermal heat pump. This would help justify the cost and I think there would be something really special about having a pond I can swim in in summer and use it to heat my house in winter, while having the natural beauty/wildlife benefit of it all year. I’ve been Googling how big the pond needs to be but I’m getting US sites with their huge houses and many of them in upstate NY. Anyone have experience of doing this in Ireland?


  • Registered Users Posts: 12,030 ✭✭✭✭KCross


    Static water wouldn’t work I’d say in this country. It would just freeze it to ice in the winter and the efficiency would be terrible.

    The heat source needs to be renewable and static water isn’t renewable.


  • Registered Users Posts: 12,141 ✭✭✭✭Calahonda52


    1: it's not geothermal if W2W from a lake, it's ground source.
    2: how many sq kilometres surface area will this be?
    3: whats the average depth?
    4: how will you replenish for leaks/evaporation?
    5: How many cubic kilometres of water do you envisage being in the lake?
    .
    If its big enough then you should be able to over come the issues KC alludes to?

    “I can’t pay my staff or mortgage with instagram likes”.



  • Registered Users Posts: 54 ✭✭lightson


    Thanks interesting having heating unit near floor. The Mitsubishi units you recommend look good and seem focused on low temp efficiency thanks.
    Although vat reduction of total cost can’t be that much.


  • Registered Users Posts: 3,292 ✭✭✭0lddog


    lightson wrote: »
    Thanks interesting having heating unit near floor. The Mitsubishi units you recommend look good and seem focused on low temp efficiency thanks.
    Although vat reduction of total cost can’t be that much.

    I'm not recommending - its just thats what I used.

    Base your Equipment selection on the engineering needs of the project.

    WRT approved installers, in the case of Mitsi I think they give a 5 year warranty if supplied & installed by a Mitsi approved company - its well worth paying a bit to get cover like that !

    In any event the costs seemed pretty OK to me in that I got a couple of ( the VEHZ ) units supplied and installed for something under 5k. I had been looking a replacing a gas boiler at the time. Quotes for this were 4k+


    floor mounted units : https://www.mitsubishicomfort.com/products/indoor-units/floor-mounted/gallery/782

    ( I cheaped out and just put wall mount units about a foot above the floor :D )


  • Registered Users Posts: 10,708 ✭✭✭✭the_amazing_raisin


    MAXFANTANA wrote: »
    I’ve been interested in building a natural swimming pool for the last few years. It is considerable investment for a “garden feature” so I’m now wondering could I also use it as a pond source geothermal heat pump. This would help justify the cost and I think there would be something really special about having a pond I can swim in in summer and use it to heat my house in winter, while having the natural beauty/wildlife benefit of it all year. I’ve been Googling how big the pond needs to be but I’m getting US sites with their huge houses and many of them in upstate NY. Anyone have experience of doing this in Ireland?

    There was a project some time ago about using an underground tank as a thermal battery

    https://www.scanhome.ie/research/solarseasonal.php

    Essentially the water was heated with excess solar energy during the day and then the heat was used in the evenings

    It's not exactly what you're looking for, but I could see it usable in your case if you could have some sort of well insulated cover for the pool to stop the heat escaping

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost



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  • Registered Users Posts: 12,141 ✭✭✭✭Calahonda52


    There was a project some time ago about using an underground tank as a thermal battery

    https://www.scanhome.ie/research/solarseasonal.php

    Essentially the water was heated with excess solar energy during the day and then the heat was used in the evenings

    It's not exactly what you're looking for, but I could see it usable in your case if you could have some sort of well insulated cover for the pool to stop the heat escaping

    TKS for posting this, there is a lad in westmeath who did this with a big precast tank, he had access to a big digger etc..
    he maxed out his solar thermal panels and uses heat pumps.
    It must be there 15 years now and the water is pretty much primordial soup at this stage but works great. I think its a great idea as not heat dumping from the thermal panels and the high delta t between the soup and the panel, heat transfer is good

    “I can’t pay my staff or mortgage with instagram likes”.



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