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Heat Pumps - post here.

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Comments

  • Registered Users Posts: 119 ✭✭WLad


    KCross wrote: »
    HP's dont really work that way. If you are sending it a signal at 5pm to have a room warm for you by 6pm you are going to be disappointed. HP's need hours to build up the UFH temp and then release it.

    You are thinking of the old style oil burner and rad type system where you turn it on and it fires out 60C heat within minutes. HP's deliver <30C to the UFH and then it takes time for that to "seep" through to the house.

    You shouldnt really be turning anything on or off on the heat pump. Set it to the temp that is comfortable for you and your house and then let the HP manage that itself.

    Ah. Ours is on oversized rads instead but the principal is similar if just less efficient I suppose. Ok well at least I know anyway. Thanks.


  • Registered Users, Registered Users 2 Posts: 3,610 ✭✭✭John.G


    Carrickbeg wrote: »
    12 - 15 cents to heat 280L of hot water? That's 1kwh on my electricity charges...

    Friend of mine has just returned from Co Kerry where he was visiting people in a new build with what he thinks is the above system.
    It is put together by a firm based in Little Island in Cork and apparently has a fairly conventional A2W outdoor/indoor system supplying low temperature hot water to the UFH which is installed both upstairs and downstairs.
    The domestic hot water is supplied from a unit with its own compressor and a 300 litre hot water cylinder and utilizes exhaust air from the kitchen area which is then expelled to the outside.


  • Registered Users Posts: 8 BFMadden


    Guys,

    Has anyone any experience of an Ovum heat pump and DHW system? They're an Austrian brand that is supplied and installed by Climate Control in Galway. Looks good but there's very little info on it.

    ovum.at

    Open link with Chrome to translate.

    Thanks


  • Closed Accounts Posts: 18,958 ✭✭✭✭Shefwedfan


    Just wondering are many people using A2W heat pump with standard radiators? it seems most companies now have option


  • Closed Accounts Posts: 844 ✭✭✭H.E. Pennypacker


    Shefwedfan wrote: »
    Just wondering are many people using A2W heat pump with standard radiators? it seems most companies now have option


    I've had a few quotes for A2W retrofit. Most companies who have experience with this are happy to talk about a potential multi-step approach where the customer can try the HP with existing radiators. One suggested running the existing OFCH at 40C supply to see how it goes. Its not ideal if you'd like to maximise the lifespan of your existing boiler but as a stepping stone its a very useful insight.

    The biggest issue that I've found is that the companies most willing to deal aren't yet SEAI approved for grant purposes. It requires FETAC Level 6 plumbers and a lot of companies are aircon, not plumbing companies. That said, the SEAI requirements are very relevant for a retrofit scenario in terms of the fabric first approach and in my experience, they tend to maintain standards with contractors. You would need to have confidence in the heat loss attributes of your house and without a heat loss indicator of max 2.2 for retrofit you can't say for sure that it'll pay.


  • Registered Users, Registered Users 2 Posts: 455 ✭✭zoom_cool


    Does anybody have Firebird offering of AWH pump sister is building new house and got a quotation and they where very competitive. The system is called Enviroair Hybrid Heatpump which has a oil burner as a backup.


  • Registered Users, Registered Users 2 Posts: 3,610 ✭✭✭John.G


    zoom_cool wrote: »
    Does anybody have Firebird offering of AWH pump sister is building new house and got a quotation and they where very competitive. The system is called Enviroair Hybrid Heatpump which has a oil burner as a backup.

    Grant do a similar Hybrid which can be used for comparison purposes if not all ready done so.


  • Registered Users, Registered Users 2 Posts: 12,152 ✭✭✭✭KCross


    zoom_cool wrote: »
    Does anybody have Firebird offering of AWH pump sister is building new house and got a quotation and they where very competitive. The system is called Enviroair Hybrid Heatpump which has a oil burner as a backup.

    I dont have experience with them but they seem like something you would install as a retrofit rather than something for a new house where you have high levels of insulation, air-tightness and heat recovery ventilation.

    i.e. Why would you install a hybrid system that will be more complex and likely to be less reliable in the long term and have to continue to pay for oil.

    Unless it was significantly cheaper it would make more sense to me, in a new build partiularly, to just install a correctly sized heat pump and leave it at that.


  • Registered Users, Registered Users 2 Posts: 455 ✭✭zoom_cool


    There is some smart logic so when it is more efficient to run oil boiler it will. The price was competitive same and cheaper to some standalone heat pump quotations.


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  • Registered Users, Registered Users 2 Posts: 12,152 ✭✭✭✭KCross


    zoom_cool wrote: »
    There is some smart logic so when it is more efficient to run oil boiler it will. The price was competitive same and cheaper to some standalone heat pump quotations.

    But it will be a more complex system and you have to have an oil tank and oil burner and it will need more servicing and you have to order oil etc etc.... I just dont see why you would do that over having a single heat pump system in a new build house. I just dont see the advantages (smart controls or not) outweighing the disadvantages unless the price differential was significant

    Note, you can tweak heat pump settings to take advantage of night rate electricity as well. You cant run it entirely at night but you can limit it and in a new build, with low heat demand, I dont think oil should be considered at all, imo.

    For a retrofit it might make sense.


    For a new build you should be looking to get as much of your consumption onto electricity as you can with an eye to SolarPV. Putting in oil in a 2019 house is questionable,again imo.


  • Registered Users, Registered Users 2 Posts: 9,815 ✭✭✭antoinolachtnai


    i would be concerned about the pricing here. At the end of the day this is a more complex unit that is more expensive to manufacture and commission compared to a heat pump.

    The heat requirement of a new build should be quite low and you should be able to get a heat pump to cover it. And it should be cheaper than this unit.

    This unit makes sense in a situation where the heat requirement can be met by the heat pump most of the year, but an oil boost is only required a few days a year on the coldest days.

    You also have to take account of the cost of an oil tank and the issues around deliveries. And the extra maintenance requirements.


  • Registered Users, Registered Users 2 Posts: 455 ✭✭zoom_cool


    KCross wrote: »
    But it will be a more complex system and you have to have an oil tank and oil burner and it will need more servicing and you have to order oil etc etc.... I just dont see why you would do that over having a single heat pump system in a new build house. I just dont see the advantage (smart controls or not) outweighing the disadvantages unless the price differential was significant.

    Note, you can tweak heat pump settings to take advantage of night rate electricity as well. You cant run it entirely at night but you can limit it and in a new build, with low heat demand, I dont think oil should be considered at all, imo.

    For a retrofit it might make sense.


    For a new build you should be lookng to get as much of your consumption onto electricity as you can with an eye to SolarPV. Putting in oil in a 2019 house is questionable,again imo.

    Thanks KCross what are the best heat pumps out there is it Danfoss, Daikin, Nibe etc.


  • Registered Users, Registered Users 2 Posts: 676 ✭✭✭mjsc1970


    Hi.
    I've moved in to an A rated new build with A2W Dimplex Heat Pump set up. Am trying to get to grips with it and what's the most effecient way to use it.

    I've the HotWater timed for twice a day and this sorts all our households needs for the day. Maybe it's on for too long as I don't seem to ever run out of warm water.

    But, as regards house/space heating I've not quite got to grips with. Without the heating on, house is comfortable at 20.5C. When it drops below this I tend to manually put the boiler on to heat the rads up to 22C. My question is, is it more effeciant to leave the boiler ON constantly, so as, when internal temperature drops below a certain limit, the space heating kicks on and automatically brings the heating temperature up to a comfortable level in which case it would kick in automatically when target temperature drops and off when target temperature is reached. Is this the best way to operate?


  • Registered Users, Registered Users 2 Posts: 12,152 ✭✭✭✭KCross


    zoom_cool wrote: »
    Thanks KCross what are the best heat pumps out there is it Danfoss, Daikin, Nibe etc.

    The service guys on the forum will need to answer that. I dont know. I have a Nibe myself (but Geothermal, not A2W) and it has been low maintenance for the last 7yrs (one €200 component died and no other costs other than the electricity, of course).


  • Closed Accounts Posts: 18,958 ✭✭✭✭Shefwedfan


    I've had a few quotes for A2W retrofit. Most companies who have experience with this are happy to talk about a potential multi-step approach where the customer can try the HP with existing radiators. One suggested running the existing OFCH at 40C supply to see how it goes. Its not ideal if you'd like to maximise the lifespan of your existing boiler but as a stepping stone its a very useful insight.

    The biggest issue that I've found is that the companies most willing to deal aren't yet SEAI approved for grant purposes. It requires FETAC Level 6 plumbers and a lot of companies are aircon, not plumbing companies. That said, the SEAI requirements are very relevant for a retrofit scenario in terms of the fabric first approach and in my experience, they tend to maintain standards with contractors. You would need to have confidence in the heat loss attributes of your house and without a heat loss indicator of max 2.2 for retrofit you can't say for sure that it'll pay.


    Thanks, I am talking to a company who mentioned a 16kW NIBE 2040 A2W heat pump.



    Keep the oil boiler as a back up. They have connection box



    THey have a installer who is certified and also can do the SEAI grant. This would potentially make sense as the current radiators etc they say will work with the system because they are new and all the piping has high insulation.



    I seen a few companies around offering similar solution but this seems like good option. Just wondering if anyone is actually doing?



    You mention running the boiler at 40 degree, does the A2W not run at 60 degree?


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  • Closed Accounts Posts: 18,958 ✭✭✭✭Shefwedfan


    zoom_cool wrote: »
    Does anybody have Firebird offering of AWH pump sister is building new house and got a quotation and they where very competitive. The system is called Enviroair Hybrid Heatpump which has a oil burner as a backup.


    If doing a new build then a hybrid system is a waste of time. I would go full heat pump. Oil prices will only go one way....


    I have a house built so as a retrofit this is what I would look at.....


  • Registered Users, Registered Users 2 Posts: 12,152 ✭✭✭✭KCross


    Shefwedfan wrote: »
    You mention running the boiler at 40 degree, does the A2W not run at 60 degree?

    Heat pumps are designed to run at ~30C at the distribution point (underfloor, rads etc)
    If you run it at 60C you will significantly shorten its lifespan.

    This design is exactly why they are not recommended for traditional rads. They are designed for underfloor heating where 30C around the entire house floor area is good enough to heat the house but 30C in a stainless steel rad under a window will feel cold to the touch and wont radiate enough heat to make a difference.

    Thread carefully if considering using a heat pump with stainless steel rads.


  • Closed Accounts Posts: 18,958 ✭✭✭✭Shefwedfan


    KCross wrote: »
    Heat pumps are designed to run at ~30C at the distribution point (underfloor, rads etc)
    If you run it at 60C you will significantly shorten its lifespan.

    This design is exactly why they are not recommended for traditional rads. They are designed for underfloor heating where 30C around the entire house floor area is good enough to heat the house but 30C in a stainless steel rad under a window will feel cold to the touch and wont radiate enough heat to make a difference.

    Thread carefully if considering using a heat pump with stainless steel rads.

    Sorry with all the numbers from the guy I got mixed up. Yes it can run at 58 degree but that is the max. As you say the standard is around 30 degree constant.

    I have checked my current boiler and it says on spec sheet: Boiler Thermostat Range: 65 to 80 degree. So I guess the minimum I can set this to is 65 degree.

    It is not just the heat pump, this is the solution
    https://www.nibe.eu/Products/AirWater-heat-pumps/NIBE-F2040/NIBE-F2040--VVM-310/


  • Registered Users, Registered Users 2 Posts: 455 ✭✭zoom_cool


    Just so there is some info here is the details of the Hybrid setup Firebird offer

    https://www.firebird.ie/images/pdf/Enviroair_Oil_Brochure.pdf


  • Registered Users, Registered Users 2 Posts: 221 ✭✭Latro


    Just a quick update on my all stainless steel rads + heat pump retrofit set up.
    For the whole month of October total electricity consumed 282kWh,
    total heat generated 1236kWh, average COP for the month 4.4.
    Total cost 39 euro.

    https://imgur.com/a/EwGZcSy

    The heat pump is never switched off. The house temp fluctuates between 20.8 to 21.7.

    I still learn the system and tweak it occasionally to squeeze the most out of it. At the moment the weather compensating curve is set at -5 to +15 outdoor which translates to +40 to +30 water flow.

    So far I had only 6-7 defrost cycles. Each of them took about 6 mins.
    They came up when air temperature dropped under 2 degrees.

    Last week was proper cold here. Temperature went down to -3 few times.
    On these days average COP was at about 3.3

    When the temps are above 7-8 degrees outside the heat pump sits constantly at 0.4 kW power consumption. I guess it is the lowest modulation it can achieve.

    https://imgur.com/a/Tep6qdt






    Tep6qdt


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  • Closed Accounts Posts: 18,958 ✭✭✭✭Shefwedfan


    Latro wrote: »
    Just a quick update on my all stainless steel rads + heat pump retrofit set up.
    For the whole month of October total electricity consumed 282kWh,
    total heat generated 1236kWh, average COP for the month 4.4.


    Scrub that....found


  • Registered Users, Registered Users 2 Posts: 221 ✭✭Latro




  • Registered Users, Registered Users 2 Posts: 12,152 ✭✭✭✭KCross


    Shefwedfan wrote: »
    Sorry with all the numbers from the guy I got mixed up. Yes it can run at 58 degree but that is the max. As you say the standard is around 30 degree constant.

    I have checked my current boiler and it says on spec sheet: Boiler Thermostat Range: 65 to 80 degree. So I guess the minimum I can set this to is 65 degree.

    It is not just the heat pump, this is the solution
    https://www.nibe.eu/Products/AirWater-heat-pumps/NIBE-F2040/NIBE-F2040--VVM-310/

    Right, but if you need to run your oil burner today at 65C+ to maintain a comfortable temp in the house and you are using a significant amount of oil you can expect that the HP will struggle to match that as it will be running at 30C. There is a big gap there.

    Draughty houses dont work well with HP's.

    Latro's system works, primarily I assume, because its insulated to within an inch of its life and so 30C at the stainless steel rad is all the house needs.

    How much oil are you burning is the thing and would the money you are considering spending on an A2W be better spent on insulation, airtighness and heat-recovery first?


  • Registered Users, Registered Users 2 Posts: 221 ✭✭Latro


    KCross wrote: »
    Right, but if you need to run your oil burner today at 65C+ to maintain a comfortable temp in the house and you are using a significant amount of oil you can expect that the HP will struggle to match that as it will be running at 30C. There is a big gap there.


    It doesn't necessarily mean that. It depends how long he had those 65C on per day to achieve satisfactory temperature.


    If you run those 65C for lets say 4-5 hours per day there is good chance that running water at 30-40 degrees like myself for 24h will achieve same or better result.
    The comfort would definitely be better as there would be little to no fluctuations in temperature throughout the day.


    If his house is drafty it will be cold and expensive to heat regardless of heating source.


  • Registered Users, Registered Users 2 Posts: 12,152 ✭✭✭✭KCross


    Latro wrote: »
    It doesn't necessarily mean that. It depends how long he had those 65C on per day to achieve satisfactory temperature.

    Exactly, which is why I said: "... and you are using a significant amount of oil..."


  • Closed Accounts Posts: 844 ✭✭✭H.E. Pennypacker


    KCross wrote: »
    Right, but if you need to run your oil burner today at 65C+ to maintain a comfortable temp in the house and you are using a significant amount of oil you can expect that the HP will struggle to match that as it will be running at 30C. There is a big gap there.

    Draughty houses dont work well with HP's.

    Latro's system works, primarily I assume, because its insulated to within an inch of its life and so 30C at the stainless steel rad is all the house needs.

    How much oil are you burning is the thing and would the money you are considering spending on an A2W be better spent on insulation, airtighness and heat-recovery first?


    I fully agree and the SEAI are taking the same approach. Grant conditions are quite strict and its unlikely that an unsuitable house will qualify. The only flaw that I can see is that a door blower test is not mandatory. Money should definitely be spent on every possible fabric upgrade before a heat pump is considered. At that stage, it'd be cheap to run an oil boiler so there's more thought needed then.

    Personally, I don't see the point in a hybrid system. If you need one, you need oil so why not keep it simple and stick with an oil burner.

    Will the SEAI give the grant for a hybrid system? The aim of the grant is to move people away from fossil fuel burning and a hybrid system doesn't achieve that.

    FWIW, my boiler is heating the house quite easily at 40C I assume that its running for longer to do that but its not noticeable and the cycle time seems normal. I don't plan on tearing up floors so I'm planning A2W with rads. I need more certainty around actual heat demand but I'm assuming a COP of 2.5 and the figures work for me at that.


  • Closed Accounts Posts: 18,958 ✭✭✭✭Shefwedfan


    KCross wrote: »
    Right, but if you need to run your oil burner today at 65C+ to maintain a comfortable temp in the house and you are using a significant amount of oil you can expect that the HP will struggle to match that as it will be running at 30C. There is a big gap there.

    Draughty houses dont work well with HP's.

    Latro's system works, primarily I assume, because its insulated to within an inch of its life and so 30C at the stainless steel rad is all the house needs.

    How much oil are you burning is the thing and would the money you are considering spending on an A2W be better spent on insulation, airtighness and heat-recovery first?

    I think worse case i do 2-2.5 fills per year

    I do like a bit of insulation myself.....60% of the house has walls pumped plus then insulated slabs on the walls and ceiling, then ceiling topped up with fiber glass.....I done air tightness on windows etc, put in draft lobby with triple glaze...oh yeah dug up floors and put down 120mm I think of insulation.....

    The other section has just pumped walls and insulation in attic...windows I think the guy said got done in 2006-2009 so newish...was build circa 2009 so “should” have better insulation in floors etc that part had before I done up

    Could maybe top up more in attic but would expect to do that before installation...

    Not a cold house just not a small house......


  • Registered Users, Registered Users 2 Posts: 12,152 ✭✭✭✭KCross


    Considering the amount of insulation you’ve detailed it seems like a lot of oil to still be burning through, notwithstanding it’s a large house.

    An airtighness test or thermal imaging camera might be worth looking into?


  • Registered Users, Registered Users 2 Posts: 3,610 ✭✭✭John.G


    KCross wrote: »
    Considering the amount of insulation you’ve detailed it seems like a lot of oil to still be burning through, notwithstanding it’s a large house.

    An airtighness test or thermal imaging camera might be worth looking into?

    Seems a lot but the heat pump will monitor pretty exactly what the house/hot water heat demand is and will be very interesting and also the weather compensation curve required in very cold weather.
    I have a 145 M2 semi detached house cavity BLOCK! with attic conversion, attic roof very well insulated. No zoning apart from hot water cylinder, TRVs on all rads bar 2 which are on a room thermostat. I run the heating for 15hours/day, SE 20Kw Firebird Heatpac boiler and my average oil consumption for the past 6 years has been 1550 Litrs/year, say 1.5 "fills".


  • Registered Users, Registered Users 2 Posts: 12,152 ✭✭✭✭KCross


    John.G wrote: »
    Seems a lot but the heat pump will monitor pretty exactly what the house/hot water heat demand is and will be very interesting and also the weather compensation curve required in very cold weather.

    I guess what I'm saying is that he seems to have done alot of remedial work to reduce the heat demand but still using alot of oil. I'd try to get the heat demand down further first, by running an airtightness test etc to see where the heat is going to, before forking out €10k for a HP system.

    If he could, for instance, spend €4k on more remedial work and get the oil bill down to one fill it would then be much harder to justify spending the €10k on a HP system as you'd buy alot of oil for that.

    Spending the €10k on the HP and monitoring its usage isnt going to change the heat demand of the house. Its just going to drive his electricity bill up and now he is maintaining two heating sources.


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  • Registered Users, Registered Users 2 Posts: 221 ✭✭Latro


    Shefwedfan burns about 2500L of oil. His house is 285sqm.


    2500L*10kWh*0.8 / 285sqm = 70.1kWh/sqm/year


    Add some electricity usage and that's about B2 in BER rating. Not bad for pre 2008 regs house. It will be very difficult to squeeze more out of it on relatively low cost.


  • Registered Users, Registered Users 2 Posts: 3,610 ✭✭✭John.G


    KCross wrote: »
    I guess what I'm saying is that he seems to have done alot of remedial work to reduce the heat demand but still using alot of oil. I'd try to get the heat demand down further first, by running an airtightness test etc to see where the heat is going to, before forking out €10k for a HP system.

    If he could, for instance, spend €4k on more remedial work and get the oil bill down to one fill it would then be much harder to justify spending the €10k on a HP system as you'd buy alot of oil for that.

    Spending the €10k on the HP and monitoring its usage isnt going to change the heat demand of the house. Its just going to drive his electricity bill up and now he is maintaining two heating sources.

    You are quite correct.
    I got mixed up between Latro & Shefwedfan, its Shefwedfan that uses a lot of oil.
    If he cannot improve on the insulation and he wants a good COP by running at 40C then he will have to install very large rads because assuming a rad delta T of 5C and a required room temperature of 21C will give ((40+35)/2)-21, a "16.5C" rad which will only emit ~ 24% of the heat output of the same rad running as a "50C" rad, (16.5/50)^1.3.
    I suppose thats why retrofitting using existing (or new) rads vs UFH is a big challenge in a house that requires a lot of heat and where you want to get a good COP.


  • Registered Users, Registered Users 2 Posts: 221 ✭✭Latro


    John.G wrote: »
    ...a "16.5C" rad which will only emit ~ 24% of the heat output of the same rad running as a "50C" rad...

    Or he would need to run them about 4 times longer.

    285 sqm is a lot of space to heat. I'm not sure if 12kW HP would be enough. Probably it would but it is a little bit risky move and at 16kW you step into very expensive territory as there are no single phase HPs of that size.


  • Closed Accounts Posts: 18,958 ✭✭✭✭Shefwedfan


    KCross wrote: »
    Considering the amount of insulation you’ve detailed it seems like a lot of oil to still be burning through, notwithstanding it’s a large house.

    An airtighness test or thermal imaging camera might be worth looking into?


    it's not really 2.5 fills. I have upped by half a fill. If I take last winter I would have filled in September(same this year) and then a fill probably in Feb/March. I don't think this was a full 1000 ltr as I had to swap the tank. Which I done during the summer.



    My September fill is still maybe 80%+ full now so I would expect to be ok till Feb.....


    My main issue is my wife....if she had her way the heating would be going 24 x 7 :P A2W would be perfect for her


  • Registered Users, Registered Users 2 Posts: 17,077 ✭✭✭✭banie01


    The A2W heat pump is likely where I see my next home efficiency upgrade being.

    I have a 1980's 3 bed semi and have pumped the walls with bonded bead, topped up the attic and installed triple Glazing.
    Have Nest installed and heating rarely runs for more than 1hr a day.
    I'm reading with interest the posts on radiators as I can't afford installing ufh and would like to keep as much of my existing equipment as possible and the rads are fairly new.

    I'm leaning towards solar hot water, larger hot water tank and A2W. Is there an option to utilise the solar gain for heating? Or is it more efficient to stick with PV and use the electricity to run A2W?


  • Registered Users, Registered Users 2 Posts: 221 ✭✭Latro


    Also he could consider installation of 2 fan coil radiators like those 6kW Irish made Solo range. 1 downstairs (ideally somwhere in open plan) and 1 upstairs (perhaps in landing area). They would greatly improve overall low temperature performance and they would allow for summer cooling. That would set him back extra 700-800 euro.


  • Registered Users, Registered Users 2 Posts: 221 ✭✭Latro


    banie01 wrote: »
    The A2W heat pump is likely where I see my next home efficiency upgrade being.

    I have a 1980's 3 bed semi and have pumped the walls with bonded bead, topped up the attic and installed triple Glazing.
    Have Nest installed and heating rarely runs for more than 1hr a day.
    I'm reading with interest the posts on radiators as I can't afford installing ufh and would like to keep as much of my existing equipment as possible and the rads are fairly new.

    I'm leaning towards solar hot water, larger hot water tank and A2W. Is there an option to utilise the solar gain for heating? Or is it more efficient to stick with PV and use the electricity to run A2W?


    If you really only run oil 1h per day and you happy with the comfort I don't see why you would change to anything else at all. That 1h of oil boiler how much oil consumption does it transfer to?


    If you switch to A2W PV is no brainer imo but would you really need them if your heat pump running cost was at E1.50 per day in the winter and maybe 0.20-0.30 in the summer?


  • Registered Users, Registered Users 2 Posts: 17,077 ✭✭✭✭banie01


    Latro wrote: »
    If you really only run oil 1h per day and you happy with the comfort I don't see why you would change to anything else at all. That 1h of oil boiler how much oil consumption does it transfer to?


    If you switch to A2W PV is no brainer imo but would you really need them if your heat pump running cost was at E1.50 per day in the winter and maybe 0.20-0.30 in the summer?

    It's gas fired but yeah I take your point. My gas is level pay but I'm currently still in credit on that my gas usage is quite low.
    My downstairs is open plan"ish" and a small stove usually takes care of my downstairs heating and even that is run infrequently.

    Your advice is much appreciated.
    It's a change I can push out for a while longer then.


  • Registered Users, Registered Users 2 Posts: 17,077 ✭✭✭✭banie01


    Latro wrote: »
    If you really only run oil 1h per day and you happy with the comfort I don't see why you would change to anything else at all. That 1h of oil boiler how much oil consumption does it transfer to?


    If you switch to A2W PV is no brainer imo but would you really need them if your heat pump running cost was at E1.50 per day in the winter and maybe 0.20-0.30 in the summer?

    It's gas fired but yeah I take your point. My gas is level pay but I'm currently still in credit on that my gas usage is quite low.
    My downstairs is open plan"ish" and a small stove usually takes care of my downstairs heating and even that is run infrequently.

    Your advice is much appreciated.
    It's a change I can push out for a while longer then.


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  • Registered Users, Registered Users 2 Posts: 3,610 ✭✭✭John.G


    Latro wrote: »
    Or he would need to run them about 4 times longer.

    285 sqm is a lot of space to heat. I'm not sure if 12kW HP would be enough. Probably it would but it is a little bit risky move and at 16kW you step into very expensive territory as there are no single phase HPs of that size.

    A bit of zoning would help.

    He would get some idea if he just monitors (listens) to his oil boiler ON cycle times over say a half or one hour period, if the boiler output is known then it is quite easy to calculate the house requirement. For example I know my boiler gives 20 Kw output. Once the house is up to temperature and obviously depending on ambient temperature it cycles ON for anything between 25% to 40% of time which means my requirements are between 5Kw and 8Kw. I know this is a bit rough and ready but it will certainly give some idea if 12 Kw is sufficient and of course a 12 KW unit will only give 5 or 6 Kw in very cold weather.


  • Registered Users, Registered Users 2 Posts: 27,313 ✭✭✭✭GreeBo


    banie01 wrote: »
    The A2W heat pump is likely where I see my next home efficiency upgrade being.

    I have a 1980's 3 bed semi and have pumped the walls with bonded bead, topped up the attic and installed triple Glazing.
    Have Nest installed and heating rarely runs for more than 1hr a day.
    I'm reading with interest the posts on radiators as I can't afford installing ufh and would like to keep as much of my existing equipment as possible and the rads are fairly new.

    I'm leaning towards solar hot water, larger hot water tank and A2W. Is there an option to utilise the solar gain for heating? Or is it more efficient to stick with PV and use the electricity to run A2W?

    I dont see how you are keeping the house warm with 1hr a day of heating?
    What is maintaining the heat in the building if you just have radiators?

    Surely once a window or door is opened all the hot air you heated is gone and you are back to square one?

    Apologies if I missed you have UFH or something else, but right now I dont get it...:o


  • Registered Users, Registered Users 2 Posts: 221 ✭✭Latro


    John.G wrote: »
    A bit of zoning would help.

    He would get some idea if he just monitors (listens) to his oil boiler ON cycle times over say a half or one hour period, if the boiler output is known then it is quite easy to calculate the house requirement. For example I know my boiler gives 20 Kw output. Once the house is up to temperature and obviously depending on ambient temperature it cycles ON for anything between 25% to 40% of time which means my requirements are between 5Kw and 8Kw. I know this is a bit rough and ready but it will certainly give some idea if 12 Kw is sufficient and of course a 12 KW unit will only give 5 or 6 Kw in very cold weather.

    You are being way pessimistic here.

    My heat pump according to manufacturer at water flow 35C has full 9kW power at +7 outdoor, at +2C it has 7.45kW and at -7C 7.70kW.

    Same brand/model but 12kW unit: 12kW at +7, 11.4kW at +2 and 10kW at -7. So at full power run for 24h at -7C and 35 flow it could produce 240kWh of heat and I really doubt he needs anywhere close to that.

    Perhaps installing thermostatic mixing valve and let the oil run for a week non stop at 35-40C would answer the question if it suitable for the house or not.

    Shouldn't be expensive job. The valve probably 70 euro and labor no more than half day worth of work. But who knows these days, plumbers tend to charge and arm and a leg for their services.


  • Registered Users, Registered Users 2 Posts: 17,077 ✭✭✭✭banie01


    GreeBo wrote: »
    I dont see how you are keeping the house warm with 1hr a day of heating?
    What is maintaining the heat in the building if you just have radiators?

    Surely once a window or door is opened all the hot air you heated is gone and you are back to square one?

    Apologies if I missed you have UFH or something else, but right now I dont get it...:o

    Only thing I can think of that's different from standard is an entrance porch.
    No UFH and nest set to 20°, I have noticed a lot more solar gain since installing the triple Glazing tho.


  • Closed Accounts Posts: 18,958 ✭✭✭✭Shefwedfan


    John.G wrote: »
    A bit of zoning would help.

    He would get some idea if he just monitors (listens) to his oil boiler ON cycle times over say a half or one hour period, if the boiler output is known then it is quite easy to calculate the house requirement. For example I know my boiler gives 20 Kw output. Once the house is up to temperature and obviously depending on ambient temperature it cycles ON for anything between 25% to 40% of time which means my requirements are between 5Kw and 8Kw. I know this is a bit rough and ready but it will certainly give some idea if 12 Kw is sufficient and of course a 12 KW unit will only give 5 or 6 Kw in very cold weather.




    The current boiler is Grant Vortex 36-46 Pro Utility. Now this was installed by previous owner, when lets say the 60% of the house I renovated was an ice box. So I personally think it is oversized now for the house.


    The boiler will fire up, fairly soon afterwards if just heating the house will kick off....then it goes in and out to reheat.....no idea how many times or how long it will cycle in & out....

    The house is zoned. Image attached, It has 3 zones and then hot water but the zones are manual valve which is kind of pointless. Also they have a single thermostat running all of the zones :confused: so the heavy lifting is done so to speak and just need some small upgrade to that.


    Just to note from image, the stove is connected to the heating system. One of the installers said the would just disconnect the stove and the A2W would connect into that section. The stove is a Glenmore 30B but on its last legs as previous owner seems to have burned all sorts of s**t in it. So it would be going anyway


  • Registered Users, Registered Users 2 Posts: 3,610 ✭✭✭John.G


    Latro wrote: »
    You are being way pessimistic here.

    My heat pump according to manufacturer at water flow 35C has full 9kW power at +7 outdoor, at +2C it has 7.45kW and at -7C 7.70kW.

    Same brand/model but 12kW unit: 12kW at +7, 11.4kW at +2 and 10kW at -7. So at full power run for 24h at -7C and 35 flow it could produce 240kWh of heat and I really doubt he needs anywhere close to that.

    Perhaps installing thermostatic mixing valve and let the oil run for a week non stop at 35-40C would answer the question if it suitable for the house or not.

    Shouldn't be expensive job. The valve probably 70 euro and labor no more than half day worth of work. But who knows these days, plumbers tend to charge and arm and a leg for their services.

    Yes I was far too pessimistic there, I think Kingspan do a Aeromax 15 KW unit which i presume is single phase but maybe this is only for the UK market.


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  • Registered Users Posts: 1 Jbrod87


    I have a Mitsubishi ecodan system and since the weather has gotten colder it turns on in the middle of the night or early evening depending on how cold it is. But the water and heating are turned off but it still comes on. Is this normal? Also the pumps in the hot press are quiet loud when they turn on. Loud enough to wake you up. Thanks


  • Registered Users, Registered Users 2 Posts: 4,392 ✭✭✭Tefral


    Jbrod87 wrote: »
    I have a Mitsubishi ecodan system and since the weather has gotten colder it turns on in the middle of the night or early evening depending on how cold it is. But the water and heating are turned off but it still comes on. Is this normal? Also the pumps in the hot press are quiet loud when they turn on. Loud enough to wake you up. Thanks

    If your telling me the water and heat are actually off then its the defrost cycle thats happening.

    It uses the hot water from the house to defrost the unit.


  • Registered Users, Registered Users 2 Posts: 8,050 ✭✭✭youcancallmeal


    Jbrod87 wrote: »
    I have a Mitsubishi ecodan system and since the weather has gotten colder it turns on in the middle of the night or early evening depending on how cold it is. But the water and heating are turned off but it still comes on. Is this normal? Also the pumps in the hot press are quiet loud when they turn on. Loud enough to wake you up. Thanks

    Could be a sterilization cycle or even just topping up to maintain water temp


  • Registered Users Posts: 109 ✭✭The Engineer


    My best friend is considering installing this system too. What did you decide in the end?


    BFMadden wrote: »
    Guys,

    Has anyone any experience of an Ovum heat pump and DHW system? They're an Austrian brand that is supplied and installed by Climate Control in Galway. Looks good but there's very little info on it.

    ovum.at

    Open link with Chrome to translate.

    Thanks


  • Closed Accounts Posts: 844 ✭✭✭H.E. Pennypacker


    I'm looking at retrofitting an A2W heat pump to a 1950's house. My heat loss indicator is within limits for the grant, my air leakage figure is 4.6. The house is a 135 sq meter bungalow, no underfloor heating, just steel radiators. The house is very comfortable with the oil fired boiler turned down to achieve a 40C flow temperature. The boiler runs for a max of 6.5 hours out of 24 to keep the house at a comfortable temperature.

    I've had three rough quotes. One suggested a 6 - 8 kWh heat pump, another a 7 - 9 kWh heat pump and the third suggested a 14kWh model. As sizing is critical to getting comfort, running costs and reliability right, is there any way of independently calculating a ballpark suitable size?


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