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Dhw heat pump combined with oil and stove

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  • 17-04-2014 8:09pm
    #1
    sparks3000
    Registered Users Posts: 42 ✭


    Hi I'm currently getting a spec put together for my heating system but I don't want solar panels. I'm just wondering if I put in a domestic hot water heat pump this will only heat water ,this will work all year round and I combined it with oil condensing boiler and a stove with a back boiler . It would have a triple coil stainless steel cylinder 300 litre. Would this be a difficult system to plumb and would it work well in a new build. Any thoughts or comments welcome. The heat pump has a cop of over 4.0 . I don't think I can justify the expense of a heat pump for heating and hot water right now maybe in the future as systems get better I will replace the oil condenser when it reaches the end of its life.


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    #2
    shane 007
    Closed Accounts Posts: 914 ✭✭✭shane 007


    I have an oil condensing boiler with heat pump for dhw only. Works a treat & very inexpensive to run.
    House is 3,000sqft with UFH on both floors & costing approx €810 per year to heat.
    Heat pump for hot water is costing approx 34 cent per day.
    Very happy with both systems.


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    #3
    richieburke01
    Closed Accounts Posts: 217 ✭✭richieburke01


    is that heat pump built into the cylinder on top of it and draws air in from the house:)


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    #4
    sparks3000
    Registered Users Posts: 42 ✭sparks3000


    Sounds very reasonable to run. My house is just under 2000 square feet but I'm not sure about using ufh I prefer radiators. The heat pump I have in mind is mounted beside the cylinder and uses the air in the house


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    #5
    richieburke01
    Closed Accounts Posts: 217 ✭✭richieburke01


    very good i started using that system for heating water seems to be a better job than SOLAR!!!


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    #6
    shane 007
    Closed Accounts Posts: 914 ✭✭✭shane 007


    Mine uses the air from outside. None of them should use the air from the house as they will enormously cool the house. They use 500m3 of air per hour. If not properly catered for, it will dramatically cool the house & possibly create room vacuums.
    I have installed them inlets & outlets directly to external & inlet from ventilated attic & outlet directly to external.

    There is a thread here I posted on the unit with running costs, usage, COP's, etc. Some good knowledgeable guys inputted to the thread also.


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    #7
    sparks3000
    Registered Users Posts: 42 ✭sparks3000


    The heat pump I saw today recovers the air from bathrooms kitchen and a room for drying clothes and the cold air is expelled outside. I'm now wondering could the air be brought in from outside . I will pm the name of the heat pump ,could you pm me the name of the heat pump that you have installed


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    #8
    shane 007
    Closed Accounts Posts: 914 ✭✭✭shane 007


    Sure.
    With something that is taking air from bathrooms, kitchens, drying rooms, etc. I would be asking many questions. These are all rooms that are within the heated envelope of the building & therefore you will increase the air changes of those rooms from about 2 air changes per hour to about 10+ air changes per hour.
    Be wary of sales gimmicks & concentrate on facts & installation details.
    From the many I have installed, I have encountered issues that along with manufacturer technical guidance, improvements have been greatly achieved. There are many concerns with ALL these various units, but as long as you are able to make an informed decision, you will not have any regrets. Installation detail is key.


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    #9
    gomamochi1
    Registered Users Posts: 542 ✭✭✭gomamochi1


    shane 007 wrote: »
    I have an oil condensing boiler with heat pump for dhw only. Works a treat & very inexpensive to run.
    House is 3,000sqft with UFH on both floors & costing approx €810 per year to heat.
    Heat pump for hot water is costing approx 34 cent per day.
    Very happy with both systems.
    Sorry for bumping into the thread but that sounds exactly what I am after. We are hoping to retrofit an existing 2400 foot dormer with ufh downstairs and upstairs. Is this a nightmare and not worth the hassle or am I better off sticking with the rads in sitiu? Also could you recommend by pm please the heat pumpnyou used and sys set up please? Really keen to go this way but de oh not too keen! Thanks a lot!


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    #10
    shane 007
    Closed Accounts Posts: 914 ✭✭✭shane 007


    gomamochi1 wrote: »
    Sorry for bumping into the thread but that sounds exactly what I am after. We are hoping to retrofit an existing 2400 foot dormer with ufh downstairs and upstairs. Is this a nightmare and not worth the hassle or am I better off sticking with the rads in sitiu? Also could you recommend by pm please the heat pumpnyou used and sys set up please? Really keen to go this way but de oh not too keen! Thanks a lot!

    PM sent.

    Retrofitting UFH will be no easy task & prove very costly to do correctly. Depending on your set up, I would most likely stick with radiators but increase the controls for it. If you are gutting your home, increase the number of time & temperature controlled zones to as many as you can. Each zone can be done via programmable room stats with one central touch screen controller that can alter each individual controller. Actuator manifold system for each room/zone.
    This would be cheaper than retrofitting UFH but still with superior controls.
    I would consider something like Firebird's Heat Box to limit short cycling of the boiler when low number of circuits are calling for heat. That is if you are sticking with an oil boiler.

    I am assuming you will be including high level upgrading of your existing insulation levels & air tightness.


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    #11
    gomamochi1
    Registered Users Posts: 542 ✭✭✭gomamochi1


    shane 007 wrote: »
    PM sent.

    Retrofitting UFH will be no easy task & prove very costly to do correctly. Depending on your set up, I would most likely stick with radiators but increase the controls for it. If you are gutting your home, increase the number of time & temperature controlled zones to as many as you can. Each zone can be done via programmable room stats with one central touch screen controller that can alter each individual controller. Actuator manifold system for each room/zone.
    This would be cheaper than retrofitting UFH but still with superior controls.
    I would consider something like Firebird's Heat Box to limit short cycling of the boiler when low number of circuits are calling for heat. That is if you are sticking with an oil boiler.

    I am assuming you will be including high level upgrading of your existing insulation levels & air tightness.

    Thanks for the reply. I take the point tat the added cost ain't worth it retrofitting ufh and it may come to that. Defo pumping walls and drylining to achieve airtighness the best option.
    I will check out those heat pumps to for the dhw too! Thanks


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    #12
    shane 007
    Closed Accounts Posts: 914 ✭✭✭shane 007


    gomamochi1 wrote: »
    Thanks for the reply. I take the point tat the added cost ain't worth it retrofitting ufh and it may come to that. Defo pumping walls and drylining to achieve airtighness the best option.
    I will check out those heat pumps to for the dhw too! Thanks

    I had my walls done with Walltite which pumps the cavities with an expandable closed cell liquid. It does both insulation & air tightness. I used a company in Meath. Found it made a huge difference also.


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    #13
    oconnb3
    Registered Users Posts: 13 ✭oconnb3


    hi lads in the same situation, 2000ft dormer 14 years old built it myself no thought given to airtightness or insulation. had a energy heat loss surey done recently because thinking of retrofit. Air blow test 7.5 leaks everywhere up stairs and around windows reveals and corners downstairs. thinking of putting Walltite in the cavity! what is the cost per sqm? are you happy with it?. secondly to take the upstairs apart as much as we can and putting in airtight membrane (walls floors crawl space and ceiling),adding more insulation to crawl space and attic. third putting in MVHC for ventilation....what would a system cost? and any recommendations for supply/install


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    #14
    shane 007
    Closed Accounts Posts: 914 ✭✭✭shane 007


    For me, Walltite is excellent. I am very happy with it. The combination of air tightness & added insulation is the enormous benefit.
    Where both my daughter's bedrooms are north facing, I could never get the room temps above 17C, no matter how long the heating was on for. Now they are a constant 20 - 21C.
    Cost wise, it's dear, €25 + vat per m2. Obviously deduct doors & windows from wall areas.
    It seems to worth out at approx 2.5 times more expensive than bonded beads but I would say 10 times better.
    My view is you can only fill your cavity once, so you have only one opportunity to get it right.
    You will need a vent in every room afterwards. I already had them. Also be prepared for cutting snots of it off everywhere, around windows, doors , tiny cracks, etc. it seals everything.


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    #15
    gomamochi1
    Registered Users Posts: 542 ✭✭✭gomamochi1


    shane 007 wrote: »
    I had my walls done with Walltite which pumps the cavities with an expandable closed cell liquid. It does both insulation & air tightness. I used a company in Meath. Found it made a huge difference also.
    Could you pm me please re name of the co in Meath that pumped the walls? Thanks


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    #16
    shane 007
    Closed Accounts Posts: 914 ✭✭✭shane 007


    gomamochi1 wrote: »
    Could you pm me please re name of the co in Meath that pumped the walls? Thanks

    Sure


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    #17
    oconnb3
    Registered Users Posts: 13 ✭oconnb3


    thanks for that, better get it right this time.....Any infro on Mech Ventilation Heat Recovery or Demand Control Ventilation trying to work out which suits retrofit better as we are trying to achieve a good air tightness


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    #18
    Man of Aran
    Registered Users Posts: 237 ✭✭Man of Aran


    shane 007 wrote: »
    Sure

    Hi Shane, appreciate if you can pm the name of Walltite contractor you used to me also. TIA.


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