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Heat recovery recommendations

  • #1
    Registered Users Posts: 294 ✭✭ cwboy


    Timber frame is standing now and need to make a decision on a heat recovery system. Can anybody pm me details of a comany they have used and are happy with. So many places now offering them but i would prefer to hear from people who have them in and working well.

    Thanks


«1

Comments



  • What part of country are ya in?




  • I am in exactly the same position as cwboy (timber frame up and planning on installing HRV too), so would appreciate if you could pass any recommendations my way too. I'm based on Cork.

    I've been quoted around €6k for supply and installation (275 sqm house). Because I am not 100% convinced by the supplier, plus because I feel that it's not rocket science to install it, I'm thinking I could save a lot by having it installed myself. So I'm thinking possibly of going the DIY route (or at least buying the unit and ducting etc. and installing with the help of some tradesmen already on site). But I'd welcome any thoughts people may have on this.

    I've seen this really cheap unit (hope this link below works) - does anyone have any thoughts on whether I'd be taking a big gamble by going with something like this or any suggestions as to where I could get a decent unit for DIY installation.

    http://cgi.ebay.co.uk/WHOLE-HOUSE-VENTILATION-HEAT-RECOVERY-EXTRACTOR-FANS_W0QQitemZ380044987054QQcmdZViewItem?_trksid=p3286.m20.l1116

    Finally, wonder if any of you would have any thoughts on the following..? One supplier has told me that, because of the shape of my house (L shaped), I would need two separate HRV units for the two parts of the house because the duct lengths would be too long if I were to go with just one unit (although another supplier quoted me for one unit and didn't raise any concern on that score). Having two units, would obviously add to the cost (which is why the cheap unit referred to above is especially attractive!) But another concern would be where would I be extracting the warm/moist air from that's meant to heat the fresh air coming in. It's not a problem on the side of the house where the kitchen/utility is located. But on the other side, there's one bathroom that will get some use, though not a lot (and obviously no kitchen). On that side of the house, there is a sitting room that will have a wood burner, but any schematics I have seen always show the air being extracted from "moist" rooms (kitchens/bathrooms) and not from other rooms. I would have thought that there would be some benefit to extracting air from a room with a stove, thereby warming the air entering other rooms or is that the wrong way to think about what a HRV system is doing?








  • With all due respect I think the list from the SAP is pretty small and UK-centric.
    I think we should be looking at countries other than the UK for best building practices.
    The UK is not exactly at the cutting edge of efficient house design:)




  • can you post a usefull link CJ ?


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  • The OP asked for advice and feedback on HRV systems from people have installed and used MHRV systems.
    I am not about to start posting the manufacturers website but have PM'd the two posters that asked for information and advice.
    I have a Temovex 480 system in since 2005 and it is working well, with very low noise levels, good ventilation, low humidity <50%.
    The filters are easy to change because the unit is on the ground floor not in an attic.
    No problems with resonant noise through joists and frames.
    Large mufflers.
    Galvanised steel spiral wrap ducting sized correctly for flow.200mm/150mm/100mm depending on room size/use
    All ducting lagged with fibreglass, horrible job but essential for efficiency.
    I fitted mine in two days with a mate, not rocket science but take your time and think about what you are doing.
    There is my 2c
    The manufacturer sells a lot of these in Sweden where MHRV is standard in most homes, rather than an oddity.
    Thanks for the links, have you got MHRV yourself?




  • No CJ I don't . Pleased that you are happy with your installation




  • CJhaughey wrote: »
    With all due respect I think the list from the SAP is pretty small and UK-centric.
    I think we should be looking at countries other than the UK for best building practices.
    The UK is not exactly at the cutting edge of efficient house design:)

    No real argument there CJ - the list is UK dominated , but there is a German Finish and Irish supplier on the list .

    Problem is - when it comes to BER assessment time - if a product is not on Appendix Q ( which DEAP manual tells us to consult ) - the assessor has no discretion but to enter a DEAP default for the efficiency value . The default value is 0.66 .

    So i would be careful about straying from the appendix Q list .




  • Wow, correct me if I am wrong but does that mean that the BER programme in Ireland has instructed its assessors to use limited data from a UK testing company as part of the BER here?
    If so the BER is an even more worthless piece of paper than I originally thought.
    :rolleyes:
    The very fact that the BER is based on Projected values rather than real tested values is a worrying factor IMO.
    I wonder if there is a EU testing agency that has a more comprehensive results list?




  • CJhaughey wrote: »
    Wow, correct me if I am wrong but does that mean that the BER programme in Ireland has instructed its assessors to use limited data from a UK testing company as part of the BER here?
    If so the BER is an even more worthless piece of paper than I originally thought.
    :rolleyes:
    The very fact that the BER is based on Projected values rather than real tested values is a worrying factor IMO.
    I wonder if there is a EU testing agency that has a more comprehensive results list?

    your not wrong - appendix q or default efficiency 0.66 - for now

    http://www.sei.ie/index.asp?locID=1011&docID=-1

    BER system is not perfect - for sure . I have posted many reservations before

    But real tested values do play a part eg

    - if an air tightness test has been carried out - you enter that result
    - appendix q , even if UK dominated , is based on tested performance values
    - windows u values must be demonstrated by test results -otherwise a conservative default must be used
    - solar panels tested performance data can be entered

    EU testing agency for HRV ? - good question , don't know , let us know if you locate one


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  • hey CJ

    how much insulation did you put around the pipes. I have very little space in my roof raters and worried the how mush this will affect the efficiency ???




  • Holdfast
    From memory I used 100mm fibreglass cut into sheets and wrapped around the pipework.
    When we did it, one lucky person held the wrap and the other (me) used a length of twine to half hitch around the pipe on a continuous basis.
    The pipework that ran with the joists was already laid on a bed of insulation and I just laid more on top under the flooring.




  • Thanks for the info. I have been told that as the house is a dormer bungalow it will be very hard to get airtight with so many ins and outs. Was told that the house will be easy heat being well insulated with a boiler stove and solar panels with oil backup. Therefore not much point spending six/seven grand on the heat recovery system. I was convinced before but not so much now if it will be hard to get airtight. Based in carlow to answer previous question




  • Cwboy, if you don't have HRV you will have to ventilate the rooms in your house with the "hole in the wall" method.
    This in turn will create draughts and cold rooms and is generally an inefficient way to ventilate a house.
    HRV is one of the most important factors in having a dry and well ventilated environment inside a house.
    I would make the effort to try and make the house as airtight as possible, it's worth it in the long run.
    Easy to heat doesn't necessarily mean easy to keep hot.




  • Thanks CJ

    The contractor put the pipes in the rafter close to the felt not much room to wrap around and this was after I told him when I was pricing. Anyway I am going to put as much around as I can. Thanks Again.

    Know tot he nightmare of trying to get airtight around the pipes as the run throught a unheated space.




  • cwboy wrote: »
    Thanks for the info. I have been told that as the house is a dormer bungalow it will be very hard to get airtight with so many ins and outs. Was told that the house will be easy heat being well insulated with a boiler stove and solar panels with oil backup. Therefore not much point spending six/seven grand on the heat recovery system. I was convinced before but not so much now if it will be hard to get airtight. Based in carlow to answer previous question

    Bad advice there cwboy . Dormers are tricky to make air tight - but it can be done - and it is very important that it is done . There is every point in HRV - you will spend more and more €'s on heat energy as time progresses - so recovering it will make more and more sense in to the future .




  • i dont have any membrane in my house at the moment. just basic timberframe shell. How would i make this airtight? Do i make it airtight across downstairs ceiling and around sides and let heat up the stairs void then continue airtightness around upstairs? i cant see now how i get membrane to go down the sides of the house form top to bottom i.e. no membrane where floor meets the walls to tie in to. i would in effect try to make two zones upsrairs and downstairs with break in middle for stairs. not afraid of putting in the hours to get it airtight but not sure how to go about it. any help greatly appreciated




  • hello all,

    thanks to cj for the private message, and sinnerboy if you still need contacts let me know,

    i have built the structure at this point, its a storey and a half, standard cavity with 60 mm kingspan, am going to dry line all exterior walls with insulated board, im going for hrv too with two stoves, so no open fires,

    Can anyone give some tips on improving air tightness?

    thanks all,




  • I used the green ageproof plastic that was supplied with my house.
    What I did was hang the sheet up and staple it from the highest point then smoothed it out and stapled it down the individual frame members.
    Leave an overlap so that it can be taped with the special green tape (very flexible) and joined to the next sheet.
    My house was simple because it is a rectangular shape no dormers etc.
    But it can be done if you take your time.
    Then just slab on top of the membrane.




  • cwboy wrote: »
    any help greatly appreciated

    look at pm i sent you a few days ago


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  • gally74 wrote: »
    hello all,


    Can anyone give some tips on improving air tightness?

    thanks all,

    http://www.planningportal.gov.uk/uploads/br/masonry_internal_wall_insulation_illustrations.pdf




  • cwboy wrote: »
    How would i make this airtight? Do i make it airtight across downstairs ceiling and around sides and let heat up the stairs void then continue airtightness around upstairs?

    look at 3rd link in post 4 in this thread




  • sinnerboy thanks for that.

    my problem is that i do not have the air barrier behind the junctions where the walls and first floor meets the external walls.




  • cwboy wrote: »
    sinnerboy thanks for that.

    my problem is that i do not have the air barrier behind the junctions where the walls and first floor meets the external walls.

    call any of the people i pm'd you . they will visit site and advise "on the ground"




  • thanks for your help. sorry if they were stupid questions. will call those people tomorrow




  • no problem - your questions were pertinenent -not stupid

    keep in touch :)




  • Rang those guys in Wexford. Told me it would take a lot of work to get it airtight but it was possible. Is the green vapour barrier supplied with the house OK to use as the airtight barrier or should i get the "proper" stuff




  • If you mean the breather membrane attached to the outside of the frame - no .

    The air tight barrier must be at or close to the internal wall face .

    You can deem your plasterboard to be your air tight barrier - the practical implication then is that you must look at every single place where it is penetrated and / or joined at make sure you seal it well . (3rd url post no 4 refers)

    The "proper stuff" is available in Ireland in 2 guises only - Intello and Siga . These membranes are variable-permeable . In winter they "close up" and stop warm air from migrating out . In summer they open up and allow the timber frame to "breath" into the internal spaces

    Now if you line your internal frame with "proper stuff" and then affix a grid of 50 x 50 battens over to create a services cavity - now the "proper stuff" acts as an excellent air tight barrier and because you don't allow pipes and cables to penetrate it - you eliminate a lot ( not all ) of you air tightness hassles

    http://constructireland.ie/ - get hold of the July / Aug issue - there is good article on timber framed housing in Fingal which expands on this

    You spoke of HRV . with timber frame , if you don't use "proper stuff" but rely instead on the plasterboard face - you are very , very , very unlikely to get down to a suitable level of air tightness

    .




  • thanks again for very helpful post.

    sorry i was unclear. I meant the green plastic supplied to act as the vapour barrier on the warm side of the insulation.


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  • cwboy wrote: »
    thanks again for very helpful post.

    sorry i was unclear. I meant the green plastic supplied to act as the vapour barrier on the warm side of the insulation.

    this is ok If it can be maintained intact - i.e. sealed to all services penetrations and sealed - to window frames - to floor slab - around upper floor - and to be sealed at wall plate and to extend upwards along roof timbers

    A services wall cavity would give you a better chance of success . So would calling the royal county folk ;)


    .


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