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Ventilation alternative

  • 07-03-2014 5:36pm
    #1
    newgroom
    Registered Users, Registered Users 2 Posts: 13 ✭


    Hi all, I am currently building a new house and I made a decision early in the build not to install MHRV as it was expensive and a hole in the wall is obviously a little cheaper and I think more than adequate. I felt that the payback in relation to savings on your heating bill v the cost of the MHRV wasn't selling me on it.

    Now I'm coming to the end of the build I have been searching for wall vents covers to fit in the rooms. I have seen some vent covers on the market such as the axia-vent range but I was wondering if there any natural (not mechanical) wall vents on the market that will not cause significant temperature losses in the room or leave a icey cold blast in the harsh dec/jan/feb months? And since i've to buy 8 units i don't want to break the bank either.

    Your advice is much appreciated.


Comments

  • #2
    fclauson
    Registered Users, Registered Users 2 Posts: 1,691 ✭✭✭fclauson


    newgroom wrote: »
    Hi all, I am currently building a new house and I made a decision early in the build not to install MHRV as it was expensive and a hole in the wall is obviously a little cheaper and I think more than adequate. I felt that the payback in relation to savings on your heating bill v the cost of the MHRV wasn't selling me on it.

    Now I'm coming to the end of the build I have been searching for wall vents covers to fit in the rooms. I have seen some vent covers on the market such as the axia-vent range but I was wondering if there any natural (not mechanical) wall vents on the market that will not cause significant temperature losses in the room or leave a icey cold blast in the harsh dec/jan/feb months? And since i've to buy 8 units i don't want to break the bank either.

    Your advice is much appreciated.

    Are you building to Part L 2011 or 2008 ? You will find it very hard to achieve compliance without an MHRV.

    Otherwise read Part F for ventilation requirements - you will need a 6inch unobstructed hole in most rooms. There are devices to limit draft while keeping the required free flow space on the market.

    You could also look at demand vents and a central extract unit - these demand vents open and close themselves


  • #3
    galwaytt
    Registered Users, Registered Users 2 Posts: 12,823 ✭✭✭✭galwaytt


    newgroom wrote: »
    Hi all, I am currently building a new house and I made a decision early in the build not to install MHRV as it was expensive and a hole in the wall is obviously a little cheaper and I think more than adequate. I felt that the payback in relation to savings on your heating bill v the cost of the MHRV wasn't selling me on it.

    Now I'm coming to the end of the build I have been searching for wall vents covers to fit in the rooms. I have seen some vent covers on the market such as the axia-vent range but I was wondering if there any natural (not mechanical) wall vents on the market that will not cause significant temperature losses in the room or leave a icey cold blast in the harsh dec/jan/feb months? And since i've to buy 8 units i don't want to break the bank either.

    Your advice is much appreciated.

    Tbh this is something that should have been done at design stage - is a bit late to try and invent a solution now.

    MHRV is about de facto these days- and the buildngs with it are measurably better. "Adequate" as you describe actually....isn't.

    I'm not aware of anything other than a conventional open vent at this stage, which is a pity.

    Ode To The Motorist

    “And my existence, while grotesque and incomprehensible to you, generates funds to the exchequer. You don't want to acknowledge that as truth because, deep down in places you don't talk about at the Green Party, you want me on that road, you need me on that road. We use words like freedom, enjoyment, sport and community. We use these words as the backbone of a life spent instilling those values in our families and loved ones. You use them as a punch line. I have neither the time nor the inclination to explain myself to a man who rises and sleeps under the tax revenue and the very freedom to spend it that I provide, and then questions the manner in which I provide it. I would rather you just said "thank you" and went on your way. Otherwise I suggest you pick up a bus pass and get the ********* ********* off the road” 



  • #4
    baby fish
    Registered Users, Registered Users 2 Posts: 268 ✭✭baby fish


    The air inlet vents you might be thinking of are the Aereco EHT, Passivent Fresh 99 H and maybe the Lunos ALD R 160, the first two are humidity sensitive, the third can be set in one of three position which will set the max airflow at a certain level.

    They are not cheap with a price of between 50 e and 150e ex vat.

    These vents are designed for use as part of a demand control ventilation system ( DCV). you could check with manufacturer as to their suitability for use in a naturally ventilated house. I suspect They will work but there is a problem as they are not really designed for natural/trickle ventilation.

    The problem is you will need to install a lot of them to ventilate a house naturally and comply with building regs, this is due to their low EA

    The equivalent area (EA) of aereco inlet is about 4000mm Sq, the EA of passivent is about 3500 so 8 vents will not be enough to ventilate you house properly.

    Read pg12Irish TGD F you can work out how much ventilation you require for your house.

    Rough example is house of about 130 SQm with air permability > 5 will need 15 vents that have an EA of 4000 mm SQ and the same house with an air permability of <5 will need 21 air inlets that have an EA of 4000mm SQ

    That's a lot of vents:eek: , you'd nearly be better off putting in a proper DCV system and then your 8 vents should be enough then.

    I installed MHRV in my house but if I was back again I wouldn't. MHRV has its fans but I'm no longer one of them :mad: .....thats a post for another day.


    Good luck :)


  • #5
    hexosan
    Registered Users, Registered Users 2 Posts: 1,740 ✭✭✭hexosan


    Why are you no longer a fan ??


  • #6
    galwaytt
    Registered Users, Registered Users 2 Posts: 12,823 ✭✭✭✭galwaytt


    hexosan wrote: »
    Why are you no longer a fan ??

    sorry for the OT, but 'fan' and mhrv - ironic :P

    Tbf, my SO isn't a fan, either. Or wasn't. Like my plumbing, getting it commissioned properly after first fix was the big thing. Pragmatically, I can't see how my house could even function without it: if you turn it off, air quality measurably deteriorates.

    Ode To The Motorist

    “And my existence, while grotesque and incomprehensible to you, generates funds to the exchequer. You don't want to acknowledge that as truth because, deep down in places you don't talk about at the Green Party, you want me on that road, you need me on that road. We use words like freedom, enjoyment, sport and community. We use these words as the backbone of a life spent instilling those values in our families and loved ones. You use them as a punch line. I have neither the time nor the inclination to explain myself to a man who rises and sleeps under the tax revenue and the very freedom to spend it that I provide, and then questions the manner in which I provide it. I would rather you just said "thank you" and went on your way. Otherwise I suggest you pick up a bus pass and get the ********* ********* off the road” 



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  • #7
    newgroom
    Registered Users, Registered Users 2 Posts: 13 ✭newgroom


    Thanks baby fish, some very useful information there. You are correct I will need more vents to comply, I've accepted that now.
    You can comply with Building Regs by natural ventilation but it isn't easy and vent opes do have to be sizable. I work in the Building Control industry and am very aware of Part F and Part L. I personally don't notice the difference in "air quality" in non-MHRV houses compared to MHRV houses but that's me. The biggest issue i personally have is a breeze through natural vents which is why i posted this for advice. I was getting quotes of over €6000 to fit one in my house plus filter changes and electrical costs. Plus it's just another machine or system in my house that needs service/maintenance and can go wrong. My personal option is that MHRV is great and works but it's a luxury in some domestic houses that not everybody needs/want. I don't see why natural ventilation is not adequate if fitted compliant with the building regs?


  • #8
    fclauson
    Registered Users, Registered Users 2 Posts: 1,691 ✭✭✭fclauson


    newgroom wrote: »
    ... I don't see why natural ventilation is not adequate if fitted compliant with the building regs?

    Simply put - heat loss :eek:


  • #9
    MicktheMan
    Registered Users, Registered Users 2 Posts: 2,880 ✭✭✭MicktheMan


    newgroom wrote: »
    I don't see why natural ventilation is not adequate if fitted compliant with the building regs?

    There is an interesting article in the latest Passive House Plus edition which does not concur with this statement.


  • #10
    MicktheMan
    Registered Users, Registered Users 2 Posts: 2,880 ✭✭✭MicktheMan


    newgroom wrote: »
    My personal option is that MHRV is great and works but it's a luxury in some domestic houses that not everybody needs/want.

    The same can be said for a fridge.:)


  • #11
    baby fish
    Registered Users, Registered Users 2 Posts: 268 ✭✭baby fish


    hexosan wrote: »
    Why are you no longer a fan ??

    Many reasons, in short I'm not happy with equipment, the installation, I'm not convinced the quality of filtered air is as good as fresh air, I'm not convinced there is a min standard for MHRV installations to comply with......Yes they are building regs but really all these are concerned about is getting X amount of air into the house and X amount of air out of the house. It doesn't really care how you do it or what happens as a result of doing it...just get the air in and out,

    Example of complying with regs and getting something you don't want in return is when a homeowner puts in the required # hole in the wall vents, you will get the required ventilation... building regs are satisfied, great! but along with satisfying the regs comes a house that is harder to heat.

    This is a problem for some people that MUST be avoided at all costs.
    Lets install an alternative..

    MHRV, no doubt you will get the required ventilation 24/7... building regs are satisfied , Fantastic.... or is it?do we really know what we are getting???? ... I've had a good look over my entire system and I'm not that convinced this is the way forward for a healthy indoor air quality.

    Here's An example of a building reg that doesn't work , install a min of 25mm of insulation around ducting. its not enough, I've looked in my extract ducts and there is mould in them.

    I see regs that are not good enough and I see equipment that can only be described as junk , but it is still acceptable and is considered the best way to ventilate a house at the moment.

    If a person wants to live in a house that is warmer, quieter (outside noises wind etc) ,has filtered air and you trust there are standards in place to ensure it does what it claims to do then go for MHRV.

    I'd rather live in house that is a little harder to heat ( but not impossible)and has fresh(not filtered) air.


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  • #12
    sydthebeat
    Subscribers Posts: 42,172 ✭✭✭✭sydthebeat


    baby fish wrote: »

    I'd rather live in house that is a little harder to heat ( but not impossible)and has fresh(not filtered) air.

    perhaps a read of the latest edition of passive house + where there's an article which suggests 'hole in the wall' vents may not work sufficiently at all


  • #13
    galwaytt
    Registered Users, Registered Users 2 Posts: 12,823 ✭✭✭✭galwaytt


    baby fish wrote: »
    Many reasons, in short I'm not happy with equipment, the installation, I'm not convinced the quality of filtered air is as good as fresh air, I'm not convinced there is a min standard for MHRV installations to comply with......Yes they are building regs but really all these are concerned about is getting X amount of air into the house and X amount of air out of the house. It doesn't really care how you do it or what happens as a result of doing it...just get the air in and out,

    Example of complying with regs and getting something you don't want in return is when a homeowner puts in the required # hole in the wall vents, you will get the required ventilation... building regs are satisfied, great! but along with satisfying the regs comes a house that is harder to heat.

    This is a problem for some people that MUST be avoided at all costs.
    Lets install an alternative..

    MHRV, no doubt you will get the required ventilation 24/7... building regs are satisfied , Fantastic.... or is it?do we really know what we are getting???? ... I've had a good look over my entire system and I'm not that convinced this is the way forward for a healthy indoor air quality.

    Here's An example of a building reg that doesn't work , install a min of 25mm of insulation around ducting. its not enough, I've looked in my extract ducts and there is mould in them.

    I see regs that are not good enough and I see equipment that can only be described as junk , but it is still acceptable and is considered the best way to ventilate a house at the moment.

    If a person wants to live in a house that is warmer, quieter (outside noises wind etc) ,has filtered air and you trust there are standards in place to ensure it does what it claims to do then go for MHRV.

    I'd rather live in house that is a little harder to heat ( but not impossible)and has fresh(not filtered) air.

    I see where you're coming from. The story on u-values is similar. People chasing down the rabbit hole and focussing on u-values, and then having poor airtightness. U-value you can have on paper...........airtightness is the measure of your quality-of-build. Which is where you last comment comes in........

    I think the biggest issue is not MHRV per se, but the ad-hoc nature of it's installation you've experienced. And it is true that the quality of building fabric has a huge amount to do with it (e.g. placing ducting in areas where it is condensing. That's not the MHRV unit's fault, or the piping's fault. That's the fault of the numpties who put it in that location). I work for a company that, outside of construction products, has been building products for the refrigeration business for 30+ years, and issues of ducting and compressor siting are Old News in that industry. Why construction can't rob a few pages from that book escapes me, tbh.

    I think you're possibly over-estimating the 'quality' of air in an un-MHRV house and under-estimating the 'quality' of air in an MHRV house (done well, that is).

    Ode To The Motorist

    “And my existence, while grotesque and incomprehensible to you, generates funds to the exchequer. You don't want to acknowledge that as truth because, deep down in places you don't talk about at the Green Party, you want me on that road, you need me on that road. We use words like freedom, enjoyment, sport and community. We use these words as the backbone of a life spent instilling those values in our families and loved ones. You use them as a punch line. I have neither the time nor the inclination to explain myself to a man who rises and sleeps under the tax revenue and the very freedom to spend it that I provide, and then questions the manner in which I provide it. I would rather you just said "thank you" and went on your way. Otherwise I suggest you pick up a bus pass and get the ********* ********* off the road” 



  • #14
    newgroom
    Registered Users, Registered Users 2 Posts: 13 ✭newgroom


    MicktheMan wrote: »
    The same can be said for a fridge.:)

    A fridge is essential, MHRV isn't


  • #15
    fclauson
    Registered Users, Registered Users 2 Posts: 1,691 ✭✭✭fclauson


    newgroom wrote: »
    A fridge is essential, MHRV isn't

    No - would not put my milk into an MHRV in the same way I would not allow my fridge to ventilate my house


  • #16
    MicktheMan
    Registered Users, Registered Users 2 Posts: 2,880 ✭✭✭MicktheMan


    newgroom wrote: »
    A fridge is essential, MHRV isn't

    Nope


    Food preservation is essential as is ventilation.

    A fridge is an efficient method of food preservation (but there are other less efficient methods) just as a mvhr system is an efficient method of providing ventilation (but there are other less efficient methods here also).


  • #17
    baby fish
    Registered Users, Registered Users 2 Posts: 268 ✭✭baby fish


    sydthebeat wrote: »
    perhaps a read of the latest edition of passive house + where there's an article which suggests 'hole in the wall' vents may not work sufficiently at all

    I wouldn't expect to find an article in passive house plus that suggests a hole in the wall vent actually works, that's not what they are interested in advertising.

    Passive house plus doesn't know the orientation of my house, its foot print, if its a wide or narrow plan , the floor plans, position of doors , wall areas available to position vents for cross ventilation etc. So how can they say hole in the wall vents may not work sufficiently, every house is different.

    But looking at it again, they state it "may not work" , so its fair to say it might work too.

    like all people in favour of MHRV will say, you need to plan in advance for MHRV to work properly, but you will also need to plan in advance the location of a hole in the wall vent for it work to the best of its ability while minimising unwanted draughts.

    (by the way, like the OP I am now looking for an alternative to MHRV, I'm hoping to use humidity sensitive air inlets to ventilate my house and if this doesn't provide sufficient ventilation I will introduce a DCV extractor fan)


    But I know where you are coming Syd, I've no problem agreeing that hole in the wall vents will be no where near as effective/efficient as MHRV, but that doesn't bother me, I'm happy to live with that. saving a few hundred euro on oil is not so important for me anymore and not having a constant flow of air through the house 24/7 X 365, I can live without this too if ventilation is sufficient through a wall inlet, using humidity sensitive inlets will make things a bit more comfortable.
    galwaytt wrote:
    I think the biggest issue is not MHRV per se, but the ad-hoc nature of it's installation you've experienced

    Right now I'd share my disappointment equally between the MHRV unit and the ducting. I Agree with what you are saying re installation ,but this happens in the majority of houses in Ireland with MHRV. We are not all building a passive house where MHRV is considered from the start. There are many houses not suitable for MHRV, or a better way of saying this is MHRV hasn't been considered until the end which is too late , yet ask the supplier/installer after building work has commenced re suitability of Mhrv - oh yes MHRV will be perfect in your house. Anyway, if I had planned it from the start I would still have a poor installation, that I'm sure of.

    So the poor layout/workmanship that went into my ducting isn't my only reason for seeking an alternative to MHRV, the MHRV unit itself is a piece of junk that is listed on SAP appendix Q, people seem to think ( well I did anyway) if its listed here it must be good. Not true.

    This is an important question , to what standards are these MHRV air handling units made? can anyone answer this?

    from what I can see there are no standards.

    I asked the manufacturer to prove to me with test results the air is clean and filtered (they state something like this in their advertisement)....no evidence available, prove the air quality is better in my house with MHRV installed.... they cant. seems the only thing people are interested in and they can prove is how efficient the units are.


    galwaytt wrote:
    That's the fault of the numpties who put it in that location)

    Don't get me started :mad:. Things could have been better, but as I have mentioned earleir, the air handling unit is a piece of junk, the numpties didnt design/make/test/manufacture this air handling unit.

    just in case it was missed above, Ill ask again: Does Anybody know to what standards are the MHRV air handling units made?
    galwaytt wrote:
    and issues of ducting and compressor siting are Old News in that industry. Why construction can't rob a few pages from that book escapes me, tbh.

    Agree with you 100% . there should be Nothing new here for mhrv, but from what I can see there are No decent regs, guidelines or standards - so substandard work and materials is common
    galwaytt wrote:
    I think you're possibly over-estimating the 'quality' of air in an un-MHRV house and under-estimating the 'quality' of air in an MHRV house (done well, that is).

    I think that the fresh air that comes through a hole in the wall vent is better than filtered air through an MHRV unit. What exactly am I hoping to filter out? I don't walk around outside with a mask on, why would I want to filter the air coming into my house. At the end of the day really the filters are there to protect the fans so this is false advertisement

    But if you are saying that the ventilation is better with MHRV ? Maybe it is but I think with Proper positioning of hole in the wall vents and other things like using extractor fans+ plus avoiding drying clothes in house, air quality will be perfect in a house without MHRV, having looked in my ducts:eek:, I'd say its better!


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