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No heatpump, HRV or underfloor on a new build

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  • 30-10-2015 11:17am
    #1
    ArraMusha
    Registered Users Posts: 589 ✭✭✭


    I'm at the construction drawing phase of a new build and before I sit down with my Engineer I would appreciate any feedback on the below item.

    I'd prefer not to install a heat pump and would like to stick to the older reliables of oil, radiators and a wood burning stove. I realize that part L of the building regulations make it mandatory to install renewable forms of heating, like solar or photovoltaics, but if the insulation is to a very high spec over the complete envelope how can I find out at this stage what are my options for renewables, with this setup?
    The house is 208 sqm., Windows to A3, 150mm floor insulation, 250mm cavity.

    Also, if I don't install an airtight membrane and don't seal the windows,doors etc. and don't install a HRV system, besides air tightness and air exchanges per hour are there any other compliance issues that need to be considered?

    It is well documented that HRV systems provide clean warm air and reduce energy loss and are of benefit to asthmatics.
    The two issues I have with HRV are 1)Most of the work they do (cleaning and warming inhaled air) should be done by the nose and respiratory system. 2) The can cost anything form 4-6k.

    Thanks for reading and posting comments.:)


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    #2
    893bet
    Registered Users Posts: 8,830 ✭✭✭893bet


    Get a prelim BER done. It will tell you what u need renewables wise.

    Airtightness and some kind of mechanical ventilation is a must. Not even sure if regs can be meet with hole in the wall vents.


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    #3
    ArraMusha
    Registered Users Posts: 589 ✭✭✭ArraMusha


    Thanks 893bet. I'll get the theoretical BER done to see what renewables are needed.

    There is a mechanical type vent (no fan) that I heard about which allows high winds to be blocked and disperses air over the surface of the walls. Not sure who the manufacturers are or the customer satisfaction with these?


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    #4
    sydthebeat
    Subscribers Posts: 41,253 ✭✭✭✭sydthebeat


    ArraMusha wrote: »
    I'm at the construction drawing phase of a new build and before I sit down with my Engineer I would appreciate any feedback on the below item.

    1. I'd prefer not to install a heat pump and would like to stick to the older reliables of oil, radiators and a wood burning stove. I realize that part L of the building regulations make it mandatory to install renewable forms of heating, like solar or photovoltaics, but if the insulation is to a very high spec over the complete envelope how can I find out at this stage what are my options for renewables, with this setup?
    The house is 208 sqm., Windows to A3, 150mm floor insulation, 250mm cavity.

    2. Also, if I don't install an airtight membrane and don't seal the windows,doors etc. and don't install a HRV system, besides air tightness and air exchanges per hour are there any other compliance issues that need to be considered?

    3. It is well documented that HRV systems provide clean warm air and reduce energy loss and are of benefit to asthmatics.
    The two issues I have with HRV are 1)Most of the work they do (cleaning and warming inhaled air) should be done by the nose and respiratory system. 2) The can cost anything form 4-6k.

    Thanks for reading and posting comments.:)

    1. as above, the only way to know what specification you need to build is to get a preliminary BER (DEAP) assessment done. The minimum required insulation levels are already at a "high level"

    2. the problem here is that the lack of air tightness effects every other specification.... in that if you build a house to worst acceptable air tightness, you will have to upgrade all your other elenments to supplement this.. which means more solar required, higher insulations levels, better windows etc.

    3. as above, if you dont use a MHRV system, you must upgrade all other elements.


    this will all become very clear to you when you sit down with an assessor and see what knock on effects your choices make.


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    #5
    ArraMusha
    Registered Users Posts: 589 ✭✭✭ArraMusha


    Thanks 'sydthebeat' for your feedback ! :)


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    #6
    mfceiling
    Registered Users Posts: 12,791 ✭✭✭✭mfceiling


    Not bothering with airtightness is like buying a coat but only putting on one arm and not zipping it up.


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    #7
    ArraMusha
    Registered Users Posts: 589 ✭✭✭ArraMusha


    mfceiling wrote: »
    Not bothering with airtightness is like buying a coat but only putting on one arm and not zipping it up.

    I hear you 'mfceiling', and in keeping with you analogy the point I'm making is its ok and possibly healthier not to zipp up the coat, and to eat more instead.

    Long term living in a bubble (air tight house) is just something I'm not comfortable with, but I'm open to being convinced.


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    #8
    sydthebeat
    Subscribers Posts: 41,253 ✭✭✭✭sydthebeat


    ArraMusha wrote: »
    I hear you 'mfceiling', and in keeping with you analogy the point I'm making is its ok and possibly healthier not to zipp up the coat, and to eat more instead.

    Long term living in a bubble (air tight house) is just something I'm not comfortable with, but I'm open to being convinced.

    well taking the extreme example, they dont seem to have a problem with it in the international space station... and thats as 'air tight' as you can get ;)
    submarines as well are designed for exterem air tightness

    i think the perception that an 'airtight' house is a 'bubble' is an incorrect one.

    what we try to do is design out the 'uncontrolled' or 'unintended' air leakage from a building and leaving the controlled and designed air inflows.


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    #9
    Drift
    Closed Accounts Posts: 1,395 ✭✭✭Drift


    ArraMusha wrote: »
    Long term living in a bubble (air tight house) is just something I'm not comfortable with

    That's why you put mechanical ventilation inn the house - to ensure that it is a well ventilated bubble.

    Designed ventilation is targetted at the correct areas delivering appropriate volumes of fresh air to specific points and removing fouled/less healthy air from cooking areas, toilets, etc.

    Your approach is to hope that by doing a less tidy build the air leaking in and out of the building (which varies based on the prevailing weather conditions and the degree of how untidy you've been in your build) will provide appropriate healthy air supply to correct locations and remove poor air elsewhere. It might work - but more than likely it won't and you'll end up with dead pockets and draughty pockets.

    Why spend all that time designing a brilliant layout for your house and not put time into designing how to make it comfortable and healthy?


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    #10
    overshoot
    Registered Users Posts: 3,209 ✭✭✭overshoot


    ArraMusha wrote: »
    It is well documented that HRV systems provide clean warm air and reduce energy loss and are of benefit to asthmatics.
    The two issues I have with HRV are 1)Most of the work they do (cleaning and warming inhaled air) should be done by the nose and respiratory system.
    I think you misunderstand the best effects of HRV here, yes the extra air changes will remove slightly more dust from the air but it also removed a lot more carbon dioxide/monoxide etc and gets the most oxygen in the air you breathe.... short of a mutation your nose wont do that!
    Its not just warming the air for inhalation, think hands & feet. You said yourself you want oil, which costs money, presumably to heat your rooms/the air in them? Why let the heat seep out of the house? Its more efficient/cheaper in the long term to transfer it from one area to another than create it from scratch.

    With this type of build, it is only airtight where you cannot control the airflow. The rooms have a constant supply of fresh air (more than your old trickle vents) with the heat recycled from the escaping air rather than lost for good.


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    #11
    Metric Tensor
    Registered Users Posts: 3,724 ✭✭✭Metric Tensor


    I have found modern houses (i.e. last 5-10 years) that rely on trickle vents alone feel stuffy.

    I don't know is there any measured scientific data to back this up.


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    #12
    galwaytt
    Registered Users Posts: 12,761 ✭✭✭✭galwaytt


    ArraMusha wrote: »
    I hear you 'mfceiling', and in keeping with you analogy the point I'm making is its ok and possibly healthier not to zipp up the coat, and to eat more instead.

    Long term living in a bubble (air tight house) is just something I'm not comfortable with, but I'm open to being convinced.

    As syd says, an airtight house is not stuffy at all. This is a common misconception. Airtight is a reflection of quality of build, it is not a measure of/if the building is ventilated, nor how.

    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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    #13
    MightyMunster
    Registered Users Posts: 1,258 ✭✭✭MightyMunster


    Makes no sense not to go airtight with MHRV. Would have thought it's a no brained. Saving thousands in heating costs and more importantly a comfortable, dry house to live in. Having lived in many old, draughty, damp and cold houses/flats anyone that wants to go back to condensation on Windows, mould, etc is mad!


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    #14
    Falcon L
    Closed Accounts Posts: 891 ✭✭✭Falcon L


    Two and a half years ago we were building our new house. We knew what we wanted it to do for us and we were prepared to make a stand against the conventional beliefs that you see above.

    I know that MHRV delivers fresh air into the house, but it's not the same coming out of a vent in the ceiling as it is coming in through an open window. My wife and I have always been fresh air fiends and the windows are always open, day and night. This was always going to be a problem with an MHRV system. We weren't prepared to live with closed windows, period.

    What we ended up with is a very well insulated house, similar to what you describe in your OP. Oil heating that never gets used. We got 500L of oil delivered 2 years ago and most of it is still in the tank! The stove takes care of our heat needs and we have an endless supply of free logs.

    The water is heated by a stand-alone unit with a small air to water heat pump built into it. We have 270L of very hot water available all the time (even when we had 6 adults and 2 children staying with us for a couple of weeks) The cost for this hot water worked out at €105 (measured) for the year 2014. We are on course for a similar cost for 2015. We could add a solar collector to this system but the savings would never justify the cost.

    We may not conform to the gospel, but we scraped an A3 BER. We've never felt uncomfortable in the house and stuffy it aint. :cool:


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    #15
    Metric Tensor
    Registered Users Posts: 3,724 ✭✭✭Metric Tensor


    Falcon L wrote: »
    We've never felt uncomfortable in the house and stuffy it aint. :cool:

    This is a fair point. If you're the type of person who will have the windows open in the middle of December then MHRV is not for you.

    A good regime of purge ventilation using windows and cross-flow is adequate for ventilation.

    Obviously a lot of heat escapes when you do this so if you were heating the house to the same temperature as other people who don't open windows as often you will spend more on heat. Of course if you like the windows open you probably don't like the temperature as high as other people!


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    #16
    ht9zni1gs28crp
    Closed Accounts Posts: 1,011 ✭✭✭ht9zni1gs28crp


    Makes no sense whatsoever, why put all that expense of Insulation in only to heat the air then watch it piss through the fabric?

    If 4-6k on a MHRVC system bothers you now wait until the quote comes in to fill that 250mm cavity.....


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    #17
    BarneyMc
    Registered Users Posts: 1,504 ✭✭✭BarneyMc


    My advice is to go with the air tightness route. Air leakage can vary considerable - you could end up with a house that's ventilated naturally just to your liking but that's very unlikely - you'll probably end up with a very draughty house and you'll be spinning the roulette wheel when it comes to seeing how well your insulation works in practice.


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    #18
    Metric Tensor
    Registered Users Posts: 3,724 ✭✭✭Metric Tensor


    To add to my previous post re using windows regularly for purge ventilation -

    This is still no reason not to have good air-tightness details. Just because you are using the opening sections of your windows to ventilate that is no reason to allow air to leak in and out around every penetration and junction in the wall!


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    #19
    Falcon L
    Closed Accounts Posts: 891 ✭✭✭Falcon L


    Metric Tensor wrote: »
    To add to my previous post re using windows regularly for purge ventilation -

    This is still no reason not to have good air-tightness details. Just because you are using the opening sections of your windows to ventilate that is no reason to allow air to leak in and out around every penetration and junction in the wall!
    Yep, it wouldn't make sense to build without air-tightness. My house is built to air tight standards... apart from the big holes in the walls. :D


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    #20
    Metric Tensor
    Registered Users Posts: 3,724 ✭✭✭Metric Tensor


    Falcon L wrote: »
    Yep, it wouldn't make sense to build without air-tightness. My house is built to air tight standards... apart from the big holes in the walls. :D

    Which, of course, are covered over for the air-tightness test!


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    #21
    ArraMusha
    Registered Users Posts: 589 ✭✭✭ArraMusha


    Thanks for your post 'falcon l'. A number of very Interesting facts in your post. Mainly that you referred to the conventional methods which most new builds are following ie. High insulation leads to air tight, leads to HRV.....

    Also interesting was the low heating cost, thanks for sharing, and I assume the relatively low upfront costs for oil and stove. Also you mention that your house is not stuffy and i doubt there is any black mold.
    Sounds like this is the heating system I'll be going for with some PV's for part L. As regards ventilation I'm looking at a mechanical system that fits over the hole in the wall.
    That mini heatpump that just heats your hot water sounds interesting...must look into that also. Heatpump technology is impressive and the theory is sound. Its the upfront investment cost of a larger system that is prohibitive right now.


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    #22
    ht9zni1gs28crp
    Closed Accounts Posts: 1,011 ✭✭✭ht9zni1gs28crp


    ArraMusha, go and have a look at NZEB Open day and go visit a low energy example. It will convert you and restyle your way of thinking..


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    #23
    ArraMusha
    Registered Users Posts: 589 ✭✭✭ArraMusha


    miller_63 wrote: »
    ArraMusha, go and have a look at NZEB Open day and go visit a low energy example. It will convert you and restyle your way of thinking..
    Not convinced based on the above. Just met another heatpumper today sorry he ever installed it. Seems like we're at the stage where the bad experiences related to heatpumps and hrv are being resolved but we are not there yet. I'm all for the "latest and greatest" but on this one oil and stove and mechanical vents wins over conventional systems, sorry ladz.

    Having said that I'll be firing in pipes for a heatpump as the jury are still out
    ...drinkin tay... all the best, and cosy homes to everyone.


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    #24
    ArraMusha
    Registered Users Posts: 589 ✭✭✭ArraMusha


    miller_63 wrote: »
    ArraMusha, go and have a look at NZEB Open day and go visit a low energy example. It will convert you and restyle your way of thinking..
    Not convinced based on the above. Just met another heatpumper today sorry he ever installed it. Seems like we're at the stage where the bad experiences related to heatpumps and hrv are being resolved but we are not there yet. I'm all for the "latest and greatest" but on this one oil and stove and mechanical vents wins over conventional systems, sorry ladz.

    Having said that I'll be firing in pipes for a heatpump as the jury are still out
    ...drinkin tay... all the best, and cosy homes to everyone.


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    #25
    893bet
    Registered Users Posts: 8,830 ✭✭✭893bet


    ArraMusha wrote: »
    Not convinced based on the above. Just met another heatpumper today sorry he ever installed it. Seems like we're at the stage where the bad experiences related to heatpumps and hrv are being resolved but we are not there yet. I'm all for the "latest and greatest" but on this one oil and stove and mechanical vents wins over conventional systems, sorry ladz.

    Having said that I'll be firing in pipes for a heatpump as the jury are still out
    ...drinkin tay... all the best, and cosy homes to everyone.

    There are loads of people with MVHR and/or heat pumps who are very happy.

    You are choosing to listen to the opinions that back up what you want to do.

    Get your DEAP done then you will k ow what you can and can't do!


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    #26
    ht9zni1gs28crp
    Closed Accounts Posts: 1,011 ✭✭✭ht9zni1gs28crp


    I think your mindset isn't for changing given what your listening to and not paying heed to what we are telling you.
    'Not convinced based on the above'' statement in response to an event that hasn't even happened yet?

    An event that may take three hours of your time on a Saturday or Sunday which you aren't prepared to do...yet could effect the standard of your living for the next thirty years.



    A wise man has open ears....


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    #27
    BarneyMc
    Registered Users Posts: 1,504 ✭✭✭BarneyMc


    ArraMusha wrote: »
    Not convinced based on the above. Just met another heatpumper today sorry he ever installed it. Seems like we're at the stage where the bad experiences related to heatpumps and hrv are being resolved but we are not there yet. I'm all for the "latest and greatest" but on this one oil and stove and mechanical vents wins over conventional systems, sorry ladz.

    There will always be bad examples. What airtightness and insulation levels did this lad achieve? Or did he just 'stick in' a heat pump?

    You are choosing the system with the intrinsic poor performance based on the fact that 'it works' rather than the system that will give you a much better performance unless commissioned incorrectly.

    Build with your house in mind in 10 years time rather than 10 years ago.


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    #28
    sydthebeat
    Subscribers Posts: 41,253 ✭✭✭✭sydthebeat


    Reminds me of a guy i know who installed a geothermal heat pump system into a house with rads and natural ventilation, and then gave out about how high his electricity bills were.


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    #29
    Metric Tensor
    Registered Users Posts: 3,724 ✭✭✭Metric Tensor


    I'm going to buck the trend a bit here -

    On some of the new houses I recommend high efficiency condensing oil fired boilers with rads rather than heat pumps. When I discuss with the client how they propose to live and what they expect from a heating system I often find that their proposed lifestyle is not best suited to a heat pump / uf lifestyle.

    It's amazing how little oil is actually used to keep a new house warm, particularly when coupled with appropriate thermal mass and a good MHRV system.

    I always require good air-tightness detailing from the contractor and I always recommend MHRV. (Sometimes the clients don't agree regarding MHRV and if so we look at alternatives!)


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    #30
    cyfac
    Registered Users Posts: 86 ✭✭cyfac


    Metric Tensor wrote: »
    I'm going to buck the trend a bit here -

    On some of the new houses I recommend high efficiency condensing oil fired boilers with rads rather than heat pumps. When I discuss with the client how they propose to live and what they expect from a heating system I often find that their proposed lifestyle is not best suited to a heat pump / uf lifestyle.

    It's amazing how little oil is actually used to keep a new house warm, particularly when coupled with appropriate thermal mass and a good MHRV system.

    I always require good air-tightness detailing from the contractor and I always recommend MHRV. (Sometimes the clients don't agree regarding MHRV and if so we look at alternatives!)


    Hi all

    Im going to go with tensor on this one we built our house with the emphasis on high spec insulation air tightness HRV and high spec TG glazing we were lucky our site was south gacing and the architect laid out the house so all habitable rooms were south facing our architecht advised by going this route we would only need a mimimum amout of heating and as such a good condenser boiler with rads would suffice spend the money in the insulation hrv etc he advised and he was right i half filled the tank 3 years ago and its still over a quarter full


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    #31
    JimmyMW
    Registered Users Posts: 695 ✭✭✭JimmyMW


    ArraMusha wrote: »
    Not convinced based on the above. Just met another heatpumper today sorry he ever installed it. Seems like we're at the stage where the bad experiences related to heatpumps and hrv are being resolved but we are not there yet. I'm all for the "latest and greatest" but on this one oil and stove and mechanical vents wins over conventional systems, sorry ladz.

    Having said that I'll be firing in pipes for a heatpump as the jury are still out
    ...drinkin tay... all the best, and cosy homes to everyone.

    I am afraid that "new" technology like heat pumps etc get a bad name due to a number of different factors

    1. The designer has not got a clue and does not consider a house as a whole, they often do not pair the heating system with the building fabric or other systems, ie thermal mass (Concrete Block with external or cavity insulation) ideally requires a constant system like a heat pump to keep the heat consistant in the house, while a timber frame which is thermally responsive will work best with a supply on demand system ie rads & oil

    2. Poor design of floor layout with regards to orientation and solar gain

    3. Users keep turning off systems which are designed to regulate themselves due to the lack of knowledge, and end up opening windows in the morning on houses with MHRV etc

    4. Poor installers, I find that a lot of installers out there do not know much about how the system they are installing actually works with other building systems or fabric, this therefore leads back to point one, and the client is then fully reliant on their designer

    You will find poor examples of every system, its foolish to judge any one system based on someones opinion without knowing what else is going on in the house regarding the the other systems they have, the building fabric, the orientation of the house, and how they are using the house.


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