Heat recovery

pbergin

We are just about to start our build and I am interested in fitting a heat recovery system.
Can someone recommend a company in the midlands that could provide me with some information.
Also, our house is going to be block built, is it hard to seal a block house?

Thanks
P.

sydthebeat

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

pbergin,
All you need to know is in the above link. if you construct to those details then you will end up with a high standard of air tightness.....

ardara1

Hi Pbergin -

Houses 'reasonably' put together that are wet finished inside (an good sealed windows and doors - the openings not the frame) will generally achieve 6 or 7@q50 (about 0.3 air changes in our regs) - you MUST have 4 or under to make heat recovery effective (0.20) - follw the accreditted construction details as above - AND HAVE THE HOUSE TESTED. Problem is - you should test AFTER the house is completed with all services in.
If you put MVHR into a house that is leaky, it's like pressurising a sieve - it'll make the house LESS eficient!

sydthebeat

ardara, i spoke to a rep from an air tightness testing company at PLAN expo this year. He explained to me how he did a test on his 2 year old 3 bed semi, plasterboard bonded onto cavity masonry wall. He got a reading of 32@q50 :eek:

When the new regs come in an 10 is made the minimum value, i still expect many 'wet finished' dwellings to fail miserably...... a figure of 7 may be come the industry standard, and a figure of 3-4 would be considered best practice.

sunnysoutheast

hi pbergin

We have a blockbuilt house with HRV. We've been in about two months and I can say that I'd never now live in a house without it (even more so when you look at the alternatives). No condensation anywhere. Just make sure that you have a boost function in every bathroom (we also have an extract in our laundry/boiler room which means our washing dries overnight).

We used Proair who are nominally based in Galway but seem happy to travel.

In terms of detailing, major areas of focus should be cavity closing, sealing around opes, loft insulation, ceiling details e.g. spotlights and, if you use internal insulated boards, around sockets and switches. Our house isn't perfect (we made the late decision to add the boards) but I'm working through the final little things slowly.

We haven't had the house tested - and I wouldn't bother. €500+ and for what, exactly? Bear in mind you'll have a huge 2 sq.m. hole in your "envelope" every time you open an external door!

SSE

ardara1

sydthebeat wrote: »

ardara, i spoke to a rep from an air tightness testing company at PLAN expo this year. He explained to me how he did a test on his 2 year old 3 bed semi, plasterboard bonded onto cavity masonry wall. He got a reading of 32@q50 :eek:

When the new regs come in an 10 is made the minimum value, i still expect many 'wet finished' dwellings to fail miserably...... a figure of 7 may be come the industry standard, and a figure of 3-4 would be considered best practice.

Over a series of tests carried out by the BRE in the UK the worst score was 31 and that was only 1 house - your contact beats that - but I don't believe him, most guys doing air pressure tests are not accredited as they are in the UK YOu would need to leave front and back door open to get such results. Our regulations assume 10 Q50 - to explain that - it is a clear hole the size of a 1 Euro coin in every square metre of building fabric - roof - wall - floor - windows and doors. The average of the BRE study was 14.

ardara1

sunnysoutheast wrote: »

hi pbergin

We have a blockbuilt house with HRV. We've been in about two months and I can say that I'd never now live in a house without it (even more so when you look at the alternatives).

No condensation anywhere.

Just make sure that you have a boost function in every bathroom (we also have an extract in our laundry/boiler room which means our washing dries overnight).

We used Proair who are nominally based in Galway but seem happy to travel.

In terms of detailing, major areas of focus should be cavity closing, sealing around opes, loft insulation, ceiling details e.g. spotlights and, if you use internal insulated boards, around sockets and switches. Our house isn't perfect (we made the late decision to add the boards) but I'm working through the final little things slowly.

We haven't had the house tested -

and I wouldn't bother. €500+ and for what, exactly?

Bear in mind you'll have a huge 2 sq.m. hole in your "envelope" every time you open an external door!

SSE

You'll not get condensation if all the warm air is being pushed out of a leaky house - it's called a draught

What for exactly? - to ensure your MVHR system is saving more energy that expending it. MVHR in a leaky house is inefficient and is detrimental to a decent energy label

pbergin

Thanks for the info
I will take a read through that pdf, would we have to fit plaster board to the inside of the block wall? if so, can it be fitted directly to the wall or does it have to be on battons?

sunnysoutheast

hi ardara1

I don't disagree with you - in theory. I spoke to two companies a while back about pressure testing - I just got this uneasy feeling that I knew more about the subject than they did and the "fee" seemed to be a suspiciously transparent multiple of the sq.m. area. Also the tests have to be done when the house is "finished" so you are limited in what you can actually do with the results - I don't need an expert to tell me to ensure that opes are sealed and any doors/access to "cold" areas are draughtproofed, for example.

Also I wouldn't necessarily make the assumption that a block-built house is "leaky" - any method presents its own challenges and can be built well or badly.

SSE

ardara1

sunnysoutheast wrote: »

hi ardara1

I don't disagree with you - in theory. I spoke to two companies a while back about pressure testing - I just got this uneasy feeling that I knew more about the subject than they did and the "fee" seemed to be a suspiciously transparent multiple of the sq.m. area. Also the tests have to be done when the house is "finished" so you are limited in what you can actually do with the results - I don't need an expert to tell me to ensure that opes are sealed and any doors/access to "cold" areas are draughtproofed, for example.

Also I wouldn't necessarily make the assumption that a block-built house is "leaky" - any method presents its own challenges and can be built well or badly.

SSE

Morning Sunny,

71% percent of air leakage from a house is through the 'less obvious' areas - so window/door surrounds, window door openings/ loft hatches - are included in the 29% - in tests run by BRE it was junctions/cracks/bad detailing in the unexpected areas where the main problem lay -this is why they've published the accredited details - (Ireland also but to a lesser quality)
There is no accreditation scheme for testing in S Ireland - There's a company in Down that I've seen in operation - they're not allowed to issue their own certs - they MUST be verified by BRE or BSRIA.

I agree with your comment on build types - as I was saying wet rendered block are performing particularly well in NI, Timber FRame also can perform well - and badly - depends on workmanship.

If I was giving a contract to a builder it would state a specific air permeability that he must build to - and verified by a proper testing house.

s2_ireland

Hi pbergin,
qualityhrv are based in the midlands & will point you in the right direction re structural airtightness...
S2