New Build Advise

thatslife

Hey Folks,
I'm in the design stage of our new home (2400sqft) two storey and there are some very knowledgeable people on boards that could help stop this rapid spread of grey hair!!
I've looked through all the different threads but its hard to nail down some proper conclusions.
My plan is geothermal - horizontal ground source for heating UFH and hot water.
- Worried about my soil; its well drained and bedrock about 2m down, will i get the proper return?
- Is it worth adding in Solar Panels for H/W only, to save the HP's workload
From what I've read here, widen cavity and keep insulation together.
- Fill cavity or Not?
I hadnt planned to airtighten the house e.g. there will be a chimney in one of the sitting rooms
- Is HRV necessary? Does it work right on unsealed envelopes? Any other options bar vents in the rooms?
I've read here also that 'its important to properly design the system'
-can anyone point me right direction to a company/person who is trustworthy and up to speed?
We are going to the Ideal homes show in Dublin to gather up info also.

I really appreciate any answers/help. It'll be nice to make a wise intial investment to save the monthly outgoings in the future.
Thanks

sydthebeat

its almost impossible to answer all those questions in isolation as each one affects the other.

for example :
no HRV will mean much more insulation in your structure.
Including a chimney destroys the benefit of a HRV system.
You MUST make your home air tight.


Firstly get your home designed to suit your needs, then get a provisional DEAP assessment done from those plans with different options as to how to comply.

believe me what i say that 2011 regs are EXTREMELY onerous and difficult to comply with.

MicktheMan

thatslife wrote: »

1 can anyone point me right direction to a company/person who is trustworthy and up to speed?

2 It'll be nice to make a wise intial investment to save the monthly outgoings in the future.
Thanks

1 Where are you building?

2 Have you considered passive?

Dardania

ANother option to a full blown HRV system (no pun intended) is a Demand Controlled Ventilation system, like this: http://www.aereco.ie/wp-content/uploads/2012/02/FLY510GB_DCMEV-Guidance-for-Residential-Installations.pdf.pdf

I have retrofitted one to my home, and find it excellent. Cheaper and easier than HRV, with less maintenance, but will consume more energy than a HRV.

This will work with a draughty or airtight house, but is most effective in an air tight house.

For the fireplace, if it's open, it's a massive energy loser. I read somewhere that when operating you lose 80% heat from it, when not operating, you lose 100%. Have you considered a room sealed stove fireplace? I have my eye on something like this for my house if I get funds together: http://borustoves.ie/fiachra-7kw-insert-stoves/

I've no experience with geothermal, but guys do swear by it. And air to water heat pumps also... I'd be worried about the temperatures it producing not being high enough for hot water storage i.e. don't they hit 40C, when you need 60C for hot water storage?

With solar, I have specified the controls for it before, and it was purely sized for hot water

thatslife

MicktheMan wrote: »

1 Where are you building?

2 Have you considered passive?

Building in Co Longford.

I'm looking into passive but Im worried about the costs involved.

thatslife

Dardania wrote: »

ANother option to a full blown HRV system (no pun intended) is a Demand Controlled Ventilation system, like this: http://www.aereco.ie/wp-content/uploads/2012/02/FLY510GB_DCMEV-Guidance-for-Residential-Installations.pdf.pdf

I have retrofitted one to my home, and find it excellent. Cheaper and easier than HRV, with less maintenance, but will consume more energy than a HRV.

This will work with a draughty or airtight house, but is most effective in an air tight house.

For the fireplace, if it's open, it's a massive energy loser. I read somewhere that when operating you lose 80% heat from it, when not operating, you lose 100%. Have you considered a room sealed stove fireplace? I have my eye on something like this for my house if I get funds together: http://borustoves.ie/fiachra-7kw-insert-stoves/

I've no experience with geothermal, but guys do swear by it. And air to water heat pumps also... I'd be worried about the temperatures it producing not being high enough for hot water storage i.e. don't they hit 40C, when you need 60C for hot water storage?

With solar, I have specified the controls for it before, and it was purely sized for hot water

thanks for that, I'll look into it.

Yes I probably should have mentioned it will be enclosed fireplace with stove/backboiler. The Heat Pumps I'm looking at are spec'd to do 65C hot water.
http://www.seai.ie/Your_Building/BER/BER_Assessors/Technical/HARP_Database/Heat_Pumps/?f=1&type=Brine+to+water

thatslife

sydthebeat wrote: »

its almost impossible to answer all those questions in isolation as each one affects the other.

for example :
no HRV will mean much more insulation in your structure.
Including a chimney destroys the benefit of a HRV system.
You MUST make your home air tight.


Firstly get your home designed to suit your needs, then get a provisional DEAP assessment done from those plans with different options as to how to comply.

believe me what i say that 2011 regs are EXTREMELY onerous and difficult to comply with.

Do the planning offices now run your plans throught this DEAP s/w to see if you comply?

sydthebeat

thatslife wrote: »

Do the planning offices now run your plans throught this DEAP s/w to see if you comply?

absolutely no... your local authority has no interest whatsoever in how you build your home.

thatslife

sydthebeat wrote: »

absolutely no... your local authority has no interest whatsoever in how you build your home.

Ok so its just for your own benefit as a guideline to get the most efficient build. Why are they called regulations then? Or what/who are we complying to?

Condenser

From what you've mentioned about the soil it sounds perfect for horizontal system.

Personally I would be aiming for an A3 rating which when teamed up with a good heat pump will leave your running costs at an absolute minimum. A3 is not that hard to achieve.

Airtightness is an option but not absolutely essential. In my experience there is not alot of difference in running costs between a well built well insulated house that cuts out all major points of air infiltration, i.e chimeys, around windows, soffits etc and that of a similarly insulated house that goes fully air tight which is an hugely involved process.

I would concentate my funds on a good insulation spec and a good heat pump. Then if the budget allows go airtight with HRV.

Do not use a heat pump that tries to produce 65C for hot water unless you like replacing compressors every 6 or 7yrs. Theres better ways of producing hot water without needing to force a HP up to temps it can't handle like fresh hot water systems which use an intermediary heat exchanger on the hot water tank and only need 45-50C

thatslife

Condenser wrote: »

From what you've mentioned about the soil it sounds perfect for horizontal system.

Personally I would be aiming for an A3 rating which when teamed up with a good heat pump will leave your running costs at an absolute minimum. A3 is not that hard to achieve.

Airtightness is an option but not absolutely essential. In my experience there is not alot of difference in running costs between a well built well insulated house that cuts out all major points of air infiltration, i.e chimeys, around windows, soffits etc and that of a similarly insulated house that goes fully air tight which is an hugely involved process.

I would concentate my funds on a good insulation spec and a good heat pump. Then if the budget allows go airtight with HRV.

That sounds like a better option. There shouldnt be any mould issues if I do what you recommend right? There would be enough fresh air going through the house? Do u think teaming up with solar would be a good idea?

Condenser

thatslife wrote: »

That sounds like a better option. There shouldnt be any mould issues if I do what you recommend right? There would be enough fresh air going through the house? Do u think teaming up with solar would be a good idea?

Not if you use a fresh water system in conjunction with the heat pump. The hot water costs would be so low that you'd never get a payback on the solar panels.

thatslife

Condenser wrote: »

Not if you use a fresh water system in conjunction with the heat pump. The hot water costs would be so low that you'd never get a payback on the solar panels.

Cheers man. I'll look into that. Vents in the Windows should be fine right?

MicktheMan

Condenser wrote: »

In my experience there is not alot of difference in running costs between a well built well insulated house that cuts out all major points of air infiltration, i.e chimeys, around windows, soffits etc and that of a similarly insulated house that goes fully air tight which is an hugely involved process.

As an engineer who tests houses for heatloss causes, I cannot agree with the above. Lack of airtightness is the no.1 reason why the majority of houses I test are cold, uncomfortable and costing the owner a small fortune to heat. And I'm not talking about old houses either, in fact, generally houses built in the last ten years with "excellent" insulation (both specified and installed) are often the worst offenders.

blast06

sydthebeat wrote: »

absolutely no... your local authority has no interest whatsoever in how you build your home.

Hmmm .... about 2 months after i sent in a commencement notice to Westmeath Co Co i got a letter out from them looking for confirmation that the building being constructed would comply with part L - they referenced use of the DEAP software to create a report. I sent in mine and haven't heard of anything since.

To 'thatslife' ..... i would advice getting your house 'designed' to comply with part L. Don't necessarily trust your engineer to draw your plans as they are may not have knowledge of all the finer details required.
One additional thing i went with (roof nearing completion) is Quinn lite blocks on inner leaf and on 1st block above raft .... benefit of building the 1st line of internal wall blocks with Quinn lite is reduce cold bridging up from your foundations. Benefit of building the inner leaf with them is both the cold bridging from below and additional insulation + thermal mass. I'm no expert on this so perhaps other may be able to summarise this better

fclauson

blast06 wrote: »

Hmmm .... about 2 months after i sent in a commencement notice to Westmeath Co Co i got a letter out from them looking for confirmation that the building being constructed would comply with part L - they referenced use of the DEAP software to create a report. I sent in mine and haven't heard of anything since.

To 'thatslife' ..... i would advice getting your house 'designed' to comply with part L. Don't necessarily trust your engineer to draw your plans as they are may not have knowledge of all the finer details required.
One additional thing i went with (roof nearing completion) is Quinn lite blocks on inner leaf and on 1st block above raft .... benefit of building the 1st line of internal wall blocks with Quinn lite is reduce cold bridging up from your foundations. Benefit of building the inner leaf with them is both the cold bridging from below and additional insulation + thermal mass. I'm no expert on this so perhaps other may be able to summarise this better

Quinn or similar can be used at the base of the wall but for the rest I would go with a slightly wider cavity and get the thermal mass from regular block
Cannot lay my hands on my calcs - but quinn is equiv to abotu 2cm of bead

thatslife

blast06 wrote: »

Hmmm .... about 2 months after i sent in a commencement notice to Westmeath Co Co i got a letter out from them looking for confirmation that the building being constructed would comply with part L - they referenced use of the DEAP software to create a report. I sent in mine and haven't heard of anything since.

To 'thatslife' ..... i would advice getting your house 'designed' to comply with part L. Don't necessarily trust your engineer to draw your plans as they are may not have knowledge of all the finer details required.
One additional thing i went with (roof nearing completion) is Quinn lite blocks on inner leaf and on 1st block above raft .... benefit of building the 1st line of internal wall blocks with Quinn lite is reduce cold bridging up from your foundations. Benefit of building the inner leaf with them is both the cold bridging from below and additional insulation + thermal mass. I'm no expert on this so perhaps other may be able to summarise this better

Im definitely no expert!! Are you air tightning your house?

Condenser

MicktheMan wrote: »

As an engineer who tests houses for heatloss causes, I cannot agree with the above. Lack of airtightness is the no.1 reason why the majority of houses I test are cold, uncomfortable and costing the owner a small fortune to heat. And I'm not talking about old houses either, in fact, generally houses built in the last ten years with "excellent" insulation (both specified and installed) are often the worst offenders.

I didn't advocate a leaky poorly built structure. I've worked on hundreds of houses and I've seen it from all angles and I can catagoricly say that the statement I made above is true as I have hundreds of energy readouts to prove. Eliminate the major areas of air leakage and the difference between running a house like that and an airtight house with HRV is minimal. In fact a badly designed HRV can make things many times worse and if run to recommended airflow rates merely dumps massive amounts of energy for no good reason.

thatslife

MicktheMan wrote: »

As an engineer who tests houses for heatloss causes, I cannot agree with the above. Lack of airtightness is the no.1 reason why the majority of houses I test are cold, uncomfortable and costing the owner a small fortune to heat. And I'm not talking about old houses either, in fact, generally houses built in the last ten years with "excellent" insulation (both specified and installed) are often the worst offenders.

So Mick you're in this business? So you reckon passive is the right way to do it? Ball park figure - how much are you talking to air tight a house of 2400sqft (2-storey). Doing it the right way of course...

thatslife

Condenser wrote: »

I didn't advocate a leaky poorly built structure. I've worked on hundreds of houses and I've seen it from all angles and I can catagoricly say that the statement I made above is true as I have hundreds of energy readouts to prove. Eliminate the major areas of air leakage and the difference between running a house like that and an airtight house with HRV is minimal. In fact a badly designed HRV can make things many times worse and if run to recommended airflow rates merely dumps massive amounts of energy for no good reason.

Condenser, how are these houses ventilated?

MicktheMan

Condenser wrote: »

I didn't advocate a leaky poorly built structure. I've worked on hundreds of houses and I've seen it from all angles and I can catagoricly say that the statement I made above is true as I have hundreds of energy readouts to prove. Eliminate the major areas of air leakage and the difference between running a house like that and an airtight house with HRV is minimal.

As the OP has said that he/she is not an expert in building and many reading/posting here are in the same boat, I think that it is unhelpful to suggest that airtightness is not essential. So what does "airtightness" mean? Is it building to the regs? Curious, would you consider a house built to 2011 airtightness regs as a "well built house" or a "leaky poorly built structure"?

Anyone building or thinking of building today would be, imo, mad to ignore the effect of lack of airtightness on their energy consumption in the future.

I'm genuinly interested in your energy readouts. Any chance of seeing a graph of real (i.e. test results) airtightness data versus your energy readouts?

Condenser wrote: »

In fact a badly designed HRV can make things many times worse and if run to recommended airflow rates merely dumps massive amounts of energy for no good reason.

Agreed. Same goes for anything else poorly designed / commissioned / serviced / maintained.

MicktheMan

thatslife wrote: »

1. So Mick you're in this business?
2. So you reckon passive is the right way to do it?
3. Ball park figure - how much are you talking to air tight a house of 2400sqft (2-storey). Doing it the right way of course...

1. Yes, ph consultant engineer.
2. Whether building or renovating, passive principles should be considered seriously at design stage and applied intelligently and not just the capital costs considered. Whether passive or not, as much as can be done to get the best thermal envelope possible is the way to go because it is cannot easily be upgraded properly in the future.
3. Depends a lot on the design and structure (how long is a piece of....) but by optimising airtightness at design stage will reduce the cost versus "bolting it on" as an after thought.
Simple examples which don't cost much; moving electrical sockets from external walls to internal walls, getting the work order right etc. Design/build team (incl subbies) need to be up to speed on airtightness, target set in house specs, and someone on the build team made responsible for airtightness.

thatslife

MicktheMan wrote: »

1. Yes, ph consultant engineer.
2. Whether building or renovating, passive principles should be considered seriously at design stage and applied intelligently and not just the capital costs considered. Whether passive or not, as much as can be done to get the best thermal envelope possible is the way to go because it is cannot easily be upgraded properly in the future.
3. Depends a lot on the design and structure (how long is a piece of....) but by optimising airtightness at design stage will reduce the cost versus "bolting it on" as an after thought.
Simple examples which don't cost much; moving electrical sockets from external walls to internal walls, getting the work order right etc. Design/build team (incl subbies) need to be up to speed on airtightness, target set in house specs, and someone on the build team made responsible for airtightness.

whats you're rates?!?

Condenser

thatslife wrote: »

Condenser, how are these houses ventilated?

Some use DCV others just simple window vents and others with HRV. All of the houses are on heat pumps with electrical meters fitted to monitor consumption and I can hand on heart say I have not seen any significant difference in running costs between those that are airtight and those that focused on getting the insulation right and getting airtight on the major points of infiltration I mentioned before.

In similar size houses with similar insulation I would rarely see more than a 10% difference.

muffler

thatslife wrote: »

whats you're rates?!?

Enough.

This is a discussion forum and not somewhere to solicit quotes. I would strongly advise you to read the forum charter before posting again

thatslife

muffler wrote: »

Enough.

This is a discussion forum and not somewhere to solicit quotes. I would strongly advise you to read the forum charter before posting again

Sorry muffler. Amateur mistake.

blast06

thatslife wrote: »

Im definitely no expert!! Are you air tightning your house?

Yes - absolutely.
I've spent endless hours reading up on this and would i guess side with MicktheMan on the debate below but only in the ha'penny place in terms of knowledge compared to the 2 boys.

Back on the Quinn lite blocks ... another factor i didn't mention is having a more solid feel to the external walls than if i had a 2" insulated slab... or so goes the theory !

thatslife

blast06 wrote: »

Yes - absolutely.
I've spent endless hours reading up on this and would i guess side with MicktheMan on the debate below but only in the ha'penny place in terms of knowledge compared to the 2 boys.

Back on the Quinn lite blocks ... another factor i didn't mention is having a more solid feel to the external walls than if i had a 2" insulated slab... or so goes the theory !

Did u get an engineer that was up to speed on the part L or did you do all you're homework and tell him what you wanted?

jakko86

Where is most likely to cause lack of airtightness besides windows doors sockets and fireplace? If i tape all windows and doors,seal sockets at condute,external air supply to stove, and scratch coat all external walls before insulation and slab and seal joist ends at external walls and install hrv would this go a long way to sealing house or am i only scratching the surface?Will be starting building soon so looking for opinions on airtightness also.Ive heard of a lot of courses on this and would like to do one anyone recommend one in limerick/clare area?or what do they cost?
Pm me on course if im breaking thread rules?

fclauson

jakko86 wrote: »

Where is most likely to cause lack of airtightness besides windows doors sockets and fireplace? If i tape all windows and doors,seal sockets at condute,external air supply to stove, and scratch coat all external walls before insulation and slab and seal joist ends at external walls and install hrv would this go a long way to sealing house or am i only scratching the surface?Will be starting building soon so looking for opinions on airtightness also.Ive heard of a lot of courses on this and would like to do one anyone recommend one in limerick/clare area?or what do they cost?
Pm me on course if im breaking thread rules?

You would be getting close - but remember on my house we where looking for a combined hole in the fabric about the same size as a 3 inch waven pipe - now that's a very small hole across 1200 sqM of fabric

jakko86

I presume hrv is a must rather than trickle vents on windows?

fclauson

In my view yes - you must comply with part F - and a house below 3 ACH needs HRV.

It also depends on you site - mine is very windy (I can see 45 wind turbines out of it !!) - and hence anything other than super airtight would have the heat sucked out of it