Part L compliance

moch

I am building a house approx 2600sqft and trying to comply with part L.
The general spec is:
150mm pumped cavity
50mm insulated board
100mm insulation in floor
Plenty of insulation inside etc.
Wood burning double sided stove
Air to Water heat pump
Under floor heating, upstairs and downstairs
MHRV

The engineer is telling me even with the above, I may also need to add solar to comply, Solar will be an extra cost with no great benefit. This needs to be clarified next week,but has anyone else on here been through this or have any opinions, Thanks

sydthebeat

The ONLY way to determine compliance is to have a DEAP assessment carried out on the plans and specification.

sydthebeat

moch wrote: »

I am building a house approx 2600sqft and trying to comply with part L.
The general spec is:
150mm pumped cavity
50mm insulated board
100mm insulation in floor
Plenty of insulation inside etc.
Wood burning double sided stove
Air to Water heat pump
Under floor heating, upstairs and downstairs
MHRV

The engineer is telling me even with the above, I may also need to add solar to comply, Solar will be an extra cost with no great benefit. This needs to be clarified next week,but has anyone else on here been through this or have any opinions, Thanks

who advised you to go with an insulated board internally when you are installing a MHRV system ????

moch

The same engineer, tells me that 150mm pumped insulation is not enough.

sydthebeat

moch wrote: »

The same engineer, tells me that 150mm pumped insulation is not enough.

has he done a DEAP assessment??

why not just make the cavity wider?

how does he intend to achieve a good air tightness result with insulated boards?

moch

A provisional DEAP has been carried out but using general specs of stove, heat pump, MHRV etc.
Now all specs are gone in of the actual units I plan to use, so this will be inserted in DEAP next week to see the outcome.
The walls are already built and he told me to plaster walls before insulated boards are fitted.

sydthebeat

moch wrote: »

A provisional DEAP has been carried out but using general specs of stove, heat pump, MHRV etc.
Now all specs are gone in of the actual units I plan to use, so this will be inserted in DEAP next week to see the outcome.
The walls are already built and he told me to plaster walls before insulated boards are fitted.

1. i think you should wait until after the revised assessment to see what is required. no point worrying yourself over hypotheticals at this stage.

2. exact performance values of products will generally be better than default values probably used in the original assessment.

3. air to water heat pumps are not especially efficient and will struggle to provide the renewable requirement.

4. get your first fix services in before your render the walls

moch

Thanks for advice you are probably right about waiting, I just don't like the thoughts of spending money with no great added value if it comes to that.

quentingargan

If you do need to add further measures when you get the revised assessment, you can also consider solar photovoltaic. This is can be sized to meet your needs more easily than solar thermal. You may find that two or three modules is enough to meet requirements and would be cheaper and easier to install. Solar thermal is great but some households don't use enough hot water to justify the costs.

quentingargan

By the way, increased insulation doesn't guarantee Part L compliance, and in some passive houses makes compliance more difficult. For an example of this see http://passivehouseplus.ie/blogs/do-ireland-s-energy-efficiency-regulations-penalise-energy-efficiency.html.

sydthebeat

quentingargan wrote: »

By the way, increased insulation doesn't guarantee Part L compliance, and in some passive houses makes compliance more difficult. For an example of this see http://passivehouseplus.ie/blogs/do-ireland-s-energy-efficiency-regulations-penalise-energy-efficiency.html.

i think at this stage its generally accepted that passive certification would be acceptable by local authority BCOs as compliance with the regulations, even though not by the prima facia method.

the problem arises where the passive principles and assessment is applied, but no certification is sought..... then the question of how far you stretch the elastic applies.

BryanF

sydthebeat wrote: »

i think at this stage its generally accepted that passive certification would be acceptable by local authority BCOs as compliance with the regulations, even though not by the prima facia method.

the problem arises where the passive principles and assessment is applied, but no certification is sought..... then the question of how far you stretch the elastic applies.

imho an assigned certifier would be foolish to seek an exemption for part L compliance from the BOC, based on a 'non-certified' passivhaus method

sydthebeat

BryanF wrote: »

imho an assigned certifier would be foolish to seek an exemption for part L compliance from the BOC, based on a 'non-certified' passivhaus method

imho i dont think they get one

just do it

sydthebeat wrote: »

i think at this stage its generally accepted that passive certification would be acceptable by local authority BCOs as compliance with the regulations, even though not by the prima facia method.

the problem arises where the passive principles and assessment is applied, but no certification is sought..... then the question of how far you stretch the elastic applies.

Is this generally accepted now - certified passive negates need for renewable bling?

sydthebeat

just do it wrote: »

Is this generally accepted now - certified passive negates need for renewable bling?

there are BCOs out there who have accepted passive certification as a suitable method of Part L compliance

there was a letter in an edition of passivehouse+ last year (i think) from a BCO who explained why s/he would accept passive certification as a method of complaince

just do it

I'm just reading that letter by the BCO and the point being made is once >15% is being provided by renewables that would suffice, even though it might be less than the 10kWh/m2/yr target required in the TGD. The regulation only refers to having a "reasonable proportion" of energy supplied by renewables.

Thus a certified passive house still requires some renewable energy source.

just do it

And just to add the 10kWh/m2 target isn't what's potentially produced, what you're required to do is bring the BER down by 10kWh. Now I get the difficulty with passive houses having to provide extra renewables.

TommyC1982

Hi all just reading this thread and I am falling in to a tight spot.
We are finished building our house and now are having an issue with compliance on Part L 2011. Spec is as follows
140mm floor insulation
250 full fill cavity
150 mm spray foam on slope in the attic
0.84 on air tightness test
All internal wall sand and cement with skim on top
Diakin Heat pump
Zehnder comfoair HRV
All triple glazed windows
Wood burning stove.
I have just been told by my final BER assessor this is not good enough and I might have to install PV panels!! Guess what I don't have the money for these!!! My provisional BER done by a different assessor was compliant. So at the moment I am scr*wed. I need my BER cert to get my last €25K to pay the last of the bills.
Has anyone else been in this spot and how to get out of it?

sydthebeat

It's a ridiculous anomaly with the process that the more you make the build efficient, the less the heat pump offers as a renewable source.

Contact your local bco and explain the situation and see if they will provide a letter stating accepted compliance.

Alternatively, see if inputting a air tightness of the default 7 works. .. so that would be an air change rate of 0.35

quentingargan

What aspect of compliance are you having problems with? EPC? CPC? or the Renewable Energy component.

If it is the renewable component, you might be able to get away with de-rating as Sydthebeat suggested. If you want to PM the XML file (which your BER assessor can export) to others here they may have ideas on how to remedy the renewable part. If it is EPC and CPC, there is less likely to be an easy solution.

I now see you have a wood burning stove. So almost certainly it isn't renewables, but probably EPC. I have seen people take it out, leave the flue in place on the DEAP and retrofit the stove after the assessment. Others might have a view on the legitimacy of doing that, but I have seen houses for sale with a flue and no stove for this very reason..

MOTM

What exactly was the difference between the provisional and final rating?

RexBanner

Am likely to be the same position as you in the next few months - provisional rating was in compliance but we put in more efficient windows and are likely to attain a higher than target air-tightness score which will knock us out of compliance - so interested in hearing how you get on with this.

Will echo the above advice, get the xml file and download the DEAP tool, then check through all the information entered into the calculation, I found that my BER guy had entered some values incorrectly in the provisional analysis (floor area, room heights, etc) which, when adjusted, fixed brought us closer to the 10 score.

Also, some aspects of the house fabric may have changed during the build so make sure that these are updated too as they may help.

FiOT

Hi All,

I wonder if you guys have any updates on how your Part L compliance fared in the end?? Planning on trying to achieve compliance with ASHP and wood burning stove but worried now that it's a fine balance! Would love to hear how people went about meeting the regs in the end.

quentingargan

FiOT wrote: »

Hi All,

I wonder if you guys have any updates on how your Part L compliance fared in the end?? Planning on trying to achieve compliance with ASHP and wood burning stove but worried now that it's a fine balance! Would love to hear how people went about meeting the regs in the end.

Every house is so different, that what worked for one may not work for another. The only way to do this is to get the provisional BER done, and as suggeted by others here, get the XML file and play with the DEAP software yourself. You need to meet both renewable obligations and EPC / CPC. Your wood burning stove may make it more difficult to meet EPC as the efficiency would be low.

FiOT

quentingargan wrote: »

Every house is so different, that what worked for one may not work for another. The only way to do this is to get the provisional BER done, and as suggeted by others here, get the XML file and play with the DEAP software yourself. You need to meet both renewable obligations and EPC / CPC. Your wood burning stove may make it more difficult to meet EPC as the efficiency would be low.

I have the provisional BER which shows that we will meet the regs with the HP, stove and MHRV. Though I would imagine it's quite tight and we may be forgoing some insulation and using lower u value windows (1.10) to make this work. Seems like a very fine balance and that we could end up with having to get solar PV or something if one element is increased even slightly.

All very confusing, hard to know the right way to go about it. Will look into downloading the DEAP software.

quentingargan

FiOT wrote: »

I have the provisional BER which shows that we will meet the regs with the HP, stove and MHRV. Though I would imagine it's quite tight and we may be forgoing some insulation and using lower u value windows (1.10) to make this work. Seems like a very fine balance and that we could end up with having to get solar PV or something if one element is increased even slightly.

All very confusing, hard to know the right way to go about it. Will look into downloading the DEAP software.

If you have HRV, then a small amount of PV would be no bad thing, as you have a baseload that would use a fair share of the power coming from the PV. Also, by the time you build, there may well be a feed in tariff that makes PV stack.

I presume you're not actually going to reduce the insulation and put in cheaper windows?

Quentin.

FiOT

quentingargan wrote: »

I presume you're not actually going to reduce the insulation and put in cheaper windows?

Quentin.

Absolutely not, we have always said that our money would go towards a high spec "builders finish" if you get me. We are only in our 20s so no need for turn-key finish, we'll essentially live in 3 rooms for the foreseeable future! Insulation, air tightness and quality materials are our prerogative.

I guess we thought that meeting the regs with the HP alone might save us some money but I can't be happy with that if it is at the cost of downgrading materials.

Would you have any idea of the cost of Solar PV panels?

quentingargan

FiOT wrote: »

Absolutely not, we have always said that our money would go towards a high spec "builders finish" if you get me. We are only in our 20s so no need for turn-key finish, we'll essentially live in 3 rooms for the foreseeable future! Insulation, air tightness and quality materials are our prerogative.

I guess we thought that meeting the regs with the HP alone might save us some money but I can't be happy with that if it is at the cost of downgrading materials.

Would you have any idea of the cost of Solar PV panels?

Yes - ironic how Part L system intended to improve the energy efficiency of our buildings can hammer you for using a heat pump on a well insulated house. Maybe do a door-blower test with the back door open

In terms of PV costs, very roughly, you could expect to pay about €1,00 plus VAT for a two panel kit. Each additional panel about €250 depending on whether it pulled you into a larger inverter or not.

FiOT

quentingargan wrote: »

Yes - ironic how Part L system intended to improve the energy efficiency of our buildings can hammer you for using a heat pump on a well insulated house. Maybe do a door-blower test with the back door open

In terms of PV costs, very roughly, you could expect to pay about €1,00 plus VAT for a two panel kit. Each additional panel about €250 depending on whether it pulled you into a larger inverter or not.

Ok well we may just have to explore that a little further then. I was feeling very smug that we'd have it all done in one and no ugly panels on the front of our south facing house

I was speaking with a HP person at the self build show in September/October who was saying that there are changes coming down the line as to how HPs are viewed by the regs. He was saying he hoped it would be announced in December or the new year? Don't know what these changes are but I wonder would it impact on us... We aren't starting our build until March so we have a bit of wiggle room to wait and see.

GreenTech

I think some of the info here is a little speculative, to say the least. The building control authorities are not accepting PH certification as Part L compliance, nor can you omit renewable energy technologies from any dwelling unless you can demonstrate that your building consumes no energy whatsoever. Part L compliance is governed by law, PH certification is not. I have worked on various PH projects and basically what you need to prove for renewable requirements is below:

- Building regulations Technical Guidance Document Part L 2011 is as the name suggests... guidance on comply with the Building regulations Part L 2011. This document sets a target for renewable energy technologies of 10kWh/m2/yr from thermal sources and 4kWh/m2/yr from electrical sources.

-The ACTUAL building regulations, Part L 2011 is set out in SI 259/2011. Have a look on the Irish statute book website for this.
SI 259 - L3 requires (and I quote), 'providing that, for new dwellings, a reasonable proportion of the energy consumption to meet the energy performance of a dwelling is provided by renewable energy sources'.

Basically if you improve the energy performance of the dwelling envelope your demand for heat goes down. You are not 'exempt' from complying with the building regs if you build a PH. You are merely demonstrating that the proportion of renewable energy generated is equally as reasonable as building a typical Part L 2011 dwelling with 10kWh/m2/yr. For example if 10kWh/m2/yr represents 10% of a typical Part L 2011 dwellings primary energy demand, then you need to prove that proportionally your renewable energy system is providing 10% or higher of your total primary energy demand . The 10% is an arbitrary figure, I can't remember the exact figure but it needs to be calculated and demonstrated otherwise 10kWh is the target. Since this is a proportional target, the legislation would indicate that 0kWh is only acceptable where your primary energy demand is 0kWh ....as 0 is only proportional 0!

To answer the original query; If you are just about meeting the Part L regulations on your EPC (which is effectively the overall performance of the building), then you most likely need to produce 10kWh/m2/yr. Sometimes a heat pump will not achieve this and I have seen scenarios where this is the case. It is not straightforward to prove that your proportion of energy is adequate, but neither is it acceptable to simply dismiss the Part L 2011 regulations on the basis of PH certification, as some other points above would suggest. It's a risky gamble and could be challenged down the line unless you have calculations to prove compliance.

GreenTech

I think some of the info here is a little speculative, to say the least. The building control authorities are not accepting PH certification as Part L compliance, nor can you omit renewable energy technologies from any dwelling unless you can demonstrate that your building consumes no energy whatsoever. Part L compliance is governed by law, PH certification is not. I have worked on various PH projects and basically what you need to prove for renewable requirements is below:

- Building regulations Technical Guidance Document Part L 2011 is as the name suggests... guidance on how to comply with the Building regulations Part L 2011. This document sets a target for renewable energy technologies of 10kWh/m2/yr from thermal sources and 4kWh/m2/yr from electrical sources.

-The ACTUAL building regulations, Part L 2011 is set out in SI 259/2011. Have a look on the Irish statute book website for this.
SI 259 - L3 requires (and I quote), 'providing that, for new dwellings, a reasonable proportion of the energy consumption to meet the energy performance of a dwelling is provided by renewable energy sources'.

Basically if you improve the energy performance of the dwelling envelope your demand for heat goes down. You are not 'exempt' from complying with the building regs if you build a PH. You are merely demonstrating that the proportion of renewable energy generated is equally as reasonable as building a typical Part L 2011 dwelling with 10kWh/m2/yr. For example if 10kWh/m2/yr represents 10% of a typical Part L 2011 dwellings primary energy demand, then you need to prove that proportionally your renewable energy system is providing 10% or higher of your total primary energy demand . The 10% is an arbitrary figure, I can't remember the exact figure but it needs to be calculated and demonstrated otherwise 10kWh is the target. Since this is a proportional target, the legislation would indicate that 0kWh is only acceptable where your primary energy demand is 0kWh ....as 0 is only proportional 0!

To answer the original query; If you are just about meeting the Part L regulations on your EPC (which is effectively the overall performance of the building), then you most likely need to produce 10kWh/m2/yr. Sometimes a heat pump will not achieve this and I have seen scenarios where this is the case. It is not straightforward to prove that your proportion of energy is adequate, but neither is it acceptable to simply dismiss the Part L 2011 regulations on the basis of PH certification, as some other points above would suggest. It's a risky gamble and could be challenged down the line unless you have calculations to prove compliance.

sydthebeat

GreenTech wrote: »

I think some of the info here is a little speculative, to say the least. The building control authorities are not accepting PH certification as Part L compliance,

this has happened. A BCO has actually published a letter in Passive house + stating this very fact.

Every BCO is different.

For example if 10kWh/m2/yr represents 10% of a typical Part L 2011 dwellings primary energy demand

not in my experience

in a typical 2011 one off dwelling, the primary energy demand at the compliance threshold, in comparable figures, is 60kWh/m2/yr , so 10kWh/m2/yr is 17%.
I have not seen a dwelling with a 100kWh/m2/yr comply under 2011 regulations.

GreenTech

Every building control authority may be different but legislation is national legislation and indeed EU governed. The building control authority also do not sign off on a buildings compliance... assigned certifiers do (ie. architects, engineers etc.). The assigned certifier still takes the hit if a mistake has been made. Where legislation requires a proportion of energy to be from a renewable source, it is not open to any local authority or designer to ignore this, but to demonstrate compliance. Don't get me wrong, the PH standard is by far superior and it is generally the standard I work to, but it is ill advised to ignore Part L regulations in lieu of PH standards. There is not a PH in the country for which I could justify putting in oil burning appliances because they are 'too good to put in a renewable energy technologies'. It is bad practice in my view and bad advice to advise that a PH does not require renewable energy sources. PH buildings still consume energy. I would like to see the letter you refer to and see if there is a reference to not requiring 10kWh/m2/yr or not requiring any renewables at all. As I said earlier, compliance can be demonstrated by demonstrating that the renewable proportion is compliant, rather than a fixed output. FYI I don't work for the Dept of Environ so I'm not defending the regs. They are flawed. A building envelope should be optimised before introducing renewable energy technologies. This doesn't mean the regulations should be ignored in lieu of standards which do not form part of our legislation.

To clarify; I never stated that 10% was the 'target' proportion. As I stated originally, I used 10% as an arbitrary example. Whether its 17% or 100% is irrelevant. Renewable technologies should form a proportion of all new dwellings energy demand in order to comply with SI 259/2011. That is not open for debate. It is a fact and is written into legislation. The 10kWh/m2/yr target on the other hand is not legislation. My point is that it is open to any well informed individual to calculate this 'proportion' and prove that their building does actually comply, where they have installed a high efficiency heat pump in a very well insulated house, for example.

sydthebeat

You're basically agreeing with everything already said in this thread......

THE DON FANUCCI

new build starting in the new year: 2300 sq foot two storey, I'm going for 150mm pumped cavity, 150mm kingspan in floor, 300mm in attic, wood burning stove, good airtightness, mhrv, solar tubes, oil also - this should get me over the line for L-Regs I hope?? any help appreciated

quentingargan

THE DON FANUCCI wrote: »

new build starting in the new year: 2300 sq foot two storey, I'm going for 150mm pumped cavity, 150mm kingspan in floor, 300mm in attic, wood burning stove, good airtightness, mhrv, solar tubes, oil also - this should get me over the line for L-Regs I hope?? any help appreciated

Only way to know is to do a provisional BER assessment. Wood burning stove may help your renewables, but knacker your EPC

THE DON FANUCCI

Seriously considering thermodynamic solar panels. One 6x2foot panel on the roof. Job Done. Part L, water, heating, cost effective, job done. Anybody got experience with them?

Gumbo

THE DON FANUCCI wrote: »

Seriously considering thermodynamic solar panels. One 6x2foot panel on the roof. Job Done. Part L, water, heating, cost effective, job done. Anybody got experience with them?

Not good stories about them. Was considering them myself but got turned off them. A few threads on here about them.

delfagio

kceire wrote:

Not good stories about them. Was considering them myself but got turned off them. A few threads on here about them.

What made you get turned off them kceire??

Gumbo

delfagio wrote: »

What made you get turned off them kceire??

Pay back periods.
Cost of running them against gas system.

I was going to retrofit them in an extension/renovation but if I had to go new build where part L renewable was mandatory I may consider them then.

There's a big thread on here about them that I found while searching for info.

dathi

kceire wrote: »

There's a big thread on here about them that I found while searching for info.

latest from that tread is they seam to be losing their gas after 2 years resulting in a call out fee and regas charge (thats the ones that realize that it has happened, and the unit is using its built in emersion to heat the water)

Gumbo

dathi wrote: »

latest from that tread is they seam to be losing their gas after 2 years resulting in a call out fee and regas charge (thats the ones that realize that it has happened, and the unit is using its built in emersion to heat the water)

I've also heard there is a maintenance charge or service charge and it needs to be done every 2 years or so.