Part L / Ber complaince

bagio

Hello all,
I have a query regarding part L 2008 & ber compliance.
I aim to provide my renewable energy with solar and wood only burning stove as secondary heat source(space heating),main heat source oil condenser boiler.
This in theory would provide the 10kw per annum of renewable needed.
in deap when i enter that i am using natural ventilation i meet part L Compliance, although when i enter that i intend to use heat recovery ventilation and an air tightness of 1.77 then it tells me that i am not part L compliant and my renewable is 9.4 , slightly under 10 as required.
this seems strange as when i aim to air tight the house to a good standard and put in a heat recovery ventilation system, theoretically more energy efficient than holes in the wall I don't pass and when i enter that i am going for natural ventilation then it passes the 10kw requirement.
i know it is more than likely that the heat recovery uses electricity thus affecting the result but surely it is still more efficient to air tight and heat recover to not?
also deap selects a 1400 kw or so usage for heat recovery which cannot be changed,is this relative to the square meterage of the house or how is this figure calculated by deap.?
should i be worried about the slight shortfall?
incidentally the u values of the house are v good, walls .19, roof .15 , floors .15, glazing triple .9 etc.
the house receives an A3
any one any comments on this

BryanF

the deap system acts like a ratio with regards to the renewable requirement - as you improve your homes efficiency DEAP keeps upping the renewable requirement. in your case in my humble personnel opinion, input the natural ventiatlion tab and move on with your build;)

what you discuss above is a major flaw in our EPC system - and of course this retarded system is unique to Ireland

to any potential self-builders out there - THIS is why you need to consider your BER/part L requirements AT DESIGN STAGE

sydthebeat

bagio wrote: »

Hello all,
I have a query regarding part L 2008 & ber compliance.
I aim to provide my renewable energy with solar and wood only burning stove as secondary heat source(space heating),main heat source oil condenser boiler.
This in theory would provide the 10kw per annum of renewable needed.
in deap when i enter that i am using natural ventilation i meet part L Compliance, although when i enter that i intend to use heat recovery ventilation and an air tightness of 1.77 then it tells me that i am not part L compliant and my renewable is 9.4 , slightly under 10 as required.
this seems strange as when i aim to air tight the house to a good standard and put in a heat recovery ventilation system, theoretically more energy efficient than holes in the wall I don't pass and when i enter that i am going for natural ventilation then it passes the 10kw requirement.
i know it is more than likely that the heat recovery uses electricity thus affecting the result but surely it is still more efficient to air tight and heat recover to not?
also deap selects a 1400 kw or so usage for heat recovery which cannot be changed,is this relative to the square meterage of the house or how is this figure calculated by deap.?
should i be worried about the slight shortfall?
incidentally the u values of the house are v good, walls .19, roof .15 , floors .15, glazing triple .9 etc.
the house receives an A3
any one any comments on this

What deap its saying is that the more efficient your build, the less requirement you have from your panels + stove, thus the reduced renewable figure. This is a serious flaw with deap and its becoming more and more obvious.

I'm posting from phone but il bet some of the other posters will link to previous threads and articles on this.

fclauson

Ooohh my favorite topic - see my many posts on the topic

see my artical in Cxxxxxxt Ixxxxxxd

it hightlights this exact issue - DEAP is not fit for purpose for a low energy build

sinnerboy

Have a look here for a similar discussion

bagio

Had a good look there at other posts and discussions , and thanks to all for points of view.


I agree that the deap seem flawed for low energy housing as per previous posts and also agree that the renewable requirement should be based on a percentage of actual energy required to heat the house, this makes a lot more sense the the deap.

even if the house uses less energy than a similar house with natural ventilation.the natural ventilated house will get renewable pass and mine wont?seems strange

one thing though , it is still down to engineer to sign off and by deap if my house falls short on renewables , 9.4 in place 10 required .

Would i be right in saying that in order for my engineer to sign off the ber must show a pass on all part L requirements?

BryanF

bagio wrote: »

Had a good look there at other posts and discussions , and thanks to all for points of view.


I agree that the deap seem flawed for low energy housing as per previous posts and also agree that the renewable requirement should be based on a percentage of actual energy required to heat the house, this makes a lot more sense the the deap.

even if the house uses less energy than a similar house with natural ventilation.the natural ventilated house will get renewable pass and mine wont?seems strange

one thing though , it is still down to engineer to sign off and by deap if my house falls short on renewables , 9.4 in place 10 required .

Would i be right in saying that in order for my engineer to sign off the ber must show a pass on all part L requirements?

Yes but Mvhr is not a requirement of the current regs..

fclauson

Please do read the artical in CI

You do have a choice if DEAP does not show compliance but here is the response from the DOE

a) does the department have an official position regarding an acceptable alternative way of meeting the renewables obligation?

Response: Technical Guidance Document L outlines how the statutory requirements of Part L (Conservation of Fuel and Energy) of the Second Schedule to the Building Regulations may be achieved in practice. This includes the requirements in relation to sourcing a reasonable proportion of energy from renewable energy sources. Works which are carried out in accordance with TGD L are accepted, prima facie, meeting the statutory requirement. TGD L, as is the case with all TGDs published by the Department, recognises that approaches other than those outlined may be used and this is not precluded. The Department's official position therefore is that it recognises and accepts that altenative appropaches can be used. However the onus is on those whose design and construction relies on alternative approaches to demonstrate the equivalence of the alternative approach used. It is reasonable and necessary that the Department should demonstrate how compliance can be achieved in practice. It is not the role of the department to define or provide guidance on alternative approaches.