DEAP/BER Issues (Merged)

spacetherm

Sorry to be off topic slightly- newbie lack of protocol.
I have a project exercise which basically requires a 130m2 house with a primary energy consumption of 125.91 kwh/m2a (B3) to reduce consumption by at least 6,624 Kwh/m2/a to achieve a consumption of less than 75kwh/m2/a (A3) by using renewable technology alone.

My question is;- without upgrading the fabric of the house to improve heat loss, and not touching the existing 93% eff. oil fired condensing boiler space heating,
can A3 be achieved by installing solar thermal for water heating and PV for lighting, pumps etc.

The dwellings total primary energy consumption is currently 16,380 Kwh/m2/a

Any advise appreciated.
Thanks

sinnerboy

DEAP heavily penalizes electricity use. For every kw of energy demanded 2.7 kw is added on to the primary energy demand. So look to reduce electricity use or provide by renewables

sinnerboy

you mean

spacetherm wrote: »

The dwellings total primary energy consumption is currently 16,380 Kwh/m2/a

Any advise appreciated.
Thanks

spacetherm

Thanks sinnerboy, yes that would be some consumption all right!

So to put my question another way; if I reduce my energy consumption to less than 75 Kwh/m2/yr with renewables, even though the house fabric is leaking heat to B3 levels, I would still achieve an A3 rating?

I would like to see a completed example of the renewable technology input in the DEAP software to achieve A3, whilst the rest of the input in DEAP (without renewables) would have rated B3.

Is a fabric upgrade also essential to achieve A3 in the average house using renewables?

sinnerboy

spacetherm wrote: »

I have a project exercise ... to reduce consumption by using renewable technology alone.

Are you being straight here ? why are are you asking questions about fabric heat loss in this context ?

sinnerboy

spacetherm wrote: »

I would like to see a completed example of the renewable technology input in the DEAP software to achieve A3, whilst the rest of the input in DEAP (without renewables) would have rated B3.

Is that not the point of your project exercise ? In which case ... off you go and please report back .

sydthebeat

sounds like you want someone to do your homework for you?

if you reduce your energy consumption by using renewables, then obviously your fabric heat loss doesnt change. ???

what am i missing here?

creedp

sydthebeat wrote: »

sounds like you want someone to do your homework for you?

if you reduce your energy consumption by using renewables, then obviously your fabric heat loss doesnt change. ???

what am i missing here?

I have a related problem in that if I don't include a wood burning stove my heat pump complies in terms of the requirement to produce a min amount of heat demand from renewables. However, if I choose to also have a wood burning stove as a back up now DEAP requires that 10% of my heating demand comes from the stove and as the effciency of the stove is only 78% while the HP is at 387% I fail the renewables requirement. This seems really silly to me as installing a back up heat source that will use a renewable resource results in me failing the renewable requirement!

I understand that DEAP really doesn't like using electricity for home heating but this also confuses me as it seems the SEAI simply love electric powered card or hybrids that can be charged from the grid - Am I easily confused or is this policy rife with inconsistency?

BryanF

there's plenty more of those anomalies.. this is the software we have so, put up with it or petition you government representative / seai

sydthebeat

creedp wrote: »

I have a related problem in that if I don't include a wood burning stove my heat pump complies in terms of the requirement to produce a min amount of heat demand from renewables. However, if I choose to also have a wood burning stove as a back up now DEAP requires that 10% of my heating demand comes from the stove and as the effciency of the stove is only 78% while the HP is at 387% I fail the renewables requirement. This seems really silly to me as installing a back up heat source that will use a renewable resource results in me failing the renewable requirement!

I understand that DEAP really doesn't like using electricity for home heating but this also confuses me as it seems the SEAI simply love electric powered card or hybrids that can be charged from the grid - Am I easily confused or is this policy rife with inconsistency?

if you are using a HP you should be meeting the renewable requirement alone with it, unless the house is huge!!
are you including a MHRV system, what air tightness are you inputting, what heating controls etc.

your other point is another debate altogether. its off topic so if you want to continue it start a new thread.

creedp

sydthebeat wrote: »

if you are using a HP you should be meeting the renewable requirement alone with it, unless the house is huge!!
are you including a MHRV system, what air tightness are you inputting, what heating controls etc.

your other point is another debate altogether. its off topic so if you want to continue it start a new thread.

House is 2,800 sqft and all did a provisional BER which gave a TGD L 2008 renewable result of 14.1 kWh/m2y which was fine. Then I decided to install a MVHR system and overall airtightness system and ends up with 8 kWh/m3y if I uses the SAP Appendix Q data for the MVHR unit. However, if I use the defaul data for the MVHR Unit, i.e. make it less efficient I get a 9.9 kWh/m2y. It is difficult for me to understand why installing something which makes my house more efficient, i.e. reduces the consumption of electricity for the heat pump makes me non-compliant under the SEAI renewable requirements.

Sorry for off-topic rant (thanks BryanF for putting me straight) but I was simply making reference to the glaring inconsistencies in the SEAI policy approach to renewable energy.

sydthebeat

creedp wrote: »

House is 2,800 sqft and all did a provisional BER which gave a TGD L 2008 renewable result of 14.1 kWh/m2y which was fine. Then I decided to install a MVHR system and overall airtightness system and ends up with 8 kWh/m3y if I uses the SAP Appendix Q data for the MVHR unit. However, if I use the defaul data for the MVHR Unit, i.e. make it less efficient I get a 9.9 kWh/m2y. It is difficult for me to understand why installing something which makes my house more efficient, i.e. reduces the consumption of electricity for the heat pump makes me non-compliant under the SEAI renewable requirements.

Sorry for off-topic rant (thanks BryanF for putting me straight) but I was simply making reference to the glaring inconsistencies in the SEAI policy approach to renewable energy.

never use the default values in DEAP , they are ridiculously bad. use SAP like you did. also for MHRV youd want to be aiming at an airtigtness result of 3 or better for MHRV to be practical.

creedp

sydthebeat wrote: »

never use the default values in DEAP , they are ridiculously bad. use SAP like you did. also for MHRV youd want to be aiming at an airtigtness result of 3 or better for MHRV to be practical.

I fully agree with you but the problem I have come up against is that the more efficient my house becomes from a space heating perspective the more difficult it is to be compliant with TGD L 2008. As the point I was obviously unsuccessfully trying to make earlier, the more space heat required from my HP the better I will comply with TGD L 2008.

My BER assessor is looking at all this at present and thinks he has come up with a solution as long as the airtightness result is less that 4.3 which shouldn't be a problem as I am aiming for less than 3 or more to the point my builder is promising less than 3!!

Btw as a matter of interest are you prevented from using DEAP defaults if data for your system is included on Appendix Q? Just in case

sydthebeat

creedp wrote: »

I fully agree with you but the problem I have come up against is that the more efficient my house becomes from a space heating perspective the more difficult it is to be compliant with TGD L 2008. As the point I was obviously unsuccessfully trying to make earlier, the more space heat required from my HP the better I will comply with TGD L 2008.

My BER assessor is looking at all this at present and thinks he has come up with a solution as long as the airtightness result is less that 4.3 which shouldn't be a problem as I am aiming for less than 3 or more to the point my builder is promising less than 3!!

Btw as a matter of interest are you prevented from using DEAP defaults if data for your system is included on Appendix Q? Just in case

prevented? no, but why would you not use the better values?

i know what you mean by reducing space demand, however, the renewable requirement in the building regs Part L is worked out on a per sq m of the whole house basis and not on an energy demand basis. there is a slight relationship but not huge. This is a building reg issue, not a DEAP issue.

I have just checked through my old BERs and i have a similar example. a 250 sq m house, heat pump 351% efficiency, HRV system 90% efficiency, air tightnes q50 of 5, decent elemental u values..... and the heat pump has no trouble meeting the renewable requirement on its own.

creedp

sydthebeat wrote: »

prevented? no, but why would you not use the better values?

i know what you mean by reducing space demand, however, the renewable requirement in the building regs Part L is worked out on a per sq m of the whole house basis and not on an energy demand basis. there is a slight relationship but not huge. This is a building reg issue, not a DEAP issue.

I have just checked through my old BERs and i have a similar example. a 250 sq m house, heat pump 351% efficiency, HRV system 90% efficiency, air tightnes q50 of 5, decent elemental u values..... and the heat pump has no trouble meeting the renewable requirement on its own.

OK I see what you mean about about Part L requirement being a building reg issue. Excuse me if this is a momentously stupid Q but does that mean that for a given HP efficiency and given elemental u-values. airtightness, ect, the bigger the m2 the better for the perspective of complying with TGD L?

Im interested re your previous eg because my HP comes in a 387%, the HRV is 90%, I've specced airtightness at q50 of 4 subject to test, and my elemental u values are Roof 0.16, Walls 0.18, floors 0.14, windows 2 (although this is the value inserted by assessor, the quoted whole window u value as per window supplier is 1.3 ) for a 260m2 house. One difference
might be that we are installing a wood buring stove as a back up and this takes away 10% of the space heating demand from the more effiicent HP.
I'll take again to my BER assessor re: you eg above and see if there is anything that has been ommitted or inserted incorrectly in assessment.

Thanks very much for advice

sydthebeat

you dont need to input any secondary heating system if your main heating system can meet all your energy demands. In your case here, its suits not to have it, so i wouldnt input it.
another point... get him to input the proper window u values, 2.0 is terrible and probably very hard to even get in todays market.

so, if he inputs a proper HRV SAP Q input, proper windows, no secondary system and proper heating controls.... check again to see if it complies. id be surprised if it doesnt.

on your question, which isnt stupid at all, the Part L requirement doesnt suit larger houses as its solely based on the "per sq m" basis. However, DEAP and your rating does discriminate towards larger houses, probably due to the volume to external envelope ratio being higher for smaller dwellings.

creedp

sydthebeat wrote: »

you dont need to input any secondary heating system if your main heating system can meet all your energy demands. In your case here, its suits not to have it, so i wouldnt input it.
another point... get him to input the proper window u values, 2.0 is terrible and probably very hard to even get in todays market.

so, if he inputs a proper HRV SAP Q input, proper windows, no secondary system and proper heating controls.... check again to see if it complies. id be surprised if it doesnt.

on your question, which isnt stupid at all, the Part L requirement doesnt suit larger houses as its solely based on the "per sq m" basis. However, DEAP and your rating does discriminate towards larger houses, probably due to the volume to external envelope ratio being higher for smaller dwellings.

Thanks Sydthebeat for your help on this issue. I'll get back to my BER assessor as he seems to be insisting that I have to include the stove for purposes of assessing compliance with Part L. My understanding is that without the stove I will exceed the min requirement for renewables, even with the crappy window u-values which I will also update, which I can assure you is a great relief. Now where is my list of problems so I can start worrying about the next in line!!!

sydthebeat

creedp wrote: »

Thanks Sydthebeat for your help on this issue. I'll get back to my BER assessor as he seems to be insisting that I have to include the stove for purposes of assessing compliance with Part L.

i assume he/she will not be the one certifying compliance with building regs??

its handy if your assessor is also your certifier

creedp wrote: »

. Now where is my list of problems so I can start worrying about the next in line!!!

bring them on

creedp

Fraid not Sydthebeat! I think I said earlier on somewhere on this forum that my build would form a great foundation for a thread 'what not to do in a build'!! My engineer drew up my plans for planning and then by default my building plans and became my certifier. He never even told me he was a BER assessor and foolishly I never asked. So I sourced an assessor from the SEAI list. Suffuce it to say if there was a recommend approach to take I probably took a different approach. This is why I crop up all over this forum seeking last minute advice and solutions to problems of a chaotic and incoherent nature. All I can say is thankfully something like Boards exists as it as its many helpful and expert contributors have saved me from making even bigger mistakes on many an occasion.

sinnerboy

sydthebeat wrote: »

you dont need to input any secondary heating system if your main heating system can meet all your energy demands.

Are you sure Syd ?

From the DEAP manual Apendix A1

A secondary heating system is to be specified if: a) the main system is not sufficient in itself to heat the dwelling to the temperatures on which the DEAP is based

which accords with what you say but the sentence goes on to say

or b) fixed secondary heaters are present (e.g. a gas fire, a chimney and hearth capable of supporting an open fire or a solid fuel stove).

Now I know this is a pre build assessment so no "fixed secondary heaters are present" - but one will be in due course if creepd installs one and so one should be included.

sydthebeat

hummm, i hadnt taken heed of that one. The way i was considering it was incorrect. I was looking at the opposite, as in, when the heating system can meet demand.

Thanks SB,

sorry creepd, my bad.

I can see the dilema now.
I can see how the rating will be dragged down by the wood stove, but how is the renewable requirement dragged down?
What is the energy value without stove, and with stove?
What is the renewable input without stove and with stove?

It must be borderline at best.

creedp

sydthebeat wrote: »

hummm, i hadnt taken heed of that one. The way i was considering it was incorrect. I was looking at the opposite, as in, when the heating system can meet demand.

Thanks SB,

sorry creepd, my bad.

I can see the dilema now.
I can see how the rating will be dragged down by the wood stove, but how is the renewable requirement dragged down?
What is the energy value without stove, and with stove?
What is the renewable input without stove and with stove?

It must be borderline at best.

Damm and blast - Sinnerboy you've wrecked my day:D

I'll talk to my BER guy and get these figures

Thanks

sinnerboy

Sorry creepd I prefer to solve problems not cause them .

Try inputting the stove as a back up water heating installation too , not just for space heating , see how that pans out .

muffler

sinnerboy wrote: »

I prefer to solve problems not cause them .

Mighty

Must remember that phrase

creedp

sinnerboy wrote: »

Sorry creepd I prefer to solve problems not cause them .

Try inputting the stove as a back up water heating installation too , not just for space heating , see how that pans out .

No problem Sinnerboy. I have recoverd from my disappointment;)

One final question on the secondary heating issue - could you clarify if I got the final BER assessment carried without having installed the stove, i.e. leave the fireplace emply and temporarily block the flue, could I then avoid inputting a secondary heat source?

Thanks again

sinnerboy

The assessor can only asses what is present ....

creedp

sinnerboy wrote: »

The assessor can only asses what is present ....

Gotcha ... I won't be on-site that day:D

Thanks again

spacetherm

sinnerboy wrote: »

Is that not the point of your project exercise ? In which case ... off you go and please report back .

Attached my initial thoughts on exercise having discounted idea of investing in fabric upgrade rather than bolting on renewables to achieve equivalent of A3.

I haven't costed it yet and I don't think selling back energy to the ESB is the way to make your fortune, but if it answers the question...

hold my beer

Hi all,

Is it usual for a Council to request a BER/DEAP at the beginning of a new house build, off plans?

sydthebeat

Yes, you have to show you know how to comply with part L

A prelim part L report will do this