What BER rating do 2011 regs achieve?

lostinashford

Building to current 2011 regs what BER rating should be achieved?

No6

It should achieve an A3 rating, 2008 part L was a B1 rating.

kieranhr

The game has changed. The BER rating isn't the most stringent requirement any more. Two weeks ago I did an analysis on a house where planning was applied for in December 2011, hence part L 2011 applied. Some stats:

Natural ventilation, rads throughout, 100 mm insulation in floor, 300 in attic, 150 bead in cavity walls, 1.2 u-value for overall window units, 3 flat plate solar panels, grant condensing timber pellet boiler and room sealed stoves. The house hit a BER of A3, renewable contribution more than adequate (by a factor of 5), CO2 emissions good at about 1/3rd of allowable, but the house still failed the regs check on its overall Energy Performance Co-efficient. Basically the house was using about 50% of the energy of a 2005 standard house, whilst the 2011 regs state it needs to use no more than 40%.

Easiest route to compliance from there was to use eco-clad triple-glazing at 0.7 u-value, and install a HRV unit. Energy Performance Co-efficient was then 39%.

No6

Theres a lot of different ways to achieve the same thing, take a look at the effecct of good thermal bridging and airtightness, the notion of throwing on a few solar panels to achieve part L 2011 compliance will not work.

kieranhr

Agreed. Thermal bridging and airtightness is crucial. I have a personal preference for external insulation as opposed to cavity walls, which really eliminates a lot of cold-bridging. However, it can cost up to €12,000 more than cavity wall construction, and it's often the first thing that clients cut to get the budget right, despite its numerous advantages.
Any good contractor should be capable of hitting an airtightness value of 3 m3/m2/hr by taking care around window and door opes, etc. That's without applying airtight sealing tapes at every junction. If spending the money on airtight tapes and membranes, a blower door test of 1.5 or 2 should be achievable. But don't rely on an overly optimistic blower door target when carrying out your initial Energy assessment. If you don't hit the target on site, you've pretty much nowhere left to make up the shortfall.

kieranhr

Apologies to the OP if I'm a bit off-track there. To answer your original question, what I'm saying is - Forget about the BER, but get your house up to 2011 compliance levels, and specifically the Energy and CO2 performance coefficients. Do that, and you'll be spending no more than a few hundred euro a year on space heating and domestic hot water. Let the BER fall wherever it will.

SEVERA

kieranhr wrote: »

Agreed. Thermal bridging and airtightness is crucial. I have a personal preference for external insulation as opposed to cavity walls, which really eliminates a lot of cold-bridging. However, it can cost up to €12,000 more than cavity wall construction, and it's often the first thing that clients cut to get the budget right, despite its numerous advantages.
Any good contractor should be capable of hitting an airtightness value of 3 m3/m2/hr by taking care around window and door opes, etc. That's without applying airtight sealing tapes at every junction. If spending the money on airtight tapes and membranes, a blower door test of 1.5 or 2 should be achievable. But don't rely on an overly optimistic blower door target when carrying out your initial Energy assessment. If you don't hit the target on site, you've pretty much nowhere left to make up the shortfall.

hi i need some help here ! i am doing a provisional in accordance with (in my opinion) a very high spec but i still cant get it to pass conformity with epc/ mpepc or cpc/ mpcpc eventhough it complies with all other parts of 2011 regs. here are some details house is 114m2 dormer, 0 chimneys, 1 open flue, mvhr with fan power .70 heat exchanger 65% 0 vents, no air test done as of yet but even when i put in result of .13 a/c still no good. building fabric is excellent, floors u.12 roof u.09 sloped roof .15 windows t/g u.08 walls u.16 doors not spesified so went with u3 but even when i change to 2 little change, heating system time+temp zone control, boiler interlock,oil 94.8% usual bells and whisles 300 litre tank+stat insulated pipework, solar with dedicated 150litres went with appendix h figures as manafacturer not on spec but even when i input kingspan thermomax from harp database figures it still dont pass!! secondary heating not spec other than stove so 60% but again if i put in waterford stanley osin 78% it still wont pass!! what in the name of god do i have to do to get this to meet 2011 regs. the client wont spend on heatpump or pv etc, anyway it meets part l renewables as is just with solar tubes, so why should they have to spend a small fortune to meet this part.?? any help will be greatly appriciated.

beyondpassive

SEVERA wrote: »

hi i need some help here ! i am doing a provisional in accordance with (in my opinion) a very high spec but i still cant get it to pass conformity with epc/ mpepc or cpc/ mpcpc eventhough it complies with all other parts of 2011 regs. here are some details house is 114m2 dormer, 0 chimneys, 1 open flue, mvhr with fan power .70 heat exchanger 65% 0 vents, no air test done as of yet but even when i put in result of .13 a/c still no good. building fabric is excellent, floors u.12 roof u.09 sloped roof .15 windows t/g u.08 walls u.16 doors not spesified so went with u3 but even when i change to 2 little change, heating system time+temp zone control, boiler interlock,oil 94.8% usual bells and whisles 300 litre tank+stat insulated pipework, solar with dedicated 150litres went with appendix h figures as manafacturer not on spec but even when i input kingspan thermomax from harp database figures it still dont pass!! secondary heating not spec other than stove so 60% but again if i put in waterford stanley osin 78% it still wont pass!! what in the name of god do i have to do to get this to meet 2011 regs. the client wont spend on heatpump or pv etc, anyway it meets part l renewables as is just with solar tubes, so why should they have to spend a small fortune to meet this part.?? any help will be greatly appriciated.

1. What aperature area of solar are you using?
2. Are you using the appendix Q spreadsheet to account for solar contribution to space heating.
3. What thermal bridge factor are you inputting?
4. The windows are 0.8 overall U -Value
5. How are you getting a 0.16 wall? Is that a 225 bead filled cavity?
6 Why such a low efficiency MHRV and the open flue.

We're finding it difficult with near Passive and passivhaus houses to get 2011 compliance. With DEAP, the lower the energy demand, the more renewables are needed (sounds perverse). To address this we have sometimes done airtests with a trapdoor left open or "lost the window cert" and used single glazing values just to get compliance with the renewables obligation. In other cases we've got a dispensation from building control stating that our renewables contribution, while less than 10kwh/m2.a is 25% of heat demand. Remember the technical guidance is merely that, guidance.

kieranhr

And if I can add one additional question:

What is the area of glazing on the North elevation (or NW/NE), and how does it compare to the area of glazing on the South elevation (SW/SE)?

SEVERA

thanks i will check these and reply tonight much appreciated

SEVERA

beyondpassive wrote: »

1. What aperature area of solar are you using?
2. Are you using the appendix Q spreadsheet to account for solar contribution to space heating.
3. What thermal bridge factor are you inputting?
4. The windows are 0.8 overall U -Value
5. How are you getting a 0.16 wall? Is that a 225 bead filled cavity?
6 Why such a low efficiency MHRV and the open flue.

We're finding it difficult with near Passive and passivhaus houses to get 2011 compliance. With DEAP, the lower the energy demand, the more renewables are needed (sounds perverse). To address this we have sometimes done airtests with a trapdoor left open or "lost the window cert" and used single glazing values just to get compliance with the renewables obligation. In other cases we've got a dispensation from building control stating that our renewables contribution, while less than 10kwh/m2.a is 25% of heat demand. Remember the technical guidance is merely that, guidance.

thanks for your time in replying!
1= aperature area of 3.861 (gross 30 tubes on spec 5.3631 by default on appendix h for tubes .72)
2= apendix q speadsheet no. is this on the manual or sap appendix q ?? i just used appendix h default figures
3= .08
4= yes munster joinery t/g passiv future proof = u .8 solar transmittance .56 frame factor .72
5= 150mm cavity pumped with kingspan ecobead achieves .19 +32mm kingspan k17 insulated plasterboard on internal block leaf brings it down to .16 by my calculations ??
6= greenwood hrv1 on spec. sap appendix q figures specific fan power .70 + 65% heatexchanger. how do i enliminate the open flue when it shows a chimney in the drawing dosent a room sealed or balanced flue stove require not to use a conventional chimney but to core out independantly to the outside for its own twin wall flue pipe. i cant just tell the engineer to get rid of the chimney stack as this is the house that was granted planning permission??

thanks for your suggestions on solar and mvhr but even when i put in specific yeilds from harpdatabase and sap appendix q it still fails part L renewables is ok its just the eps cpc crack

SEVERA

kieranhr wrote: »

And if I can add one additional question:

What is the area of glazing on the North elevation (or NW/NE), and how does it compare to the area of glazing on the South elevation (SW/SE)?

thanks for your reply
the glazing totals for the ne/nw 10.23 m2
se/sw total is 10.48 m2
and velux windows is 5.86 m2
again changing anything here would effect planing permission

SEVERA

beyondpassive wrote: »

1. What aperature area of solar are you using?
2. Are you using the appendix Q spreadsheet to account for solar contribution to space heating.
3. What thermal bridge factor are you inputting?
4. The windows are 0.8 overall U -Value
5. How are you getting a 0.16 wall? Is that a 225 bead filled cavity?
6 Why such a low efficiency MHRV and the open flue.

We're finding it difficult with near Passive and passivhaus houses to get 2011 compliance. With DEAP, the lower the energy demand, the more renewables are needed (sounds perverse). To address this we have sometimes done airtests with a trapdoor left open or "lost the window cert" and used single glazing values just to get compliance with the renewables obligation. In other cases we've got a dispensation from building control stating that our renewables contribution, while less than 10kwh/m2.a is 25% of heat demand. Remember the technical guidance is merely that, guidance.

just to clarify point 2 because i dont follow you. the solar panels are only intended to provide hot water.

kieranhr

SEVERA wrote: »

the client wont spend on heatpump or pv etc, anyway it meets part l renewables as is just with solar tubes, so why should they have to spend a small fortune to meet this part.

I know this was rhetorical, but I'm going to give you the answer for your client anyway. Unless the house meets the EPC/CPC requirements, it won't comply with the building regs, hence his architect/engineer won't be able to give him a cert of compliance, and his bank won't let him draw down his mortgage.

The passive solar gain on that house is terrible, with as much north-facing as south-facing glazing. There should be 2-3 times more south glazing than north glazing. South glazing = free energy. North glazing = huge heat loss. I'm not surprised it's struggling with the EPC. But without getting too bogged down in details, what I would do myself is create a temporary file and reduce all the u-values down by half, increase the HRV efficiency and change the fuel type to timber pellet. Just to prove that it can be done, and remove that mental block. After that, I'd start cutting back again.

beyondpassive

SEVERA wrote: »

just to clarify point 2 because i dont follow you. the solar panels are only intended to provide hot water.

On point two, even in January you can make some use of your solar panels , to preheat the water going to your boiler. The solar panels might give you 20 degrees but with cold water coming back at 15 degrees and cold water coming in at 7 degrees, the solar can 'take the chill out o it, thus doing the first temperature lift in lieu of your boiler. There is an extra deap spreadsheet to calculate the benefit of this preheat when you use a large buffer tank or stratification tank. Remember underfloor runs at 36degrees, so is a good match for solar and stratification cylinder/heat store.

You'll likely need at least 40 tubes even with a large cylinder.

I wouldn't worry about the chimney, it can be done in lightweight materials. Besides, the planning system recognises that changes happen at design stage, and can be regularised by an application for the modifications.

fclauson

another question - what percentage for low energy light bulbs do you have in DEAP.
Also your MHVR at 65% is very poor and will not help

SEVERA

fclauson wrote: »

another question - what percentage for low energy light bulbs do you have in DEAP.
Also your MHVR at 65% is very poor and will not help

thanks for your reply
i have 100% low energy lighting
yes 65% is quiet low but even when i put in 85% heat exchanger efficiency it dosent do a whole lot, the funny thing is when i change from MVHR to natural ventilation with 4 passive vents the rating improves significantaly

fclauson

Can you publish the detailed report so we can all see - it sounds like something is amiss and with more data we might be able to help

sydthebeat

SEVERA wrote: »

thanks for your reply
i have 100% low energy lighting
yes 65% is quiet low but even when i put in 85% heat exchanger efficiency it dosent do a whole lot, the funny thing is when i change from MVHR to natural ventilation with 4 passive vents the rating improves significantaly

well 4 passive vents wont comply with 2010 TGD F

in my experience 2011 regs are extremely onerous to meet if choosing the old reliable of oil, solar and wood stove.

MHRV is a must if going this route.
Increase your cylinder size and obtain space heating gains as beyondpassive has stated previously. Look at 40 tubes to start with.

65% HRV is crap... pick a decent one from SAP Q
0.13 is a good air change rate, how will you confirm it will be reached?

playdoejoe

Hi beyondpassive,
can you clarify point 2 above? re appendix q;

Does the fact that water is preheated from solar factor in positively to the space heating contributions?
ie the energy that would have been used to heat the water to this temp can now be contributed to space heating by the boiler instead?
Is this not double counting?


I have had a look on the sap and seai websites for this appendix q spreadsheet but cant find it, could you provide a link please if you know where it is?

Thanks

Foiled Again

sydthebeat wrote: »

well 4 passive vents wont comply with 2010 TGD F

in my experience 2011 regs are extremely onerous to meet if choosing the old reliable of oil, solar and wood stove.

MHRV is a must if going this route.
Increase your cylinder size and obtain space heating gains as beyondpassive has stated previously. Look at 40 tubes to start with.

65% HRV is crap... pick a decent one from SAP Q
0.13 is a good air change rate, how will you confirm it will be reached?

Is it really possible to pass 2011 regs with oil, solar, woodstove and MHRV? I keep being told to go with Heat Exchange/UFHeating which I'd prefer not to.

kieranhr

Foiled Again wrote: »

Is it really possible to pass 2011 regs with oil, solar, woodstove and MHRV? I keep being told to go with Heat Exchange/UFHeating which I'd prefer not to.

Short answer Yes. You have to over-compensate in other areas.

fclauson

As I have learnt - learn DEAP and do your own maths - there are a million ways to comply and 2 million to not to

going more energy efficient does not mean comply - I am passive certified but needed PV to meet part L - dumb but true

Why was I made to spend money on eco bling just to comply with the regs !!

Foiled Again

kieranhr wrote: »

Short answer Yes. You have to over-compensate in other areas.

I just read your post No. 3 and there doesn't seem anything too extreme there. Current plan is for 150 in the floor, 150 in the walls, 150/60 in the sloping roof and 0.8 windows. MHRV, 2 acph airtightness and a condensing oil boiler feeding rads. 1 woodstove with external air supply.
Where might I be most likely to beef up?

kieranhr

Foiled Again wrote: »

I just read your post No. 3 and there doesn't seem anything too extreme there. Current plan is for 150 in the floor, 150 in the walls, 150/60 in the sloping roof and 0.8 windows. MHRV, 2 acph airtightness and a condensing oil boiler feeding rads. 1 woodstove with external air supply.
Where might I be most likely to beef up?

I'd guess that you're going to fail the renewables contribution requirement. You may need to add solar panels, or better still replace that oil boiler with timber pellet. You may have a problem with overall energy consumption, depending on ratio of north-facing glass and how good the MHRV unit is. Follow the Part L Acceptable Construction Details and you'll get down to a cold-bridging factor of 0.08, which will help a lot.

Foiled Again

kieranhr wrote: »

I'd guess that you're going to fail the renewables contribution requirement. You may need to add solar panels, or better still replace that oil boiler with timber pellet. You may have a problem with overall energy consumption, depending on ratio of north-facing glass and how good the MHRV unit is. Follow the Part L Acceptable Construction Details and you'll get down to a cold-bridging factor of 0.08, which will help a lot.

Forgot to mention Solar. I guess it needs to scale with the house size. What ballpark would be required for a 3000sqft house? EG using Tubes.

Foiled Again

kieranhr wrote: »

I'd guess that you're going to fail the renewables contribution requirement. You may need to add solar panels, or better still replace that oil boiler with timber pellet. You may have a problem with overall energy consumption, depending on ratio of north-facing glass and how good the MHRV unit is. Follow the Part L Acceptable Construction Details and you'll get down to a cold-bridging factor of 0.08, which will help a lot.

When you say Solar do you mean Thermal or PhotoVoltaics?

sydthebeat

Foiled Again wrote: »

When you say Solar do you mean Thermal or PhotoVoltaics?

Foiled again, you need to engage a BER assessor to run a provisional BER assessment on your plans and specs....

only then will you be wiser as to what you need to do to comply.

its possible to comply using ANY renewable energy... be that solar heat, photovoltices, wood burning, heat pumps, hydro, etc etc

Foiled Again

sydthebeat wrote: »

Foiled again, you need to engage a BER assessor to run a provisional BER assessment on your plans and specs....

only then will you be wiser as to what you need to do to comply.

its possible to comply using ANY renewable energy... be that solar heat, photovoltices, wood burning, heat pumps, hydro, etc etc

I am working with a BER assessor who says that with the specs given in post 24 along with Solar Thermal for 6 people I still need to get PhotoVoltaics or Wood Pellet Boiler to comply. Any other ideas other than Heat Exchangers? I don't want to go with UFHeating...

fclauson

So I consider my self a DEAP excel spread sheet expert - but I warn you I have never taken an exam or done BER training

DEAP works on a couple of base theories

a) it works out your heat loss through the fabric
b) how you will provide your energy (effects your CO2 production)
c) your renewables contribution

a - fairly easy - and there are lots of posts on how to get this down to a sensiable level -as the man said in the bar "its a u value coversation"

b - gets more tricky but getting (a) right will help with (b) - but you will have to over specify some elements of (a) to make sure you (b) (CPC etc ) faills within the numbers you need

c is a little more mad - get a really good a - a really good b and you are then stuffed with c - make the house super efficient and you will fail your renwables - why - an energy efficient house needs less energy regardless of where it comes from

So my advice - understand how to achieve a super low (a) (b) will sort of follow that as you will need to produce only a little CO2 to meet your demands

and c you have a choice
1 - put on eco bling to comply
2 - fight you building control officer - the law is very clear - DEAP is not a requirment of proof - Part L says "a resonable amount of renewables" - and the word resonable in any walk of legal life means give €€€€ to a lawyer and they will define the world resonable in a court of law for you

kieranhr

I agree with fclauson above. When you get into it, there are a lot of moving parts, maybe too many to give a simple reply on a boards.ie forum. But for me, there's a big difference between failing your renewables requirement because you haven't provided enough solar panels, and failing because your house is very well insulated. Common sense has to come into play there on the part of the certifying engineer. It's obvious that this 'failure' by super insulating will be rectified in later versions of DEAP.