Typical BER improvement after solar pv install

Colm82 · 08-06-2021 6:36am #1

Could anyone give me a rough idea on what my BER would improve by on installation of solar pv. Thinking of getting a 4.2 kW SYSTEM not 100% certain on a battery yet-would a battery change the ber?

My current BER is D2, house is a 125sqm bungalow, I want to ensure it would increase into the C category for the grant before I start the process.

Much appreciated.

Rigor Mortis · 08-06-2021 8:30am

I went from a D1 to a C2. That was with 14 panels and a battery. I dont know the difference that a different system would make

slave1 · 08-06-2021 1:58pm

Colm82 wrote: »

Could anyone give me a rough idea on what my BER would improve by on installation of solar pv. Thinking of getting a 4.2 kW SYSTEM not 100% certain on a battery yet-would a battery change the ber?

My current BER is D2, house is a 125sqm bungalow, I want to ensure it would increase into the C category for the grant before I start the process.

Much appreciated.

Battery is irrelevant.
Your BER will improve by 4,200W x (BER Factor) 1.47 = 6,174kWh "energy reduction" per annum.
Divide this into your sqM....6,174kWh / 125 = 49.4

This 49.4 is your energy reduction per M2 and should be taken off your current rating to see the improvement.

If you are D2 then you are at least 260kWh/M2 so taking 49 off leaves you at 211kWh/M2 which puts you into a C3 rating.
You could also be at the high end of the D2 in which case you won't make a C3 rating e.g. 299-49=250=D1

Remember your BER rating was based upon calculations at the time it was carried out, they may have changed so there's no guarantee the above will stand as your entire BER house calculation will fall into calculation criteria at time of assessment

Bobeagleburger · 08-06-2021 3:24pm

^^

That calculation may be incorrect.

Let me find the one someone on the BER forum gave me last week.

Bobeagleburger · 08-06-2021 3:29pm

see appendix m here

https://www.seai.ie/home-energy/building-energy-rating-ber/support-for-ber-assessors/domestic-ber-resources/deap4-software/DEAP-Manual-Version-.pdf

The electricity produced by the PV module in kWh/year is
0.80 × kWp × S × ZPV (M1)

where:

S is the annual solar radiation from Table H2 (depending on orientation and pitch)
ZPV is the overshading factor from Table H3. If there are two PV modules, e.g. at different tilt or orientation, apply
equation (M1) to each and sum the annual electricity generation.

So, in the example above for the OP, this would be:

(0.80 × 4.2kwp× 1 × 1072) / (125 m2)

= 28.82 energy reduction per m2

Note, this example assumes no shading and uses a South facing roof with 45 degrees pitch....

SD_DRACULA · 08-06-2021 3:44pm

Yeah as mentioned above the annual production is the biggest factor, mine went from C2 to A2 with 7kwp because of the total annual production, or so I was told.

kabakuyu · 08-06-2021 4:08pm

I just completed a first time Ber for grant.I installed a 2.5 system south facing. I had other energy improvements carried out in the last few years (new condensing boiler,trvs on rads,and new double glazing).
I also recently topped up attic insulation by 200mm, permanently blocked 2 fireplaces,relagged immersion,installed LEd lights everywhere,and did other little jobs myself to ensure I hit the c3 for the grant.I ended up with a b2 which I was very happy with.
I had all the documentation for the windows and kept specs for lagging jacket,leds, insulation, and anything else I could think of.I suggest you do all the small jobs to ensure you hit the c3.

Zzippy · 08-06-2021 4:49pm

6 wrote: »

see appendix m here

https://www.seai.ie/home-energy/buil...l-Version-.pdf

The electricity produced by the PV module in kWh/year is
0.80 × kWp × S × ZPV (M1)

where:

S is the annual solar radiation from Table H2 (depending on orientation and pitch)
ZPV is the overshading factor from Table H3. If there are two PV modules, e.g. at different tilt or orientation, apply
equation (M1) to each and sum the annual electricity generation.

So, in the example above for the OP, this would be:

(0.80 × 4.2kwp× 1 × 1072) / (125 m2)

= 28.82 energy reduction per m2

Note, this example assumes no shading and uses a South facing roof with 45 degrees pitch....

Dead link on SEAI website. Any chance of a screenshot of that appendix?

Bobeagleburger · 08-06-2021 5:02pm

Zzippy wrote: »

Dead link on SEAI website. Any chance of a screenshot of that appendix?

Link updated

https://www.seai.ie/home-energy/building-energy-rating-ber/support-for-ber-assessors/domestic-ber-resources/deap4-software/DEAP-Manual-Version-.pdf

Colm82 · 08-06-2021 7:53pm

Guys thanks to all who have responded - my current rating is at a usage of 269 kW/m2 so a reduction of 29 won't bring me to a C.

Also my house is south east facing so likely wouldn't get the full 29 reduction from solar pv.

I am planning on upgrading the hwc as its an old copper one with a very basic lagging jacket and possibly new windows which may improve this further as we are doing a renovation job on the house. Although this is just replacing old brown double glazing with new white double glazing which is more for aesthetics than energy efficiency so may not improve anything.

I also plan also to block off our three open chimneys during the renovation (two open fireplaces and a solid fuel stove) and replace all with a single modern wood pellet Burner with an external flue out of the gable wall and new rads with tcv.

Hopefully all works together may bring me to a C.

Do any of the solar companies assess the final Ber before work so you would know final rating post works?

Colm82 · 08-06-2021 7:55pm

kabakuyu wrote: »

I just completed a first time Ber for grant.I installed a 2.5 system south facing. I had other energy improvements carried out in the last few years (new condensing boiler,trvs on rads,and new double glazing).
I also recently topped up attic insulation by 200mm, permanently blocked 2 fireplaces,relagged immersion,installed LEd lights everywhere,and did other little jobs myself to ensure I hit the c3 for the grant.I ended up with a b2 which I was very happy with.
I had all the documentation for the windows and kept specs for lagging jacket,leds, insulation, and anything else I could think of.I suggest you do all the small jobs to ensure you hit the c3.

Thanks - great advice and lots of information very relevant for my future works.

carrickbawn · 18-06-2021 7:56am

Have recently had Solar PV fitted and am long overdue changing my electricity provider. Do I need to tell them about PV and what should I be prioritizing now from the new provider.
TIA.

SouthWesterly · 18-06-2021 10:05am

Colm82 wrote: »

Thanks - great advice and lots of information very relevant for my future works.

I was the same.
My house was a d2. I did some work on the house and a new oil boiler.
Looked after the likes of bulbs, adjustable vents and door strips. It went to C1. I've just to get the solar in now and add the new figures for the assessor to send in the submission.

Bobeagleburger · 18-06-2021 10:16am

went from C1 to A3 with:

Attic insulatution topup
Cavity wall pumping
5.7kwp pv system

pv system alone moved it 3 grades.

KCross · 18-06-2021 10:40am

carrickbawn wrote: »

Have recently had Solar PV fitted and am long overdue changing my electricity provider. Do I need to tell them about PV and what should I be prioritizing now from the new provider.
TIA.

Do you need to tell them... no
Prioritising... cheapest electricity possible please!

KCross · 18-06-2021 10:42am

6 wrote: »

went from C1 to A3 with:
Attic insulatution topup

Cavity wall pumping

5.7kwp pv system

pv system alone moved it 3 grades.

Just so others don’t get misled, the grades are not linear so you won’t get moved up 3 grades in every case. It depends on what grade you’re starting from.

raytaxi · 18-06-2021 10:43am

Mine has gone from a B3 (143.47) to a B2 (118.9) with a 2.5kwp, though first was a DEAP 3.2.1 new one done under latest DEAP 4.0 don't know if that would have any bearing and unfortunately I was not home when it was done.

Bobeagleburger · 18-06-2021 10:45am

KCross wrote: »

Just so others don’t get misled, the grades are not linear so you won’t get moved up 3 grades in every case. It depends on what grade you’re starting from.

Absolutely.

Plenty of variables to be considered.

deravarra · 18-06-2021 4:32pm

After stumbling upon this post, I think my C3 rating should come up a bit after all we have done and will do:

Done:
new boiler - went to grant vortex condensing.
New smart heating controls.
New efficient water cylinder.
Wood pellet room heating stove.

Being done soon:
Composite door replacing old wooden door.
Solar PV including eddi diverter (5kwph)

I would be hoping all this should bring us up a good bit!

slave1 · 18-06-2021 6:51pm

The EDDI will not feature in any BER calculations but 100% they are worth it

deravarra · 18-06-2021 8:06pm

slave1 wrote: »

The EDDI will not feature in any BER calculations but 100% they are worth it

I am hoping the other bits and pieces will drag it up to a better rating

AndyBoBandy · 23-09-2021 9:41am

We bought our house as a C3, and have since done the following work;

Attic converted and insulated, originally it was the roll up stuff just laid out above the existing ceilings, now it's the foam boards in the roof and side walls (so I presume an upgrade on what was put in 15 years prior when the house was built), then the removed/remaining roll up stuff was packed under the floor above the ceilings outside of the attic walls.

Heating control - old analogue timer replaced by Nest smart thermostat

Open gas fire replaced by inset stove which now seals off the chimney to the outside - not sure if this will affect BER, but it sealed up a terrible draught in the sitting room.

Wooden front door replaced by composite front door (original door was draughty, new door is 100% sealed).

Lighting - 99% of lights in the house are LED (Philips Hue). Only non LED bulbs are the cooker cover lights and under kitchen unit lights, which are rarely used.

Hot water tank: when the attic was converted, the hot press needed moving, so I replaced the old ~60L copper tank with a factory insulated 162L stainless tank.

Upcoming work;

Solar PV install - anything from 4.7kW - 5.8kW (depending on what they can fit on the roof, but the more the merrier), battery, Eddi

Not sure what the existing work, and PV work will do to the BER, but would be delighted if we could get up to a C1, and we'd be over the moon if we could get it into B territory!!

Future work we'd like to do is install an Air to Water Heat Pump, and then possibly upgrade the windows to triple glazed, but that's probably a few years away yet.

slave1 · 23-09-2021 10:09am

Hope you kept receipts! Depending on the BER assessor they can be quite bitchy, luckily I keep photos of everything so could "show" hidden improvements like floor insulation, insulated slabs etc.

1974 typical semi now with B2 but should be A3 due to SEAI not accepting my oil boiler efficiency and also extra panels installed since BER carried out

AndyBoBandy · 23-09-2021 10:23am

Thankfully I have the receipts for every and all purchases I've made for the house including stove, hot water cylinder, front door etc...

I also extensively photographed every step of the the attic conversion...

I even put additional pipe insulation on the (warm) piping to/from the new cylinder.. as I wasn't happy with it being left bare..

Biker1 · 23-09-2021 12:56pm

https://www.boards.ie/discussion/comment/117927864#Comment_117927864

An assessor has to provide definitive proof for all entries into DEAP, based on SEAI's requirements for same. They are on a penalty point system which can lead to cancellation of their registration if 10 penalty points are accumulated over a two year period. Perhaps some assessors have another full time income and are willing to take shortcuts but most don't and are not being bitchy by trying to stay in business.

slave1 · 23-09-2021 1:26pm

I've heard of assessors who won't take photos as they don't want the "hassle" associated with off-paper proof, in my own case my assessor did take photos and did work with them.

Where he failed was my oil burner, it had a hard coded efficiency percentile which put it below the 86% (which is a big reduction of your BER rating), I have the boiler serviced every year and have all my effieciency readings from professional boiler service guy and I've never been below 86%, despite pure documentated proof the SEAI side would not back down and "forced" a below 86% efficiency. BER guy was fed up and wouldn't "fight" the case so I just paid him and left it at that.

samdeluxjones · 24-09-2021 9:50am

I have PV system in 5 months now but no grant as my house is less than 10 years old so didn't need to get BER.

Is there any reason I might have to get a BER in the future as in for the feed in tariff if it ever comes?

graememk · 24-09-2021 10:07am

https://www.boards.ie/discussion/comment/117932020#Comment_117932020

Unless you're selling your house, no.

The proposed premium rate, that might need a ber would only be for new installs. Anyone else will just get the standard rate.

Dag12 · 25-04-2022 12:53pm

I bought a house with C1 rating that was build in 2008. Previous owner had a BER assessment done. Which suggested upgrading gas boiler to >90% efficiency one; upgrading attic insulation to 300mm and adding heating controls via thermostat.

Upgrading gas boiler alone was going to bring up the BER rating to B3.

Now the question is how much BER increase should I expect if I add solar PV?

I would appreciate your thoughts on this.

AndyBoBandy · 25-04-2022 1:45pm

I went from C3 when we moved in to B3 post solar, but I did do other things listed below that helped the rating (just missed out on B2 by a few points).

We installed a 5.78kWp & a 5kWh battery system

Attic converted and insulated

Heating control - old analogue timer replaced by Nest smart thermostat

Open gas fire replaced by inset stove

Wooden front door replaced by composite front door

Lighting - 99% of lights in the house are LED

Hot water tank: replaced the old ~60L copper tank with a factory insulated 162L stainless tank - Eddi diverter also installed with the solar system.

ECO_Mental · 24-05-2022 10:29pm

I'm a bit nervous posting this here as to be honest I am a but shocked myself at the result of my BER for my new build house A1 with a negative energy demand of -3kWh/m2/year....I'm posting it here because my provisional BER was an A2 and that didn't have any Solar PV in the calcs. I also had a wood stove in the Part L calcs and I don't have any stove or fire place in the actual build.

The only real difference from the Part L to what was actually built was the 6.1 kWp of solar PV (and no stove) so this is what I am guessing is giving me this result. Only got this from my assessor this evening so have not had a chance to chat to him about it.

But I am more than happy...It was not a goal of ours to get an A1 just to build the house to NZEB and follow the current specifications if not a bit better. I am sure its the PV that is making the big difference here

The main fabric of my house

Kore Passive Foundation

200mm pumped cavity

Triple glazed AluClad windows

Air to Water Heat pump

MHRV

6.1 kWp Solar PV

Underfloor heating upstairs and downstairs (each room has its own zone)

Air tightness of 2.4 (I think its actually a bit better as I replaced one or two seals on a sliding door since that were the letting in a small draft)

Typical BER improvement after solar pv install

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