BER after Solar PV

mp3guy

As part of the SEAI domestic grant, you need to have a BER done post install right?

Has anyone had their BER change from this?

graememk

mp3guy wrote: »

As part of the SEAI domestic grant, you need to have a BER done post install right?

Has anyone had their BER change from this?

The Ber will change and will get better as the "eco friendlyness " of the house will increase.

mp3guy

graememk wrote: »

The Ber will change and will get better as the "eco friendlyness " of the house will increase.

That's what I thought but I was looking for some first person accounts to get an idea of how much of change people have seen.

KCross

mp3guy wrote: »

That's what I thought but I was looking for some first person accounts to get an idea of how much of change people have seen.

It was discussed before. The BER bands are not all the same so it depends on what your starting BER rating is.

mp3guy

KCross wrote: »

It was discussed before. The BER bands are not all the same so it depends on what your starting BER rating is.

I tried searching for previous discussion but couldn't find anything, got a link?

I understand the BER scale is non-linear, so surely for a given solar power plus battery size that translates into a consistent amount of kWh/m^2/yr subtracted from your current BER?

graememk

mp3guy wrote: »

I tried searching for previous discussion but couldn't find anything, got a link?

I understand the BER scale is non-linear, so surely for a given solar power plus battery size that translates into a consistent amount of kWh/m^2/yr subtracted from your current BER?

I got a pre works BER survey done as we thought it would be touch and go that a C rating after the panels. We didnt end up going that route. but turns out we would have scraped a C3 if we got 4kwp of panels installed.. ended up with 5.6 lol

KCross

mp3guy wrote: »

I tried searching for previous discussion but couldn't find anything, got a link?

Some discussion here
https://www.boards.ie/vbulletin/showpost.php?p=112954062&postcount=110

mp3guy wrote: »

I understand the BER scale is non-linear, so surely for a given solar power plus battery size that translates into a consistent amount of kWh/m^2/yr subtracted from your current BER?

So, yes it would be a set amount that gets included in the figure but depending on the size of your house and what BER you are starting with its possible that it wouldnt improve your BER at all and conversely it could improve it by one or even two bands.... basically, it depends.

This is why you typically get a BER done before you invest in SolarPV to ensure that you will be eligible for the grant after the install.

slave1

Multiply the kW of the panels by 1.7, divide into sq meter of house and you will get a M2 energy reduction, at the range I'm looking at the gaps in the rates are 25 so for me I am at a 54M2 reduction so hoping to move up two in the rating tables

Spocker

I went from a C1 to a B2 for a 2.4KwP + 5Kw battery installed in July

Winterman1234

We install a 2.4kw pv array, no battery and went from C1 to B2, completed this February.

rx8

Mine went from D1 to B2. (4.2kwp, plus battery etc) almost a year done now.

unkel

My brutally poorly built 20 year old house was already a B5 I think (after large solar thermal install and changing all the light bulbs), that's before I changed the front door for a highly insulated composite one, added serious attic roof insulation and installed a large PV system with battery. Also replaced the kitchen extension roof to insulate it to the latest regs and replaced the plastic roof on my conservatory with a fixed insulated roof also to current regs. If I get tested again, surely I will get an A rating. Which is a bit of a joke

Edit - looked it up and I have a B3 already

It's a calculation not a measurement. Hence meaningless and at the discretion, observation and intellect of the assessor. The human is the highest liability in most systems.

mp3guy

Sir Liamalot wrote: »

It's a calculation not a measurement. Hence meaningless and at the discretion, observation and intellect of the assessor. The human is the highest liability in most systems.

Is it really that subjective? A given PV system has a nominal annual output which translates into kWh/yr. As mentioned above, normalize by your house's area and you have a value you can subtract from the total kWh/yr/m2 your home already uses, then see what bin you fall into.

A measurement is always more accurate than a calculation. Are you familar with Irish building standards? Think 19th century Scandinavia.

mp3guy

Sir Liamalot wrote: »

A measurement is always more accurate than a calculation. Are you familar with Irish building standards? Think 19th century Scandinavia.

Probably more familiar with irish building standards than 19th century Scandinavian ones in fairness.

Side note: House had BER done 7 years ago, should I get the same assessor or someone different?

graememk

mp3guy wrote: »

Probably more familiar with irish building standards than 19th century Scandinavian ones in fairness.

Side note: House had BER done 7 years ago, should I get the same assessor or someone different?

Were you happy with the last one, & has anything else changed in the house in the interim? No harm in looking for a quote

mp3guy

graememk wrote: »

Were you happy with the last one, & has anything else changed in the house in the interim? No harm in looking for a quote

Happy yes and moderate changes in the interim, before solar.

mp3guy

mp3guy wrote: »

House had BER done 7 years ago, should I get the same assessor or someone different?

If you want a box ticked it doesn't matter.



If you want a true assesment of the house's performance you have to measure it.

mp3guy

Sir Liamalot wrote: »

If you want a box ticked it doesn't matter.



If you want a true assesment of the house's performance you have to measure it.

Well that doesn't make it clear.

I have an assessment of the house's performance, I know how much energy I use in a year because I measured it myself. So in that regard, all the BER is is a box ticking exercise.

If I get the same assessor, he's familiar with the starting point and can make a relative adjustment which may be better? A new assessor might assess things differently. But what does it matter when I can calculate the kWh/m2/yr myself based on my own bills over the past year anyway. Only important for grants and planning I suppose, or selling.

mp3guy

mp3guy wrote: »

Only important for grants and planning I suppose, or selling.

Agreed.
It's a vague and relative scale that's entirely fallible.

The heating bills are more accurate but not a silver bullet either because the atmospheric conditions are variable year to year.


It's like a lottov things, doing it right is more difficult so why bother.

unkel

Sir Liamalot wrote: »

Agreed.
It's a vague and relative scale that's entirely fallible.

The heating bills are more accurate but not a silver bullet either because the atmospheric conditions are variable year to year.


It's like a lottov things, doing it right is more difficult so why bother.

And heating bills are more subjective than anything. If I lived alone in my house, my gas (heating) bill would be near zero. I would set the thermostat to no more than 17C and only in the living area. Alas there are 4 females in my household who like it a lot warmer than that

Spocker

unkel wrote: »

Alas there are 4 females in my household

Sorry for your pain :pac:

slave1

I have exact same pain, herself and three daughters, sit in tee shirt in living room when them in hoodies and blankies :rolleyes:

unkel

Spocker wrote: »

Sorry for your pain :pac:

Painfully hot

And when my mother in law (elderly) visits, the temps are cranked up to near 30C :eek:

DrPhilG

Just got my cert yesterday. Up from a C2 to a B2. Partly due to the PV installation and partly due to getting a stove in place of the open fire.

Fiver says you would have got the same rating if the flue was blocked and the solar was disconnected.

DrPhilG

Tenner says you're a blast at parties.

Easy money, here pass me the nitro glycerol willya please?

idc

Just got my BER to get grant. And the addition of 4.65 kWp, 5 kWp inverter and 5.7kWh battery moved my BER rating from a B2 to a B1 !

I had previously got a BER in February for other changes made to house, so literally the only difference was the addition of solar panels

Rzeznik

I had 2,48kWp installed in Jul. My BER after this changed from 160,35kWh/m2/yr (C1) to 125.22kWh/m2/yr (B3 - B2 is under 125... ).

Boscoirl

I have an SEAI and BER question, didnt want to start a new thread so i'll throw it in here.

Has anyone being successful in getting the SEAI grant for PV on a listed building?

Our house is a listed building, and we are looking to put in PV, we would be putting the panels on the garage roof as we cant put them on the house roof(not that we would want to)

From reading the SEAI site we need to get to a C rating to be eligible, which I think would be a tough ask for us. is there any consideration given to listed protected structures? there is reference on their site to say that they are exempt from BER, but it doesn't say it in relation to the grants.

When we bought the house,our engineer did a BER assessment for us and gave it a rating of F, and while we have done improvements since, I am not sure if it would have brought us up enough.

I have sent a mail off to SEAI to see what they say, but was just wondering if there was anyone here that went through something similar?

mp3guy

Finally got my new BER cert after having my PV installed, got a lot of insight into the process from the assessor.

Here's the background;

House built in 2005 with an 85.6% efficiency oil boiler, unknown BER at that time.

BER was B3 (147.31kWh/m2/yr) in 2013 after extra insulation was added to the attic/eaves and cavity walls pumped.

In 2019/2020 we put in a new 92.7% efficiency oil boiler, replaced two front doors with new tripled glazed ones, replaced all lights with LEDs, closed one fireplace and replaced the other with a closed solid fuel stove. My assessor told me this brought up our BER to B2 (112kWh/m2/yr).

Now the fun starts. In November I had 10.24kW of PV panels installed. Having an EV/charger/battery storage/hot water diverter is completely ignored for the BER, only the annual panel output (other rather, inverter output) is counted. Their software estimated a yield of around 8.5MWh per year.

Now, according to my assessor (who had some back and forth with SEAI on this), for energy you save in your home, you get different amounts of energy "credit". For example, if you reduce your oil usage you get some factor times that energy quantity in kWh to account for not only the lower amount of oil used, but also the transport/procurement of that oil.

For electricity from the grid, that factor is actually as high as 2x. The explanation behind this is efficiency loss from generation at a plant through substations to your home means if 1kWh of energy is made on site, by the time you use it in your home you only really get 0.5kWh.

So that means I'm credited 17MWh of energy a year, which boosted my BER all the way up to A2 (35kWh/m2/yr)!

According to my assessor and SEAI whom he asked, yes, this does mean if you bought an F-rated house and lashed dozens of panels up without doing anything else, you could drastically improve the rating.

mp3guy

mp3guy wrote: »

According to my assessor and SEAI whom he asked, yes, this does mean if you bought an F-rated house and lashed dozens of panels up without doing anything else, you could drastically improve the rating.

Is that not completely logical though, given the BER is a rating based on the energy consumption of the house, therefore if you are generating your own power to offset the power consumption, it would obviously improve the rating.

On the other hand you'd want to be crazy to do what you mentioned

mp3guy

Deleted User wrote: »

Is that not completely logical though, given the BER is a rating based on the energy consumption of the house, therefore if you are generating your own power to offset the power consumption, it would obviously improve the rating.

On the other hand you'd want to be crazy to do what you mentioned

I think it is and it isn't. BER is sometimes (perhaps wrongly) used as a proxy for how easy it is to heat a property and maintain that heat. If you're generating tonnes of electricity and using it all for your EV and have a stone cold house then the BER is misleading. On the flip side if you dump all that power into storage heaters or a load of batteries + heat pump, it'll be very representative.

This is the problem when you try to boil down everything into a single number I suppose.

slave1

Is there not a fixed formula based on square footprint of your house to work out the PV panel benefit. Panels times 1.47 divided by square meter gives energy reduction BER impact

mp3guy

slave1 wrote: »

Is there not a fixed formula based on square footprint of your house to work out the PV panel benefit. Panels times 1.47 divided by square meter gives energy reduction BER impact

I'm not sure of the specific formula, but there's no bound on the amount of energy the panels can produce, it's not capped based on your house size or anything.