Improving upon BER Rating

D

DublinHead54

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Hi,

I am looking for advise on if it is possible to get to a B3 BER rating to avail of a 'green' mortgage based on work done to date. The house purchased last year had a BER rating F 392.98 (kWh/m2/yr) and to achieve a B3 it needs to be 125 (kWh/m2/yr). The house is a 1950s semi d with suspended floors, garage attached, no insulation in cavities and think the back wall is poured concrete.

I have done the following works since purchase

1. Replaced flooring - laid laminate throughout downstairs on top of boards with best quality insulation and put a plastic film between floor and floorboards to reduce draft
2. Replaced old wooden front door with a composite door (A rated)
3. Replaced old french door with sliding door (A rated)
4. Installed TRVs on all radiators, plus a few new radiators
5. Replaced hot water tank with insulated copper tank
6. Installed 3 zone heating controls (upstairs / downstairs + hot water)
7. Insulated Attic (spray foam)

TBD
1. Windows - Replace existing double glazing wiht A rated / Triple glazing.

There are two open fires, if I just block these will that benefit or do I need to replace with a stove / electric fire? I am not planning on wrapping the house or dry lining.

Is it possible to get to a B3 with the above?
 
It most certainly should be, but it won't with the 2 fireplaces. Where in the attic did you use foam insulation? How warm/snug does the house feel since you did all that work?
 
Take a look at this doc and identify your house type. 1950s semi-d is likely to resemble that on page 38. Note to get to a C3 they recommend wall insulation. Hard to see you getting to B3 without that. Also, what efficiency is your boiler?

Was the spray foam in the attic certified and what u value did it achieve?
 
noproblem said:
It most certainly should be, but it won't with the 2 fireplaces. Where in the attic did you use foam insulation? How warm/snug does the house feel since you did all that work?
Click to expand...

Between rafters and slates. Well I only moved in in April and insulation was done in July, so not really had very cold weather. I would say the house is holding 1-2 degrees warmer now post attic insulation. What to do with the 2 fireplaces? I was considering just blocking them in the interim with a balloon. Currently they are gas fires, but don't believe I've the right ventilation for them.


I've looked at that document thanks. I'm not sure on the boiler, but assume it is pretty good as it was replaced by the previous owner in 2018. I don't know on the attic to be honest, I used a reputable company but can't remember the U-Value.
 
"Is it possible to get to a B3 with the above?"
Nobody can tell you this without knowing a lot more info. Maybe ask a ber assessor to do the calcs. But, as alluded to by Leo above, I would guess not a hope of B3 based on what you've done to date.

Btw, "A" rated windows and doors are a marketing gimmick, meaningless.

Do you have all documentation to support the works completed to date as this is needed for the measures to be accepted & included in the BER calculation by the assessor.

A bit off topic but if it were my house, I would ignore the 'green' mortgage idea and concentrate on improving my house's performance based on what is actually happening wrt heat loss rather than an arbitrary box ticking exercise which churns out a rather meaningless BER result. My main aim would be to have a comfortable, healthy & affordable to heat house.
 
How is the house ventilated now? What's your ventilation strategy moving forward? Those open fires (aka passive stack ventilators) might be important for moisture control especially if other natural ventilation channels have being reduced .... heating (heat loss) / ventilation / moisture load need to be considered systematically rather than in isolation
 

Thanks for the input. The context regarding the green mortage is I am coming off the initial mortgage rate and saw that there is a further 0.2% discount on the mortgage if I have a B3. I am evaluating whether what I have done / plan to do is worth getting a BER assessment or not. I am focused on having a comfortable house, and personally I think the wrap / internal insulation is overkill considering the cost at the minute to do in isolation.

I don't know how I should describe the new doors and windows if not A rated to convey they are much better than the wooden door with the gap at the bottom previously! What documentation do I need for the replacement of a door?

Regarding ventilation, there are suspended floors with ventilation underneath, but no in room wall ventilation which I understand is now mandatory when having an open fire?

Who can assess whether my house is properly ventilated?
 
I'd take a step back and consider the following;

1. What is 0.2% worth to you in today's terms over the mortgage term, will it cover the cost outlay of achieving a B3?
2. As mentioned above, if the walls are not insulated the chances of achieving B3 from an initial F rating is very low - especially with 2 chimneys.
3. Do you use both chimneys for open fires (these will not help your rating), if not then suggest blocking them up & adding wall ventilation to both rooms.
4. All of the measures you've taken so far are of little help if 75% of your external walls (semi-d) are not insulated as circa 35% of heat loss occurs here.
 
If focusing on a comfortable home then you might be better off getting an air leakage test or heat loss survey done to understand what's going on rather than a ber assessment. One of the results os such a survey would be a recommendation on how best to ventilate too.

Doors. /windows should be described by their certified specifications such as U & g values, frame thermal breaks, plus ratio of glazing to frame area and most importantly how well they will be installed/air tightened (you can have the best of the best windows rendered useless if installed poorly).

The ventilation under your suspended floors is completely separate to what I was referring to. All fossil fuel burning appliances require appropriate dedicated ventilation but also appropriate ventilation is required for the exhaustion of water vapour from the dwelling during the heating season. An imbalance in this ventilation can easily lead to poor indoor air quality plus mildew / mould etc. Thread carefully and don't create one problem by trying to fix another one.
 
bren1916 said:
4. All of the measures you've taken so far are of little help if 75% of your external walls (semi-d) are not insulated as circa 35% of heat loss occurs here.
Click to expand...

I wouldn't say completely useless as one of the most effective insulation options is the attic.


I see options for a thermal imaging test or heat less test (air blower). I am concerned about ventilation as I have noticed if the bedroom doot is closed at night there is condensation on the inside of the window in the morning. Not sure if this is due to the old windows or just a lack of ventilation in the room.
 
Dublinbay12 said:
I am concerned about ventilation as I have noticed if the bedroom doot is closed at night there is condensation on the inside of the window in the morning. Not sure if this is due to the old windows or just a lack of ventilation in the room.
Click to expand...
If the condensation reduces to nothing over the next few weeks then nothing to worry about (your house is drying out after the summer) but if it persists then it's a sign of an imbalance.
 
You can borrow an energy saving kit from your local library which contains heat imager, hygrometer for moisture, device to check power being drawn at any plug outlet etc. Funded by SEAI via an EU project. And they were too mean to put in a proper heat imaging camera but the devices they've supplied are still ok at finding problems once you approach it systematically. And it's free.
 
For my 1990s semi-D I replaced original windows with high-quality alu-clad ones with a low U value. I also replaced the original boiler (60% efficiency) with a modern one.

I moved up only from a BER D2 to D1.

This is purely anecdotal of course, but leads me to think that these improvements are not easy to achieve. the BER assessor said at the end of the day I had external walls on three sides and there was nothing I could do about that!


I looked at CSO data for pre-1977 semi-Ds with mains gas supply. In 2021 319 of them got a BER B3 or above out of a total of 2,229. Of that 319, 202 were a B3, and only 2 got an A2 (none got an A1). Clearly not impossible, but also not very common either.
 
Solar PV has a massive impact on BER. You can get a small system for quite reasonable money now - €2,400 spread over ten years.
 
We went c1 to b2 with the addition of Solar PV.
When we bought the house it was D1 (80s semi) - upgrades from d1 to c1 included upgraded boiler with zoned heating, attic insulation, draught lobby on porch. Windows also done but I think they had minimal impact.
 
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