EPC report

@Derek W
Appreciate the quality post.
Can an EPC assessor carry out a SAP calc? We had an extension done, with a lot of triple glazing and the building inspector is waiting for the builder to provide SAP calcs. Just thinking outside the box, maybe I can get them done at the same time as an EPC?

Wrt to the floor slab, I have seen the insulation, we have pics of it.
 
dlockers said:
Nope - it doesn't even count from what I can tell. It says floor - assumed insulated instead of floor - assumed not insulated.

Will have a proper side by side tomorrow.

Biggest impact to the score was loft insulation and led lighting, lol.

Path to c/b is solar or external wall insulation
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Loft insulation and LEDs are two very easy and cost effective improvements. Though I'm thinking of leaving the loft insulation at 100mm to begin with and may add more in the future depending how comfortable the rooms feel. The biggest gains in thermal performance are taking it from 0mm to 100mm. Then rapidly diminishing returns after that.
 
Macky said:
Loft insulation and LEDs are two very easy and cost effective improvements. Though I'm thinking of leaving the loft insulation at 100mm to begin with and may add more in the future depending how comfortable the rooms feel. The biggest gains in thermal performance are taking it from 0mm to 100mm. Then rapidly diminishing returns after that.
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Can't comment as I went right to 270mm. Make a huge difference
 
NoNameNoNumber said:
@Derek W
Appreciate the quality post.
Can an EPC assessor carry out a SAP calc? We had an extension done, with a lot of triple glazing and the building inspector is waiting for the builder to provide SAP calcs. Just thinking outside the box, maybe I can get them done at the same time as an EPC?

Wrt to the floor slab, I have seen the insulation, we have pics of it.
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I'm slightly thrown here only because when we do an extension typically its just a set of U-Values for each element that we need to provide rather than a SAP Calculation because the SAPs calcs are based on current regulations so i can say with confidence that they would fail when the existing part of the property is being assessed. When there's an excess of glazing in an extension we have to do a compensatory calculation to ensure it can better the notional calculation with 25% of the floor area max glazing. To produce the EPC though, a reduced data SAP or RdSAP as mentioned in my previous post would have to be carried out so you can ask for a copy of it to be provided to the building inspector.

Macky said:
The biggest gains in thermal performance are taking it from 0mm to 100mm. Then rapidly diminishing returns after that.
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That's a sort of correct / incorrect way of looking at it. I'll give an example off the top of my head so figures won't be as accurate as they could be. If i use a wall as example instead of the roof and the Scottish standards since those are the ones I'm used to working with it'll be easier for me. If we take a 600 mm thick stone wall with lath and plaster internally the U-Value will be around 1.7W/m2K or worse. If we add in a timber frame / metal frame around the wall internally and add 100 mm glasswool our U-Value will probably be around 0.33W/m2K The current standard for a new wall in Scotland is 0.17W/m2K so your statement is correct there is a massive improvement with just 100 mm insulation but you've got to improve it by half again to meet the current standard. The same principal applies to the roof. Up here we've got to meet values of 0.12W/m2K which equates to arround 400 mm insulation so 4 times the amount you've put in. The downside is that as you wrap your house up if the heat builds up (summer over heating) then you've got to figure out a way to remove that heat without having to overly rely on air conditioning as the boiler usage you're saving in winter with a better insulated home will just go on the power required to cool your building.

As I mentioned in my last post the goal of passive house / net zero requires little heating or cooling as a house will have to be designed to perform with high insulation envelope and a way to minimise heat build up during the summer by use of pergola / brise soleil or shutters to block the high intensity sun for most of the day but still allow solar gain when the sun is lower during winter.

EDIT

Also 25% of a homes heat is lost through the roof so thats why its predominently the best insulated.
 
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Thanks for the analysis! I'd need to spend another couple of hundred quid to bring it up to 270mm which I suppose over the many years we'll be in this house is practically nothing.
 
EPC is back.
Previous score / potential was 64/76

New one is 72/80

Couple of points I find odd.
1) Air source heat pump is only ‘good’
2) ASHP provides hot water, immersion for legionella cycle. They’ve written ‘HW is via immersion -average’
3) recommended zoned heating control. AFAIK that was an inefficient way to control an ASHP
4) Recommended 2.7kWp solar. We already have 6.7kWp.
5) No acknowledgement of the huge triple glazed panels we now have. Just ‘fully double glazed -good’
6) ‘ Main heating- underfloor, electric - good’. We have 80m^2 of wet UFH downstairs and 2m^2 of electric UFH in the en suite. Not a main heat source.

Whilst I accept it doesn’t really matter, this guy has annoyed me!
Let me know your thoughts as to whether I’m being reasonable or not before I contact them please :)
 
NoNameNoNumber said:
All correct as in you agree they’re valid points that I should raise with the assessor?
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I just don't think people care that much about EPC scores when buying houses? It's an indicative, back of fag packet calculation by a person on near minimum wage who's likely visiting another ten properties that day. I'd just move on and forget about it, personally.
 
It’s up to you but in principle, you paid for an EPC which is wrong.

Even if it doesn’t change the score, it’s whether you are happy to pay for someone doing a **** job or not.

One trend I have seen is that assessors have a habit of just copying the last one for things they can’t see. So if it’s wrong now, it’s likely to carry forward unless someone points it out to them.

For example, a couple of EPCs I saw for the house I am in assumed no floor insulation despite it being built a decade after floor insulation had been required for building regs.
 
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Isn't it already an A? I would ignore. Not like you can improve the grade. I believe they're changing EPC to something different soon anyways
 
Macky said:
I just don't think people care that much about EPC scores when buying houses? It's an indicative, back of fag packet calculation by a person on near minimum wage who's likely visiting another ten properties that day. I'd just move on and forget about it, personally.
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www.rightmove.co.uk

Sellers of homes with improved EPC ratings see 'green price premium' | Property news

A home's EPC rating improving from an F to a C could increase the value by an average of 15%, or almost £56,000.
www.rightmove.co.uk www.rightmove.co.uk

People do care but it is subject to some diminishing returns as you move up the scale.
 
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Jokester said:
In Scotland it will be a requirement to be EPC C or better to sell your house in the near future (2032 I think), England I think was talking about doing the same thing, not sure if it’s in law yet.
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Until this happens, absolutely no benefit to you really, other than cheaper energy bills, after it's made up for the cost of all the upgrades anyway.
 
The house I'm buying is 77 C with potential for 84 B. Only recommendations are solar panels and water heating.

It says loft insulation is 200mm so not bad. 75% low enery lighting, I will make sure it's 100% if it isn't already.
 
NoNameNoNumber said:
EPC is back.
Previous score / potential was 64/76

New one is 72/80

Couple of points I find odd.
1) Air source heat pump is only ‘good’
2) ASHP provides hot water, immersion for legionella cycle. They’ve written ‘HW is via immersion -average’
3) recommended zoned heating control. AFAIK that was an inefficient way to control an ASHP
4) Recommended 2.7kWp solar. We already have 6.7kWp.
5) No acknowledgement of the huge triple glazed panels we now have. Just ‘fully double glazed -good’
6) ‘ Main heating- underfloor, electric - good’. We have 80m^2 of wet UFH downstairs and 2m^2 of electric UFH in the en suite. Not a main heat source.

Whilst I accept it doesn’t really matter, this guy has annoyed me!
Let me know your thoughts as to whether I’m being reasonable or not before I contact them please :)
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As before all my responses are on the basis of my new build knowledge but the data entry should be similar.

1. I've found if you insulate to the standards and heat with a heat pump the base rating will be C as mentioned above a new build SAP Calculation the heat source is based against an Air Source Heat Pump so the efficiency gains will be relatively low but as stated is good. I'll surmise that under an older calculation package it was probably rated as very good or excellent.
2. No real comment here.
3. I'll guess that your property is over 150m2? The calculation package has a cut off point where you have to have 'time and temperature zone controls' for your heating system. Typically on a two storey dwelling you'd have one zone as the ground floor and one on the first floor. The ground floor would typically be a degree or two warmer than the first. On a bungalow you'd maybe have one zone set as the public rooms and one zone with the private zones. How practically that can be done on an existing house, I'm not too sure.
4. I'd call this one out as he's not allowed for something that you've already got fitted so should improve your EPC and would take that recommendation off for future improvements.
5. Are all your windows now triple glazed? He may have just put in the worst case scenario if you've got some double glazing although on the new build stuff you can define every glazed element so he may be able to split some glazing into double some triple. Again this may have been laziness on his part.
6. This will probably refer to the main heating type being the underfloor heating (radiators predominantly at first floor?) but the electric part of it is because its being powered by the heat pump and not as youre possibly thinking that the En Suite heating is powering your house! :p


dlockers said:
Isn't it already an A? I would ignore. Not like you can improve the grade. I believe they're changing EPC to something different soon anyways
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The 72/80 is the new EPC rating first with the potential listed second if he implements the changes. 82/83 is the cut off for a B rating then the A rating from memory is around 96/97 with the top rating at 120! Don't ask!
 
After a little back and forth with the assessor they have amended my report.
Now a B 87 with a B 91 being possible if I were to have zoned heating control for the heat pump and solar diverter for domestic hot.

I still disagree with the zoning, as do Heat Geeks but the EPC guidelines say I should be zoned.

Also, somehow we’re producing 2.1t of CO2.

They still have my domestic hot listed as immersion- off peak. Like I’ve stated several times, it is heated by the heat pump, the immersion is for legionella cycle only.
 
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