Getting an "A" EPC Rating

Alnat1

How long until you get ROI on what you've spent? Has the property value increased to reflect the cost?

Screwdriva

Alnat1 said:

Has the property value increased to reflect the cost?

Hard to say. Based on the report that came back, the value has risen exponentially but I don't believe the improvements were the sole driver for this. 

Martyn1981

Screwdriva said:

Martyn1981 said:

We got one done for our second install in 2012, scored a very high B, with a low A potential if we had CWI and underfloor insulation. We actually already had both, but couldn't prove it. I've often commented that it's somewhat ridiculous that our typical 1930's 3-bed semi, can score that high. It's a bit of an insult to the incredibly efficient builds that some have achieved, whereas ours 'sneaks' in using the PV bonus, which doesn't improve efficiency, but does (as I understand it) reduce our net CO2 impact, which is great, but I'm not sure it's an apples to apples comparison.

Slapping Solar PV on your roof won't get you an A rating. This is why none exist (yet) that the surveying company knows about, as the EPC scoring system makes it next to impossible to "sneak" an A in. For instance, not having triple glazed windows everywhere would have lost us the score. 270mm of loft insulation is great but you need insulation in between the roof rafters as well. Same with 50mm of floor insulation. Relatively easy to skip any of these types of improvements and most people do.

We have a couple of newspaper journalists coming to write about the relatively inexpensive nature of the retrofit compared to the efficient (read: costly) builds you mention. I hope they can find other examples that are more deserving of the attention.

Sorry, but as I said, we 'got' an A if the CWI and underfloor insulation had been accounted for.

Our score is a B84, suggested potential is A98, the CWI would take it to A92, floor insulation to A93, and draught proofing to A95. TBF draught proofing has been addressed since it reflected the leaky original wooden front door and leaded glass, which couldn't be upgraded, and we didn't want to replace, so we added a large DG glass porch instead.

As I said, I don't believe our house should be rated that high, it's piggybacking off the PV. Not anything to be concerned about, I just don't feel it reflects fairly on those who've managed to almost eliminate heating needs, which we haven't.

Nothing we've done is exceptional, all local 1930's semi's could do the same, and reap the benefits we have. I'm simply saying that I personally can't claim anything 'special' as the sneaky PV (a quite large system at the time) benefits us.

Screwdriva

Martyn1981 said:

Sorry, but as I said, we 'got' an A if the CWI and underfloor insulation had been accounted for.

Our score is a B84, suggested potential is A98, the CWI would take it to A92, floor insulation to A93, and draught proofing to A95. TBF draught proofing has been addressed since it reflected the leaky original wooden front door and leaded glass, which couldn't be upgraded, and we didn't want to replace, so we added a large DG glass porch instead.

As I said, I don't believe our house should be rated that high, it's piggybacking off the PV. Not anything to be concerned about, I just don't feel it reflects fairly on those who've managed to almost eliminate heating needs, which we haven't.

Nothing we've done is exceptional, all local 1930's semi's could do the same, and reap the benefits we have. I'm simply saying that I personally can't claim anything 'special' as the sneaky PV (a quite large system at the time) benefits us.

I don't dispute your actual or potential ratings. And yet, the fact remains that no other A retrofit currently exist in the London area (that our assessor was able to locate on their EPC database). 

I also don't believe anyone actually believes that a Passive Haus should be compared to an A EPC rated retrofit (this may be why they have watered down their own standards for the "EnerPHit" retrofit certification.) I think the point the London Authority is trying to emphasize is exactly the point you make i.e. that all homes can and should upgrade (relatively easily) to achieve this highest rating for energy performance.

There will eventually be a ceiling to what an older property can achieve but the vast majority of homes are nowhere near it, for one reason or another. 

ABrass

By underfloor insulation, was that the XPS stuff you used for the UFH? If memory serves it was 25mm XPS boards with the usual channel for the 16mm pipe to pop into.

Was there more than that underneath? Because I'm surprised that was considered good enough for the EPC.

EPC and BR aren't connected to each other, but for Building regs you're supposed to try to hit a U value of 0.25 for a refurb which needs around 70mm PIR or around 100mm XPS. Double that for new builds.

10mm of XPS is comparable to thick carpet.

zeupater

Hi

We're pretty much what would be classified as a 'retrofit' property with a high B rating of 87, with potential of 90 (not in London though), which doesn't really reflect the efficiency measures employed due to the simplified EPC rating evaluation scheme not recognising a number of measures have or the atypical efficiency build for a house typical of the year banding in which it's included ...

For example, the 'potential' of 90 is based on installing underfloor insulation ... that would be insulation which is already there (pumice thermal layer in concrete slab) that the assessor was made aware of but wouldn't/couldn't take the time to confirm it's existence with 'photographic proof' (despite an offer to lift a portion of flooring/carpet) and therefore ticking the 'assumed none' box.

... originally the cavity wall 'assumed none' box was also going to be ticked due to there being no sign of injection for 'photographic proof' - fortunately there is a spot in one of our lofts where roof structure is supported by a wall where the original cavity insulation is visible and 'photographic proof' could be included ...

... other pretty major issues included the omission of our multi-fuel stove as the main heat source (which it was by kWh.t/year) because we had GCH, which despite only being used as deep winter supplementary/backup heat source, needed to be described & included as the main source .... however, one of the recommended savings in the report was to install biomass heating which would save us £x / year ... unbelieveable!!

 ... then there's our approx 200sqm of ~500mm loft insulation which allowed the ticking of the highest box available, 300mm, thus overestimating the heat-loss by a considerable amount

... then there's no (tick box!!) ability to allow for what is essentially a 'trombe wall' porch for solar gain because it's not classified as being within the 'enclosed & heated' perimeter of the living space ... no tick box, no inclusion, no ability to include a considerable winter (low sun) heat source ...

Plenty of other issues too, but congratulations, the computer (using the RdSAP model) assesses your efficiency to be in the B band and your estimated energy use is X compared to the national average of Y .... odd really, because a proper analysis using a professional SAP materials based approach without assumptions done a few years earlier appraised the property as being borderline passivhaus with a full passivhaus modelled assessment showing it meeting all but one of the then energy efficiency requirements .... yet we're supposed to believe the EPC 'noddy ticks boxes' assessment???!!!

Anyway, for anyone still interested, there's a Passivhaus Trust report from 2020 (well after our experience) which is pretty decent & tends to fully support my thoughts ....  https://www.passivhaustrust.org.uk/UserFiles/File/research%20papers/EPCs/2020.04.17-EPCs%20as%20efficiency%20targets-v9.pdf .... well worth a few minutes reading to see what the real experts in the energy efficiency field really think of RdSAP and the EPC, especially the comparison between equally sized property energy requirements of an EPC A(93) rated property with PV (SAP 1665kWh/year) and an EPC C(80) rated passivhaus without PV (SAP 644kWh/year) ... laugh ??? - it's enough to make you cry at the fact you actually pay real money for an EPC assessment !!

HTH - Z

   

zeupater

Hi

Further to the above, and just to illustrate the absurdity of the assessment ... I've just pulled up the Green Deal Advice Report to check the savings referred to above as "one of the recommended savings in the report was to install biomass heating which would save us £x / year" and it's even more unbelievable than described ... the estimated annual savings for installing the recommended 'Wood Logs Boiler' was actually ... wait for it ... -£129 ... yes that was actually a recommended negative saving each year for investing in what we effectively already had in place!!!

To be fair though, throwing what we had in place in the scrap bin and spending thousands on a replacement would give us access to the (then) RHI scheme paying an estimated (their figures) of £2037 in year one !!! ... 'would you like me to arrange a couple of supplier to call to arrange a visit sir?' is something I seem to remember ... <cough> ...

I like our current stove & particularly dislike forms of systemic corruption but it makes one wonder how much taxpayer funding has been inappropriately awarded as a by-product of EPC assessments!!

HTH - Z     

paul991

they should make make it a obvious set  of  rules with a fixed number of points for each item of insulation or renewable generation so everyone could quite easily self assess .
only requiring a assessor  when a grant is applied for or a house sale.
I can see no point in having a reassessment carried out even though I have carried out  several improvements including PV since the last one. 
  

ABrass

If I remember right technically they have to assume that things like Cavity wall insulation isn't present (based on the age of the property), even if the owner says it's there unless there is clear evidence.

Photographs are accepted if they show every bit of it, for underfloor insulation that means every room need a photo. Screwdriver has those and receipts, either of which is normally good enough evidence, but EPCs aren't designed to take account of DIY work.

Screwdriva

ABrass said:

By underfloor insulation, was that the XPS stuff you used for the UFH? If memory serves it was 25mm XPS boards with the usual channel for the 16mm pipe to pop into.

Was there more than that underneath? Because I'm surprised that was considered good enough for the EPC.

The total measured insulation was 50mm (including the UFH boards) which is sufficient for the EPC's floor insulation requirement.

zeupater said:

Anyway, for anyone still interested, there's a Passivhaus Trust report from 2020 (well after our experience) which is pretty decent & tends to fully support my thoughts ....  https://www.passivhaustrust.org.uk/UserFiles/File/research%20papers/EPCs/2020.04.17-EPCs%20as%20efficiency%20targets-v9.pdf .... well worth a few minutes reading to see what the real experts in the energy efficiency field really think of RdSAP and the EPC, especially the comparison between equally sized property energy requirements of an EPC A(93) rated property with PV (SAP 1665kWh/year) and an EPC C(80) rated passivhaus without PV (SAP 644kWh/year) ...

I think this paragraph summarizes the report's primary gripe with the EPC's rdSAP methodology. 

"You might say that’s acceptable as the electrical energy generated by the PV offsets the energy used by the dwelling. However, the problem is that the emission rate associated with electricity is reducing due to more renewables at national level and is already lower than gas. As this reduces further, the emissions associated with a dwelling which uses gas (e.g. for heating and hot water) will far outweigh the emissions saving from generating electricity. This will be reflected in the environmental impact rating shown on the EPC, but, as mentioned earlier, this is rarely used and is not placed prominently on the EPC."

Clearly, the Passivhaus trust does not like gas being used for heating. But the report fails to account for the rather straightforward substitution of gas boiler with a heat pump (entirely compatible with an A rated home's insulation levels). Were this to be enabled in the EPC methodology going forward, as I expect it will be very soon, I wonder if the contrast with a purely electrically (emitters + immersion) heated Passivehaus would be as stark?

I'm willing to bet it won't be. Furthermore, the report's Figure 1 highlights a B rated home's marginal reduction in energy consumption but conveniently neglects to showcase the additional reductions from an A rated home. There are plenty of B rated homes but no A rated homes I can find in a multiple mile radius. 

ABrass said:

If I remember right technically they have to assume that things like Cavity wall insulation isn't present (based on the age of the property), even if the owner says it's there unless there is clear evidence.

Photographs are accepted if they show every bit of it, for underfloor insulation that means every room need a photo. Screwdriver has those and receipts, either of which is normally good enough evidence, but EPCs aren't designed to take account of DIY work.

Correct. No photo/ video evidence = no credit. Receipts don't count unless they clearly demonstrate the work was professionally installed (not just purchased).