EPC (energy performance certificate) and defective CWI

-
When selling a house, one of the 'services'  estate agents offer is to provide a EPC(Energy performance certificate) for the seller.
If you are selling your house then you must provide a certificate but it's actually quite cheap in the scheme of things (maybe £50-150) and you don't need an estate agent who may add a mark up to it.

The performance is based on algorithm which sums up negative and positive attributes of the house to derive an overall energy rating - it's not based on actual performance.
The Domestic Energy Assessor completing the EPC rating makes assumptions and doesn't check for presence of insulation. They will write things like (flat roof assumed no insulation).

In older houses, retrofit insulation does a lot to push up the rating:



However, what happens when you have damp insulation? Technically It's a negative rating as heating the inside of the house causes large thermal loss via heat transfer through the damp wall into the soggy insulation.
So when we bought our home it's likely that the rating was completely incorrect because it assumes that the CWI is working to specification.

The bizarre thing is, when the CWI is removed, the actual energy performance will be far better in the real world but when it comes time to sell the house the lack of CWI on the check list will result in a new certificate that is markedly worse on paper and this may even affect the sale price.

So really the EPC could be very misleading and by providing an attractive easy to understand summary, it may give potential buyers false reassurance as to the actual performance of a house.
Worse if we issue a new certificate after removing the CWI, the certificate will instruct the buyer that  the best course of action for improving efficiency is to install CWI.

 Update
It was pointed out to me that anyone can become a domestic energy assessor in 5 days by completing this course.
https://www.energy-trust.co.uk/products/domestic-energy-assessor-dea-5-day-course

Comments

Post a Comment

Popular posts from this blog

The controversy over Cavity Wall Insulation 'topups'

-
Image
In this article I talk about the practice and problems of topping up insulation when voids are discovered, why it is being done and the potential violations of building regulations. I can only put forwards what I have understood from public documents and personal correspondence  So I welcome corrections or clarifications from the industry on this important issue for home owners and will happily update this post to reflect any inaccurate statements. We know that 100s of topups are done every year.   From what I can gather : If the BBA have not approved these topups then the relevant local authority building control should have been notified prior to topping up as an 'off licence' use of the product.  It is not clear that the correct procedures are being followed in all cases. Background :Voids are common A void is simply an area cavity between the walls which is missing insulation.  If a void is large enough then the insulation will not be compliant with the meter square
Read more

CWI, Impermeable masonry paint, hard cement and breathability

-
Image
Waterproof or let's call it plastic masonry paint made with silicone or acrylic sounds like a fantastic idea to keep that pesky rain away from the wall. Unfortunately it can easily cause the opposite in terms of moisture management and inflict devastating damage to old solid walls which were originally made with a breathable building envelope. This article serves as a discussion to highlight some of the unexpected problems which show up in the real world verses the limited testing of the BBA certificates and I welcome discussion from anyone interested in this subject. For a good 'primer' on the problems associated with plastic paint in solid walls, Peter Ward from Heritage House has a number of videos of detailing the sacrilege caused by often well meaning tradesmen applying these aggressively marketed products. I recommend watching all his videos especially if you are having any sort of damp problems so that you can avoid the multimillion pound interventions sold by 
Read more

Discrepancies between Internal and external DPC (damp proof course)

-
Image
In a cavity wall construction, one would expect that the damp proof membrane to be at the same level on both walls. It turns out this is not always the case and my house is a good example where the internal wall's DPC is more than a brick lower than the external wall DPC. I didn't even think to check this before reading the CIGA Technical note 14 . This clearly states that if the distance between DPC and ground level is within a brick (as was the case with my property at time of install) then 'numerous other factors' must be assessed before declaring the dwelling as being suitable for CWI. CIGA  Technical note 14 . One of the factors is the relative level of the inner and outer leaf DPC. This is exactly what I found in my property. Ive used a floorboard to show the position of the internal floor. The DPC is clearly a brick below the floorboard and less than brick above the block paving. External leaf DPC is 1 brick below the floor level.
Read more