Hi all, I'm finally getting our EPC done and have been told that as it stands we wont need an air permeability test, this is what the chap has written to me:

 

"As it stands, without an air test, the property has an EPC of 99A and a DER of 1.20kgCO₂/yr/m². With an air test target of 10 the property would have an EPC of 104A and a DER of -2.15kgCO2/yr/m2, with a target of 5.0 (which is around the target the MVHR system would need in order to perform efficiently) the EPC would be 108A and a DER of -5.21kgCO2/yr/m2."

 

I'd quite like to do without and avoid the cost, but I'd also quite like to know exactly what we've managed to achieve. Are there any other implications of not getting the test done though? 

Air test is small fry in the total cost of the build, depends on what you declared on the drawings, anything better than a 10 would demand an airtest I assume (living in Scotland - it was a sign off document for the completion certificate).

 

So look at the requirements for BR sign off

33 minutes ago, Tom said:

I'd also quite like to know exactly what we've managed to achieve

Maybe buildhub needs a league table of air test scores? After going to the trouble of trying to be airtight I'll definitely have to know how we've done!

 

I'm not sure exactly how much value a future buyer might place on EPC but being able to boast a 100+ score and being carbon negative must be worth the cost of a test. (Alternatively, if it's really bad you'll know it's not worth running the MVHR all the time)

Under the current Regs (after June 2022) ALL new dwellings must have an air pressure test done and this value is used to assess BR compliance and in the EPC.

 

Under the previous version of the Regs it was possible to avoid the test for developments of no more than 2 dwellings by using a default air permeability value of 15 m3/(h.m2) at 50 Pa and this value is used to assess BR compliance and in the EPC. More often than not this will result in a BR failure. If an air pressure test is done the measured value is used to assess BR compliance and in the EPC.

 

Both are Building Control issues and your SAP assessor should be aware.

Same score as us. I would have thought curiosity, if nothing else, would encourage you to get the air tightness test result. Bit late to do anything about it now of course if it’s crap other than switch off the MVHR. Like @JohnMosays it’s been a requirement in Scotland for final sign off for some time. 
 

You are right about you being the only person interested in it. The next buyer likely won’t be unless the cost of electricity gets high enough that low running cost houses attract a premium. Even my other half wasn’t that interested other than what was required to get the final sign off. 

2 hours ago, ADLIan said:

Under the current Regs (after June 2022) ALL new dwellings must have an air pressure test done

 

I'm being pedantic here. Often there is a difference between "The Requirement" and the multiple explanatories following it, or summaries by other parties.

 

Not all bcos even realise this or appreciate any question of it.

 

Must or should or may?

 

"Must be reasonably airtight" as opposed to ' here are the standards expected.

 

In reality it is usually easier and as cheap to test than to argue the case another way.

 

I haven't done hours of checking this and am not going to... we will get an air test.

But if anyone knows I'm wrong, and it is a requirement in the green bit of the regs,  I'd be interested. 

 

The Regulation, direct guidance and SAP guidance are all clear and consistent on current air pressure testing requirements.