Delivering air tightness testing to replace inaccurate default EPC assumptions, unlocking better ratings without costly retrofit work.
Project Overview
- Client: Two Bristol-based commercial warehouse operators (names withheld for confidentiality)
- Sector: Commercial / Industrial
- Location: Avonmouth and Yate, Bristol
- Services Provided: Commercial EPC Assessment, Air Tightness Testing
- Scale: Two warehouse buildings – one 1970s, one recently retrofitted
- Target: MEES compliance (minimum E) and EPC rating improvement
The Challenge
Standard EPC assessments rely on default air permeability values when no actual test data exists – and for older or unusually constructed buildings, those defaults are often far more pessimistic than the building’s real performance. That’s exactly the trap both of these Bristol clients had fallen into: one had a 1970s Avonmouth warehouse rated F, an oil-heated building actively failing MEES compliance in the middle of a sale-and-leaseback deal; the other had a newly retrofitted Yate warehouse sitting at a high B, just a couple of points short of an A despite new cladding, roofing, and building services. Both needed a fast, cost-effective way to improve their rating – without the disruption or expense of further retrofit works.
The Solution
Air Testing for MEES Compliance (Avonmouth)
With the warehouse operating 24/7, we arranged a two-fan air test for a quiet Saturday morning slot to avoid disrupting operations. The building’s true air permeability came in at 7 – far tighter than the default value of 25 the original EPC assessment had assumed.
Air Testing to Close the Gap to EPC A (Yate)
Here the building was already performing well, but the assessment’s default air permeability figure was holding the rating back from the A band it was close to achieving. A single air test replaced that default assumption with a measured result of 15.
The Outcome
Both clients got exactly what they needed: fast, low-disruption certainty. The Avonmouth warehouse jumped from a failing F to a high D – clearing the MEES minimum with room to spare and letting the sale-and-leaseback proceed without further delay or the cost of replacing its heating system entirely. The Yate warehouse picked up the handful of points it needed to reach an A rating, turning an already-strong retrofit into a top-tier result. In both cases, an accurate air test proved far quicker and cheaper than any physical building intervention would have been – the problem wasn’t the building’s actual performance, it was an assessment that had never measured it properly.
