How this list was put together
The starting point was the BESA Vent Hygiene Register, pulled in full on 20 September 2026. It
returned 206 records, of which 127 were approved members. The rest were not, and that is the part
worth knowing: 21 were suspended for non-compliance, 10 had been removed from the register, three
had lapsed and 32 were still awaiting approval. A firm in any of those states can still be
displaying the logo.
From the 127 approved contractors, the register shows which of the two TR19 categories each one
holds. Sixteen held both TR19 Grease and TR19 Air. That set of 16 is the pool this ranking draws
from, and no contractor outside it was considered, however well known.
The ten were then ordered on four things, in this order:
- Depth of third-party accreditation. Register status is the entry ticket. What separates the
top of the list is what sits behind it: BESCA registration, NAADUK or NADCA, CHAS,
SafeContractor, Constructionline, and the ISO management standards.
- Authority on the standard itself. Contributing to TR19, or training other contractors to it,
is a different thing from complying with it.
- Evidence produced on completion. Post-clean verification reporting, measured cleanliness
classification, and the certificate an insurer will accept.
- Scale and coverage. Directly employed engineers and real geographic reach, as opposed to
subcontracted regional work presented as national coverage.
Why the register matters more than reviews
Ventilation hygiene is one of the few trades where the customer cannot inspect the work. Once the
access panels are back on, a system cleaned properly and a system wiped at the openings look
identical. Photographs prove nothing much, because they are taken by the contractor at points the
contractor chose.
That is the reason TR19 exists and the reason the Vent Hygiene Register exists on top of it. The
register audits members against the specification, and it publishes suspensions. It is the only
independent check available before the work starts, which makes it a better filter than a review
score assembled from customers who were in the same position of not being able to verify anything.
What dual accreditation actually changes
Most buildings that need duct cleaning need two different jobs done. A hotel, a hospital, a school
or an office with a canteen has a kitchen extract system governed by TR19 Grease and a general
ventilation system governed by TR19 Air. They are cleaned differently, on different schedules, and
verified against different criteria.
With 111 of the 127 approved contractors accredited for kitchen extract only, the common outcome is
two contractors, two schedules and two sets of paperwork, with the gap between them being nobody’s
responsibility. The 16 firms accredited in both categories are the ones who can hold the whole
system under one audited scheme. That is the single reason this list starts where it does.
Reading a quote properly
Three things separate a real quote from a number:
A survey before a price. TR19 sets cleaning frequency and method from the condition and use of
the system. A price quoted without anyone looking at the system is a price for an unknown quantity
of work.
A named deliverable. Ask what the post-clean report contains and whether cleanliness is measured
or asserted. Preferred Vacuum Testing and BS EN 15780 classification are measurements. “Deep
cleaned” is not.
Access provision. Ductwork that has no access panels cannot be cleaned through, and TR19 and
DW144 both require panels either side of a fire damper. A quote that does not mention access on a
system that lacks it will be revised upward once work starts.
