Hertfordshire · Air handling unit cleaning
Digswell AHU cleaning
AHU cleaning in Digswell, surveyed first and signed off with a written report and pictures. Ask us for a fixed quote.
- Stale or musty smells from the ventilation
- Air handling units never cleaned inside
- Dirty filters cutting the airflow
Why deal with it now?
Facilities teams are often asked for evidence that the ventilation is looked after. A TR19® certificate and photo report give you that, for audits, tenants or your own peace of mind. A visit arranged in advance is far less disruptive than a callout on a busy day.
We don’t list prices on the website, because each job is priced on what it involves. Call for a fixed quote, and we’ll talk you through it.
Why choose Duct Doctor in Digswell
- In business since 2009
- Every job surveyed first
- CHAS and SafeContractor accredited, with ISO 9001
- A BESCA Vent Hygiene Elite member, cleaning to BESA TR19® Grease
Take a look at what affects the cost or our accreditations and certificates.
AHU cleaning in Digswell
The fan pushes every bit of air in the system, so dust on its blades and housing ends up in the airstream. We clean the fan section along with the rest of the unit, once the unit has been shut down and isolated. The work covers supply and extract fans, heating and cooling coils and internal panels, and common reasons people get in touch are air handling units due a clean after building work and fan sections that haven’t been cleaned in years.
For a building near Digswell, the visit is planned around how it’s used, and the journey is planned ahead. The method doesn’t change: inspect first, clean, then record what was done.
A written report with photos follows each visit, so there’s a dated record of the work. Kitchen extract cleaning to TR19® Grease is certificated through the BESCA Vent Hygiene Elite portal.
- Location
- Digswell (AL8, AL7, AL6)
- Region
- Hertfordshire
- Paperwork
- Photo report after each visit
- Quotes
- A fixed quote up front
- When we work
- Nights, weekends or holidays to suit you
- Telephone
- 0345 646 2711
- Page updated
- 30 October 2026
Digswell buildings and their air
The FSA’s food hygiene register lists about 15 schools, colleges and universities and about 5 care, childcare and hospital premises with registered kitchens or food service across Digswell and its immediate surroundings (about a mile and a half). Busy, occupied buildings like these are where clean supply air matters most. About 2.5 miles south of Digswell is Queen Elizabeth II Hospital, the nearest hospital. Hospitals show how much a building can rely on its ventilation, and smaller healthcare sites rely on theirs too. Digswell, about 23 miles from central London, is within our usual area. Visits are booked around your hours, evenings and weekends included.
If you manage a school such as Harwood Hill Junior Mixed Infant and Nursery School, ventilation cleaning is best booked for the holidays. If you manage offices or shops near Welwyn North station, their ventilation can be inspected and cleaned out of hours.
Digswell is about 1 mile north of Welwyn Garden City, in Hertfordshire. For AHU cleaning in and around Digswell, it’s easy to get a fixed quote: please call us on 0345 646 2711 or drop us a line. Our area covers London and the South East, including Digswell. Across Hertfordshire, we cover 381 places, and Digswell is one of them. There’s also a page for London, roughly 23 miles from Digswell.
All of AL8, AL7 and AL6 is covered for AHU cleaning, from busy streets to back roads. If you need AHU cleaning at premises on Adele Avenue, Station Road and Hertford Road or anywhere close by, our technicians can take on the work. We also cover Haldens (1 mile south-east), Harmer Green (1 mile north-east), Burnham Green (2 miles north-east), Oaklands (2 miles north) and Tewin (2 miles east). Larger places within reach include Watford (14 miles south-west), Hemel Hempstead (12 miles west), Stevenage (6 miles north), St Albans (7 miles south-west), Harpenden (6 miles west) and Hitchin (10 miles north).
Local landmarks in Digswell
We work in commercial kitchens and buildings around Hedgehog pub, Monk's Walk School and Danesbury Park, among other places. There’s a railway station in Digswell itself: Welwyn North station. Well-known places in the area include Howard Centre (1.3 miles south) and Datchworth Museum (2.6 miles north-east). For a walk, there’s Tewin Orchard and Hopkyns Wood.
More services for Digswell
When to call us in Digswell
An AHU’s intake draws in outdoor air and everything in it: dust, pollen, leaves and debris. The intake section and first filters take the brunt, and some travels further into the unit.
Signs it’s time to call us include:
- Drain trays holding standing water
- Dirty filters cutting the airflow
- Intake sections clogged with outdoor debris
- Dirty fans and fan housings
Healthcare ventilation, from large hospitals like Queen Elizabeth II Hospital (about 2.5 miles south) to small clinics, depends on clean filters, coils and ducts.
Questions to ask before booking
- If they look at the system before pricing
- Their accreditations, such as BESCA Vent Hygiene Elite, CHAS or SafeContractor
- Whether the work can be done while the site is closed
- Proof of insurance
In-house cleaning or a specialist?
For ventilation and air handling systems, in-house care is mostly about checks: keeping grilles clear, noting unusual noise or smells and logging filter changes. The inside of ducts and units needs a specialist.
Logging matters as much as cleaning. A simple log of filter washes, wipe-downs and checks shows an inspector that the system is looked after between visits, alongside our reports.
For landlords and multi-site operators
We work for landlords, managing agents and facilities managers as well as the people running the site. Shared systems, like a riser serving several units, need a clear agreement on who books the work, and we can quote for the whole system.
From a single site to a large estate, you get the same standard: a survey first, a fixed quote, the work timed around the site and a report with photos.
What happens on the day
The first job on site is protection: sheeting goes over floors and surfaces close to the work. Then we make the system safe and start. The work on site takes a single shift for a typical unit, longer for large or heavily soiled ones, and we clear up before we go. Visits to a place like Digswell are planned ahead, so we arrive with what the survey says the job needs.
- The survey covers the unit, its access and how it can be shut down.
- We sheet the area and the unit is isolated.
- Each section is cleaned of dust, debris and slime.
- Coils and trays are cleaned and the condensate drain cleared.
- The unit is closed up and handed back, with a report to follow.
Getting ready for the visit
- Tell us about site rules, permits or sign-in
- Clear the space around the work
- Name a contact who can let us in at the agreed time
Get a fixed quote
For a fixed quote, call 0345 646 2711, or email photos with the site type, your trading hours and a short description of the system. Photos and the last report, if you have one, make the quote quicker. We usually come back within one working day.
Related advice
Honest limits
Not every problem is solved by AHU cleaning, and we’ll tell you before any work starts. It does not solve:
- The supply and extract ducts, quoted separately
- Ventilation that was badly designed in the first place
- Problems with the unit’s controls or sensors
If you’re not sure, just call us on 0345 646 2711, or send details by email and we’ll give you a straight answer before you book.
Parts of the system we cover
- Drain trays
- Filter sections
- Heating and cooling coils
- Supply and extract fans
- Dampers and louvres
- Internal panels
What the work involves, part by part
Fans and fan sections
Build-up on fan blades can upset the balance and add wear. A clean fan runs more smoothly.
Internal casing and panels
Damaged internal linings or loose panels can shed material into the air. Anything like that is recorded with photos.
Questions from Digswell
Do you work overnight in Digswell?
Yes, out-of-hours work is a big part of what we do. It means the site in Digswell keeps running as normal. Let us know the hours you are closed and we will book within them.
Will you come out to Digswell?
Yes, Digswell is part of our area, however small the site. Just mention lanes, gates or anything else about the site when you book.
Can you set up regular visits?
Yes. Regular plans can run on 3, 6 or 12-monthly cycles, depending on what the system needs.
What does TR19 mean?
TR19® is the BESA specification for keeping ventilation systems clean. Since 2019, TR19® Grease has been a standalone specification for grease in kitchen extract systems, while TR19® Air covers other supply and extract ductwork.
Can you quote from photos?
Normally, yes. Send wide shots, close-ups of any access panels and anything that worries you, and a fixed quote normally follows within one working day. If pictures are not enough, we’ll survey first.
How long does it take to clean an air handling unit?
The work takes a single shift for a typical unit, longer for large or heavily soiled ones. Large plant can be split over several shifts, and you can ring 0345 646 2711 or email us to plan it.
Can you fix a faulty AHU?
Our AHU work is cleaning rather than mechanical repair. If we spot a fault, we note it in the report for your maintenance team to follow up.
Do you give a certificate after the clean?
Yes, both a certificate and a report with photos. The report also suggests when the unit should next be inspected.