Hertfordshire · Air handling unit cleaning
Air handling unit cleaning in Old Knebworth, Hertfordshire
Air handling unit cleaning for commercial sites in Old Knebworth and across Hertfordshire. CHAS, SafeContractor and ISO 9001, and fully insured.
- Odours coming through the supply air
- Dust-coated heating and cooling coils
- Fan sections that haven’t been cleaned in years
What happens on the day
The first job on site is protection: floors, worktops and anything near the work are covered. Then we make the system safe and start. It takes anything from half a day for one small unit to several shifts for a plant room full of them, and we clear up before we go. Somewhere like Old Knebworth, lanes, gates and parking are worth mentioning in advance.
- The survey covers the unit, its access and how it can be shut down.
- The area is protected and the unit made safe.
- Dirt and debris are removed from each section.
- Coils and trays are cleaned and the condensate drain cleared.
- We close every panel, hand the unit back and send the report and certificate.
Getting ready for the visit
- Tell us the best time to work, such as after service or at a weekend
- Tell us about access, such as roof hatches, plant rooms, ceilings or locked areas
- Name a contact who can let us in at the agreed time
Ask for a quote
To help us quote: where the site is, what it is and its opening hours, pictures of the system and any previous report or certificate. Once you have those, phone us on 0345 646 2711, or send details by email.
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AHU cleaning for kitchens and businesses in Old Knebworth
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. We are often asked to deal with units needing a clean before a new tenant or handover and fan sections that haven’t been cleaned in years, across filter sections, heating and cooling coils and supply and extract fans.
Somewhere as small as Old Knebworth, ducted ventilation is typically limited to a school, a care home, a surgery or a converted business building, wherever there is one, but where it’s fitted, it needs the same inspection and cleaning as anywhere.
Insurers, fire officers and environmental health officers all look at records. So every job comes with a written report and pictures, and grease extract cleans come with a TR19® certificate issued through the BESCA Vent Hygiene Elite portal.
- Location
- Old Knebworth (SG3)
- Wider area
- Hertfordshire
- Paperwork
- Written report with photos
- Quotes
- A fixed quote up front
- When we work
- After hours by arrangement; emergencies any time
- Phone
- 0345 646 2711
- Page updated
- 30 October 2026
What AHU cleaning can’t fix
An honest diagnosis matters more to us than a booking, so here’s what this work cannot put right:
- Problems with the unit’s controls or sensors
- The supply and extract ducts, quoted separately
- Faulty motors, drives or bearings
If in doubt, call 0345 646 2711, or send details by email and we will say what we think before booking.
What we work on in Old Knebworth
- Heating and cooling coils
- Internal panels
- Filter sections
- Drain trays
- Supply and extract fans
- Dampers and louvres
Nearby places to Old Knebworth
More services for Old Knebworth
Landlords, agents and facilities managers
We work for landlords, managing agents and facilities managers as well as the people running the site. Where a system serves more than one tenant, such as a shared riser, it helps to agree who arranges the work, and we can quote for the whole system.
If you look after several sites, we can plan visits across the whole estate and price them together. Each site gets its own report and pictures, so records stay tidy.
Common problems we fix in Old Knebworth
Cooling coils create condensation, and that water has to go somewhere. If the drain tray outlet blocks or the tray does not fall properly, water stands in it, and slime and smells soon follow.
Look out for these warning signs:
- Units needing a clean before a new tenant or handover
- Dirty fans and fan housings
- Drain trays holding standing water
- Coils clogged with dust and debris
Lister Hospital, about 3.7 miles north, is the nearest hospital to Old Knebworth, and healthcare sites of every size need their supply air kept clean.
What your quote should include
- How they set the interval to the next visit
- Whether they’re fully insured
- How VAT is shown on the quote
- What’s included in the scope, part by part
AHU cleaning around Old Knebworth
Food Standards Agency data includes about 7 care, childcare and hospital premises across Old Knebworth and its immediate surroundings (about a mile and a half). Classrooms, bedrooms and care spaces are often served by ducted air, and that ductwork collects dust over time. We cover Old Knebworth, about 26 miles from central London, as part of our work across London and the South East. Visits are booked around your hours, evenings and weekends included. Lister Hospital is the nearest hospital, about 3.7 miles north of Old Knebworth. If you run a surgery, clinic or care home, your ventilation deserves the same care as a hospital’s, on a smaller scale.
For schools like Barnwell School, the holidays are the usual time to inspect and clean ventilation.
Old Knebworth is about 3 miles south-west of Stevenage, in Hertfordshire. We carry out AHU cleaning for businesses, landlords and public buildings in Old Knebworth and the rest of Hertfordshire. Old Knebworth is one of 381 places in Hertfordshire we cover for AHU cleaning. London is in our area too, around 26 miles away.
Every address in SG3 is within our area for AHU cleaning, from the main roads to the quietest streets. Whether your site is on Old Knebworth Lane and Park Lane or anywhere close by, our technicians can take on the work. We also cover the places around Old Knebworth: Nup End Green (1 mile south-west), Driver's End (1 mile south-west), Rableyheath (1 mile south), Pottersheath (1 mile south) and Langley (2 miles north-west). We also work in nearby towns such as Hemel Hempstead (13 miles south-west), Stevenage (3 miles north-east), St Albans (10 miles south-west), Welwyn Garden City (5 miles south), Harpenden (7 miles south-west) and Hitchin (6 miles north-west).
Near you in Old Knebworth
Locally, jobs take us to businesses close to Knebworth Park and Robin Hood And Little John Public House, among other places. Old Knebworth’s nearest station is Knebworth station, roughly 1 mile east. Nearby you’ll also find Lister Hospital (3.7 miles north) and Stevenage Museum (2.2 miles north). The countryside around Old Knebworth includes Mardley Heath.
Why deal with it now?
Cleaning a unit while it only has light dust is quick. Years of build-up make the job longer and harder, especially where there’s been moisture. Our emergency line runs 24/7, but a planned visit to Old Knebworth is calmer for everyone.
Whatever the type of site, the quote works the same way: how much there is, how we reach it, what state it’s in and when we can work. Ask for a fixed quote and we’ll explain each part.
Why choose Duct Doctor in Old Knebworth
- One contact for all your sites in London and the South East
- A BESCA Vent Hygiene Elite member, cleaning to BESA TR19® Grease
- Ventilation hygiene specialists since 2009
- A fixed price before any work starts
Read our cost guide or our accreditations.
What affects the quote in Old Knebworth
Before we fix a price, we need to know a few things. We check:
- What state the system is in
- Whether it’s a one-off visit or part of a schedule
- The scale of the work
- Site requirements such as sign-in and permits
You will not find a price list here, because each job is priced on what it involves. Call for a fixed quote, and we will explain what it covers.
Asking for a quote
There’s no need for technical detail. Just send:
- The paperwork from the last visit, if you have it
- Any symptoms, from odd noises to smells or leaks
- The postcode and the type of business
- A few general shots of the system
Getting a quote doesn’t take long. Call or email with a few details and you will typically have a fixed price within one working day. Where a survey is needed, we arrange a time that suits the site.
Between visits
Here’s the after-treatment advice, in brief:
- Report stiff or damaged access doors
- Note any water around the unit or leaks below it
- Keep the certificate and photo report with the plant records
- Clear leaves and litter away from the intake
Once the clean is done, we send a TR19® certificate and a report with before and after photos. They belong in the plant or maintenance log.
Keep the unit’s doors and panels in working order. If a section is hard to get into, it tends not to get checked.
Common questions in Old Knebworth
Do you work at weekends in Old Knebworth?
Yes, out-of-hours work is a big part of what we do. That way a site in Old Knebworth doesn’t have to lose a day’s trading. Just ring 0345 646 2711, or email photos with your opening times and we’ll plan around them.
Will you come out to Old Knebworth?
Yes, smaller places are covered as well as towns. Let us know about access, parking and anything unusual about getting there when you book.
What should I send you?
Where the site is, what it is and when it’s open, plus pictures of the system and your last certificate or report if you have one.
Can you set up regular visits?
Yes. Plans on a 3, 6 or 12-monthly cycle are available, to suit the system and how it’s used.
What do you clean inside the unit?
Filters, coils, drain trays, the fan and the internal surfaces are all covered. What happens to the filters is agreed when we quote.
Do you work with multi-site operators?
Yes. You deal with one contact for every site in our area, and visits can be set on a regular cycle.
When should our AHU next be cleaned?
TR19® Air takes a risk-based approach, so it depends on inspection rather than a fixed interval. Each report suggests when the unit should next be looked at.
How much does AHU cleaning cost in Old Knebworth?
Size, condition, access and working hours all affect the cost. Call for a fixed quote, normally ready within one working day.