Hertfordshire · Air handling unit cleaning
AHU Cleaning in Welwyn Garden City
For air handling unit cleaning in Welwyn Garden City, one call is all it takes, from survey to sign-off. CHAS and SafeContractor accredited, ISO 9001 and fully insured.
- Blocked condensate drains and slimy trays
- Dirty fans and fan housings
- Filters that are clogged or overdue
AHU cleaning in Welwyn Garden City, done properly
An air handling unit is the heart of a building’s ventilation: it draws air in, filters it, heats or cools it and pushes it round the ductwork. Whatever builds up inside it travels with that air, so cleaning the unit matters as much as cleaning the ducts. If you are dealing with odours coming through the supply air and dirty coils holding back the airflow, we can help, from dampers and louvres, supply and extract fans and filter sections onwards.
Buildings in towns like Welwyn Garden City often have ventilation added in stages, with units on the roof or in a plant room. The work starts with an inspection to decide what needs cleaning, so you are not paying for more than the system needs.
Every visit ends with a written report and pictures, so you have a record of what was done and when. Where the work is a TR19® Grease clean, the certificate is issued through the BESCA Vent Hygiene Elite portal.
- Where
- Welwyn Garden City (AL7, AL8, AL6)
- Region
- Hertfordshire
- Reporting
- Written report with pictures
- Quote
- A fixed price before any work starts
- Hours
- Out of hours as standard, 24/7 emergency line
- Telephone
- 0345 646 2711
- Updated
- 30 October 2026
What staff can safely do
Some jobs should never be done in-house: entering ducts, working on fans, testing dampers and taking grease readings call for the right kit, training and safe access. That is our job.
Away from the kitchen, the in-house job is mainly checking: clear grilles, a log of filter changes and reporting anything odd. The inside of ducts and units needs a specialist.
Why deal with it now?
A clogged coil or dirty fan makes the unit work harder for the same airflow. That means more wear on the motor and rooms that feel less fresh, and a planned clean is far less disruptive than a breakdown. Nothing in a duct, damper or fan improves by being left.
No two sites are the same, so we price each one individually. The size of the job, how we reach it, its condition and the working hours all make a difference.
Why us?
- Full insurance on every job
- One contact for all your sites in London and the South East
- Evenings, overnight and weekends, plus 24/7 emergency callout
- In business since 2009
See what affects the cost or our accreditations and certificates.
Welwyn Garden City questions
Can you clean school ventilation in Welwyn Garden City during the holidays?
Yes, and it’s the easiest time to do it. Around Welwyn Garden City, the Food Standards Agency lists about 21 schools and colleges with registered kitchens within a mile and a half or so. Send us your term dates when you give us a ring on 0345 646 2711, or send details by email, and we will fit the work in.
Do you offer AHU cleaning in Welwyn Garden City?
Yes, Welwyn Garden City is covered. You can ring 0345 646 2711 or drop us a line and let us know what needs doing.
What do you need from me for a quote?
Some photos and a quick description of the system plus the address and your hours. We’ll ask for anything else we need.
Are you insured?
Yes. Duct Doctor is fully insured, and we can share the details when you need them.
Where does the waste go?
It leaves the site with us when we go. While we work, it’s kept contained to keep the area clean.
What about areas you can’t get to?
They’re listed in the report, never skipped quietly. The report says which parts couldn’t be reached and why, and we can quote to improve the access.
Do you have a 24/7 line?
Yes. Our emergency line runs 24/7, for problems that cannot wait. Ring any time and tell us what’s happened.
Can you quote from photos?
Usually, 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 photos are not enough, we’ll survey first.
How the visit works
Before we leave, we walk the area with whoever is on site. Anything we couldn’t reach or that needs attention is pointed out there and then, and the same goes into the written report. All told, the work takes half a day to a full day per unit, with large plant planned over several shifts. The more we can see of the system beforehand, the smoother the visit to Welwyn Garden City will be.
- We look at the unit and the plant area during the survey.
- 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.
Preparing for the visit
- Clear the space around the work
- Let us know about parking and loading
- Allow time for equipment near the work to be turned off and cool down
How to get a quote
There’s no standard price list, because no two systems are the same. Instead, we look at your site first, from photos or a survey, and then give you a fixed quote. To start, give us a ring on 0345 646 2711, or send details by email.
Read more
Part by part
Drain trays
Condensate from the coil drips into a tray beneath it. We clear standing water, clean out slime and check the outlet is draining.
Rooftop and plant room units
Rooftop units take the weather, and intakes can collect leaves and debris. The intake section gets particular attention.
What affects the cost of AHU cleaning
A fixed price needs a few facts first. We check:
- The number of sites or systems
- Travel, parking and unloading
- One-off work versus a regular cycle
- How big the system is
You will not find a price list here, because the cost depends on the site in front of us. For a fixed quote, ring 0345 646 2711 or send us an email, and we will explain what it covers.
Asking for a quote
Photos and a few facts are often enough to price the work. Send what you can of the following:
- The postcode and the type of business
- Your last certificate, test record or report
- Close-ups of filters, grilles, hatches or access panels
- When the site is open and when it’s quiet
Quotes are quick. Send a few details and pictures, and we normally reply with a fixed quote within one working day. Where a survey is needed, we arrange a time that suits the site.
Aftercare tips
Results last longer with the right care. Here’s what we suggest:
- Make sure the unit’s access doors open easily
- Note any water around the unit or leaks below it
- Check the drain tray is emptying during routine visits
- Plan the next inspection before the last report gets filed away
The report suggests a date for the next inspection or clean, taking into account how dirty it was. Under TR19® Air the timing is set by inspection and risk, not a fixed calendar.
Have the unit inspected regularly, in line with the risk-based approach of TR19® Air, rather than waiting for a problem.
Landlords, agents and facilities managers
Where a tenant occupies the premises but the landlord owns the building, it’s worth checking the lease for who maintains the systems. We can quote either party and send the paperwork to whoever needs it.
We regularly work with managing agents. Send the address, what’s needed and how access works and we’ll come back with a fixed quote.
Welwyn Garden City buildings and their air
There are about 21 schools, colleges and universities, about 7 caring premises (care homes, nurseries and hospitals) and about 4 hotels, B&Bs and guest houses on the FSA’s food hygiene register within roughly a mile and a half of the centre of Welwyn Garden City. Busy, occupied buildings like these are where clean supply air matters most. Welwyn Garden City, about 21 miles from central London, is within our usual area. Evening, overnight and weekend visits are all possible. About 1.1 miles south of Welwyn Garden City is Queen Elizabeth II Hospital, the nearest hospital. If you run a surgery, clinic or care home, your ventilation deserves the same care as a hospital’s, on a smaller scale.
Queen Elizabeth II Hospital, about 1.1 miles south, is the nearest hospital to Welwyn Garden City, and healthcare sites of every size need their supply air kept clean. Wherever a school like Peartree Primary School has ducted ventilation, a half-term visit keeps the work out of lesson time. If you manage shops or offices close to Welwyn Garden City station, a TR19® Air inspection shows whether the ductwork needs cleaning.
Welwyn Garden City is in Hertfordshire. Across the AL7 area, we cover AHU cleaning for commercial sites. Welwyn Garden City is one of 381 towns, villages and districts in Hertfordshire we cover for commercial clients. For sites nearby, see our London page, about 21 miles away.
Every address in AL7, AL8 and AL6 is covered for AHU cleaning, from the main roads to the quietest streets. If you need AHU cleaning at premises on Church Road, Station Road and Lynmouth Road or anywhere close by, our technicians can take on the work. Welwyn Garden City is on the B195 and A1000, so it’s easy for us to get to for out-of-hours visits. If your site is just outside Welwyn Garden City, we cover Hatfield Hyde (1 mile south), Letty Green (3 miles south-east), West End (3 miles south), Essendon (3 miles south-east) and Staines Green (3 miles east). We also work in nearby towns such as Watford (13 miles south-west), Hemel Hempstead (12 miles west), Stevenage (8 miles north), St Albans (7 miles south-west), Harpenden (7 miles west) and Hitchin (11 miles north). As one of the bigger places in Hertfordshire, Welwyn Garden City has commercial sites of every size, all within our area for AHU cleaning.
Near you in Welwyn Garden City
Around Welwyn Garden City, our work takes us to kitchens and buildings near Stanborough Park, Sir Frederic Osborn School and The Bakehouse pub. The nearest railway station is Welwyn Garden City station, about 0.5 miles west of the centre. Nearby you will also find The Bunker at Hatfield Police Station (2.9 miles south-west) and Queen Elizabeth II Hospital (1.1 miles south). Not far away are Lemsford Springs.