Hertfordshire · Air handling unit cleaning
Air handling unit cleaning in Farnham, Hertfordshire
One call covers air handling unit cleaning in Farnham, from survey to sign-off. CHAS and SafeContractor accredited, ISO 9001 and fully insured.
- Dust-coated heating and cooling coils
- Odours coming through the supply air
- Intake sections clogged with outdoor debris
Farnham: your questions answered
Can you work in Farnham outside opening hours?
Yes, nights and weekends are routine for us. It means the site in Farnham keeps running as normal. When you call us on 0345 646 2711, or email photos, mention when the site is quiet.
Is Farnham within the area you cover?
Yes, we work in villages as well as towns, and Farnham is covered. Just mention lanes, gates or anything else about the site when you book.
What is TR19?
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, and TR19® Air covers general supply and extract systems.
Can you come out in an emergency?
Yes, any time. For anything urgent, such as a fan failure or damage after a fire, ring the 24/7 line and we’ll talk you through the next steps.
What should I send you?
Just the basics: where it is, what kind of site, when it’s open and the access. Photos and any previous paperwork make it quicker. After that, simply ring 0345 646 2711 or use the quote form.
Will we get paperwork for the AHU clean?
Yes, both a certificate and a report with pictures. It includes a recommended date for the next check.
What if parts of the system cannot be reached?
The report shows them clearly. Often the fix is extra access, such as new panels in ductwork, which we can install.
Is a quote from pictures possible?
In many cases, yes. With good photos, the site type and your last report, we can price many jobs. Where we cannot see enough, we arrange a survey.
AHU cleaning in Farnham
Units vary a lot in size, age and layout, from a small ceiling-mounted unit to a large rooftop plant. We look at the unit first, from pictures or a site visit, and give you a fixed quote before any cleaning starts. The work covers dampers and louvres, internal panels and drain trays, and people most often call us about air handling units with blocked filters and rooms that smell stuffy when the system runs.
Work in a small place like Farnham starts with agreeing access and timings.
For insurers and inspectors, the record counts. That is why every job is written up in a report with pictures, and grease extract cleans come with a TR19® certificate issued through the BESCA Vent Hygiene Elite portal.
- Location
- Farnham (CM23)
- Wider area
- Hertfordshire
- Reporting
- Report and photos after the visit
- Quote
- A fixed price before work begins
- Hours
- Out of hours as standard, 24/7 emergency line
- Call
- 0345 646 2711
- Updated
- 30 October 2026
Aftercare tips
Once we’ve finished, these simple steps help:
- Change filters on schedule and log each change
- Look at the condensate drain whenever the unit is serviced
- Diary the inspection date recommended in the report
- Report stiff or damaged access doors
Stick to the filter change schedule, as that does more than anything to keep the unit clean. Record each change in the maintenance log.
Keep the area around the intake clear. Anything around the intake is likely to be drawn in.
Managing agents and facilities teams in Farnham
Running several sites is easier with one contractor. We work across London and the South East, so a run of sites can go into one programme and kept on a regular cycle.
We also work for facilities teams across offices, schools and healthcare across Hertfordshire. Work can be phased by floor, building or site to keep disruption down.
What affects the cost of AHU cleaning
Every site gets its own quote. These are the things that affect it:
- How big the system is
- Access, including roofs, risers and ceiling voids
- Working hours and out-of-hours timing
- Travel, parking and unloading
Whatever the type of site, the quote works the same way: the size of the job, access, condition and working hours. Call for a fixed quote and we will explain each part.
What to send for a quote
Photos let us diagnose from a distance. The most useful are:
- Close-ups of filters, grilles, hatches or access panels
- Your opening hours and when the area is out of use
- Where the plant sits or the system leaves the building, such as a roof or outside wall
- The site address and the type of premises
Photos are the quickest way to a quote: the system from a couple of angles, plus any access panels or hatches. Tell us what kind of site it is and when it’s open, and we can price many jobs without a visit.
Different parts, different methods
Rooftop and plant room units
Many AHUs sit on roofs or in plant rooms with limited access. We plan safe access as part of the survey so the quote reflects it.
Fans and fan sections
Dust on a fan impeller adds weight and wear. Cleaning keeps it running as intended.
Ventilation in Farnham buildings
There are about 3 schools, colleges and universities on the FSA’s food hygiene register within 1.5 miles or so of the middle of Farnham. Buildings like these often rely on mechanical ventilation, which TR19® Air covers. At about 30 miles from central London, Farnham sits well inside the area we cover. The visit is fixed around your opening hours, not ours. Herts and Essex Hospital is the nearest hospital, about 2.8 miles south-east of Farnham. Hospitals show how much a building can rely on its ventilation, and smaller healthcare sites rely on theirs too.
Healthcare buildings such as Herts and Essex Hospital, about 2.8 miles south-east, depend on their ventilation; if you manage a surgery, clinic or care home near Farnham, yours matters too.
Farnham is about 2 miles north of Bishop's Stortford, in Hertfordshire. We carry out AHU cleaning for commercial premises of every kind in Farnham and the rest of Hertfordshire. Across Hertfordshire, we cover 381 places, Farnham among them. Chelmsford is in our area too, about 19 miles from Farnham.
AHU cleaning in CM23 is surveyed, quoted and booked the same way as anywhere else. Nearby, we also carry out AHU cleaning in Uppend (1 mile north), Mount Pleasant (1 mile north), Manuden (2 miles north-east), Bentfield Green (2 miles east) and Stansted Mountfitchet (2 miles east). Larger places within reach include Stevenage (14 miles west), Hoddesdon (12 miles south-west), Hertford (12 miles south-west), Ware (10 miles south-west), Baldock (15 miles north-west) and Broxbourne (13 miles south-west).
Landmarks near Farnham
Around Farnham, our work takes us to kitchens and buildings near St Mary's Catholic School and the streets around them. The nearest railway station is Stansted Mountfitchet station, about 2.4 miles east. Other landmarks nearby include Moated mound (1.7 miles south-west) and Herts and Essex Hospital (2.8 miles south-east). The countryside around Farnham includes Portingbury Hills and Aubrey Buxton Nature Reserve.
What we are called out for in Farnham
An overdue filter loads up with dirt, cutting airflow and sometimes letting dirty air bypass them altogether. Then the rest of the unit takes the load.
Keep an eye out for any of the following:
- Units that have only ever had filter changes
- Leaves and litter drawn into the unit
- Fan sections that haven’t been cleaned in years
- Units needing a clean before a new tenant or handover
If you manage a school such as Farnham Church of England Primary School, ventilation cleaning is best booked for the holidays.
Comparing quotes
- How they set the interval to the next visit
- When they can work, and whether that’s outside your opening hours
- Exactly which parts of the system are covered
- Proof of insurance
How it works
Every visit runs to the same pattern: sheeting and protection first, isolate whatever needs isolating, carry out the AHU cleaning, clear away and hand over the paperwork. On site, the work takes a single shift for a typical unit, longer for large or heavily soiled ones. Photos of the system and how to reach it help us plan a visit to Farnham.
- First we agree when the unit can be switched off, including evenings or weekends.
- We take before photos of each section of the unit.
- Filters, coils and internal surfaces are cleaned from intake to discharge.
- The fan and drain tray are cleaned and the drain checked.
- We take after photos and issue the certificate and report.
Getting ready for the visit
- Arrange a key holder or contact on site
- Let us know about permits to work or site inductions
- Let us know how we reach the system, including roofs, risers and plant rooms
Getting a quote
For a fixed quote, give us a ring on 0345 646 2711, or send details by email with the site type, your trading hours and a short description of the system. A few photos and your last certificate or report help a lot. You will typically have a quote within one working day.
Related advice
Towns and villages near Farnham
More services for Farnham
When it’s something else
It’s worth knowing the limits before booking:
- Leaking heating or cooling coils
- Dirty ducts beyond the unit itself
- Building management system faults
Not sure which it is? You can call us on 0345 646 2711 or use the quote form and we’ll tell you honestly before booking.
What the work covers
- Drain trays
- Dampers and louvres
- Filter sections
- Internal panels
- Supply and extract fans
- Heating and cooling coils