Air handling units (AHU) in Hertfordshire

An air handling unit (AHU) is the central plant that filters, moves and often heats, cools or recovers heat from the air for a building's ventilation system. We replace ageing units, upgrade fans and controls, and service AHUs so they keep delivering their design airflows.

Every job in Hertfordshire gets a written quote before it starts and a commissioning record when it finishes. We cover Watford, Hemel Hempstead, Stevenage, St Albans and Welwyn Garden City and the villages around them.

Air handling units in Hertfordshire at a glance

Area: Hertfordshire
Towns listed: 32, largest Watford
Postcode districts: HA6, WD3, EN6, WD2, HP1 and HP4
Price region: East of England
Survey: Free survey (UK mainland)

How we do it

Replacing the fan section with EC fans, or the whole unit with a modern heat recovery AHU, can cut running costs and noise while restoring airflow. New units must meet current ecodesign rules for fan efficiency and heat recovery. Replacements often involve crane lifts, roof work and out-of-hours changeovers.

Like-for-like replacement

New unit in the same position, connected to existing ductwork.

EC fan retrofit

Belt-driven fans replaced with direct-drive EC fans.

Controls upgrade

New controls, sensors and BMS integration.

Guide prices in Hertfordshire

Air handling units (AHU) guide prices in Hertfordshire
Work	Guide price
Air handling unit replacement, small to medium unit, like-for-like position (per unit)	£10,450–£36,700 + VAT
Air handling unit service: filters, belts or EC fan check, coils, controls (per unit per visit)	£205–£415 + VAT

East of England rates shown. Prices exclude VAT. The fixed price is confirmed in writing after we have seen the job.

When to get it looked at

Rising energy bills from old plant
Frequent belt or fan failures
Noisy plant rooms or rooftop units

Rules in England

In England, ventilation is covered by Part F of the Building Regulations and its guidance, Approved Document F (2021 edition). Workplaces must also be ventilated with a sufficient quantity of fresh or purified air under the Workplace (Health, Safety and Welfare) Regulations 1992.

How the job runs

Survey
Options
Plan
Install
Commission

Towns we cover in Hertfordshire

Questions about air handling units (AHU) in Hertfordshire

Is the survey free in Hertfordshire?

For new installations on the UK mainland, yes. The survey is free and the quote that follows is fixed and in writing. Servicing, testing and repair visits are charged, and we confirm the cost before booking.

Is it worth replacing belt-driven fans with EC fans?

Often yes. EC fans are usually more efficient, quieter and need no belt changes, and the retrofit can cost much less than a new unit.

Can you work out of hours?

Yes. Changeovers and crane lifts are often done at weekends or evenings to avoid disruption.

Which rules apply to ventilation in Hertfordshire?

In England, ventilation in new and altered homes is covered by Approved Document F of the Building Regulations. Landlords also have duties under the Housing Health and Safety Rating System, and workplaces must be ventilated under the Workplace (Health, Safety and Welfare) Regulations 1992.

Which towns in Hertfordshire do you cover?

All of Hertfordshire, including Watford, Hemel Hempstead, Stevenage, St Albans and Welwyn Garden City. If your town is not listed, send the postcode and we will confirm.