What does a commercial ventilation or MVHR system cost?

What sets the cost of a commercial ventilation system?

Five things, roughly in this order: the airflow the occupants need, the type of unit, its heat-recovery and fan specification, the ductwork and dampers around it, and the controls and commissioning. Prices for these come from quotes rather than an official source, so this page explains what moves a quote and prices only the running cost, using DESNZ's electricity figure.

Published equipment list prices for compact heat-recovery units, with their dates and VAT basis, are on the air handling unit cost guide. This page does not repeat them.

How much air does the building need?

Airflow comes first because it sizes every other component. Under regulation 6 of the Workplace (Health, Safety and Welfare) Regulations, employers must ensure that every enclosed workplace is ventilated by a sufficient quantity of fresh or purified air. HSE quotes its Approved Code of Practice: the fresh-air supply rate should not normally fall below 5 to 8 litres per second per occupant. It adds that some building guides recommend 10 litres per second per person as suitable for most commercial buildings.

Approved Document F Volume 2 is the current Building Regulations guidance in England for buildings other than dwellings, and the ventilation requirements guide explains how it relates to the workplace duty. As arithmetic, a room with 40 occupants needs 200 to 320 litres per second at 5 to 8 litres each, or 400 litres per second at 10 litres each. That is 720 to 1,152 cubic metres an hour, or 1,440.

Which type of unit, and what does the law require of it?

Unit type	What it is	What drives the price	Running-cost point
Central balanced unit	Supply and extract fans with heat recovery, connected to ducts	Plant space, two sets of ductwork, dampers, heat-recovery specification	Two air streams to move; recovered heat offsets the fan power
Decentralised unit	One unit per room or zone, not intended for duct connections	Number of units, wall penetrations, a power supply and controls at each	Many small fans and many filters to change
Extract-only unit	Exhaust fan, with air entering by natural or separate supply	Simplest equipment; the make-up air path still has to be designed	Lowest fan power; no heat recovery

The ecodesign regulation sets the floor for all three. A ventilation unit whose maximum flow exceeds 250 cubic metres an hour counts as non-residential, unless it is between 250 and 1,000 and declared exclusively for residential use, so the 1,440 in the example is well inside it. Since 1 January 2018, every unit except a dual-use unit needs a multi-speed or variable-speed drive, every bidirectional unit needs a heat recovery system with a thermal by-pass, and an extract-only unit used with a filter has an internal specific fan power limit of 230 watts per cubic metre a second. The decentralised MVHR guide covers the single-room option in detail.

The regulation also requires product information for non-residential units. It includes the thermal efficiency of heat recovery, the static efficiency of the fans, the energy performance of the filters, a description of the visual filter warning and, for indoor units, the casing sound power level. Asking for these figures in every quote makes two units comparable.

What do ductwork, dampers and commissioning add?

BESA's DW/144 covers low, medium and high pressure ductwork, including air leakage limits and performance classes and the integration of smoke and fire dampers. BESA says Class C is the most commonly used leakage class in commercial building services and suggests Class A or B for low-pressure, noncritical systems to control cost. It also warns that, across a large building, leakage can waste thousands of kilowatt-hours a year. A tighter class costs more to build and test, and the saving shows up in fan energy. The DW/144 leakage guide explains the classes.

Dampers and cleaning are recurring costs. BESA records BS 9999:2017 as requiring all fire dampers to be tested by a competent person on completion and at least annually thereafter, with more frequent checks in dusty or polluted settings. BESA also says debris in ducts obstructs airflow and makes fans work harder, which is the case for budgeting duct cleaning. Ask for commissioning to be a priced deliverable with measured airflow records, because HSE's own questions for an employer include whether mechanical ventilation is set correctly and maintained.

What does a ventilation system cost to run?

Fan electricity is airflow in litres per second, multiplied by specific fan power in watts per litre per second, divided by 1,000, multiplied by hours and by the price. DESNZ gives 24.3p per kWh for 2025 (provisional), including the Climate Change Levy, and 5.3p per kWh for gas on the same basis. The table applies the electricity price to 400 litres per second for 2,600 hours (10 hours a day, five days a week, 52 weeks).

Specific fan power for the whole system	Fan power	Electricity a year	Cost at 24.3p
0.23 W per l/s (the extract-only unit limit, unit only)	0.09 kW	239 kWh	£58
0.5 W per l/s (assumed)	0.20 kW	520 kWh	£126
1.0 W per l/s (assumed)	0.40 kW	1,040 kWh	£253
2.0 W per l/s (assumed)	0.80 kW	2,080 kWh	£505

The regulation's limit covers the internal components of the unit only, so ductwork, filters beyond the reference set and dirty or leaky systems push the whole-system figure higher. The assumed rows show the sensitivity, not typical values. A heat-recovery unit adds fan power but returns heat that would otherwise be bought at the gas price; the MVHR payback guide sets out that sum.

What should a ventilation quote itemise?

• The airflow in litres per second and the occupancy it assumes.
• The unit type and its declared data (heat-recovery efficiency, fan efficiency, filter class, sound power).
• The duct leakage class, whether it is tested, and the damper count and type.
• Controls, sensors and any link to the building management system.
• Commissioning and handover records, then the filter and cleaning regime.

Equipment, installation and controls priced as separate lines show where a difference between two bids sits. For the system types covered, see commercial ventilation and MVHR. You can send an enquiry through the form on this site.

Sources

• DESNZ annual report and accounts 2025 to 2026: performance report, GOV.UK, updated 19 August 2026, checked 22 October 2026
• Ventilation in the workplace, Health and Safety Executive, checked 22 October 2026
• Ventilation in the workplace: assessing the risk of poor ventilation, Health and Safety Executive, checked 22 October 2026
• Ventilation: Approved Document F, GOV.UK, updated 15 June 2022, checked 22 October 2026
• Commission Regulation (EU) No 1253/2014, Article 2, legislation.gov.uk, checked 22 October 2026
• Commission Regulation (EU) No 1253/2014, Annex III, legislation.gov.uk, checked 22 October 2026
• Commission Regulation (EU) No 1253/2014, Annex V, legislation.gov.uk, checked 22 October 2026
• Commission Regulation (EU) No 1253/2014, Annex I, legislation.gov.uk, checked 22 October 2026
• DW/144 Specification for sheet metal ductwork, BESA Publications, checked 22 October 2026
• Ductwork leakage classes explained, BESA, checked 22 October 2026
• Fire damper testing frequency requirements, BESA, checked 22 October 2026
• New BESA guidance will revolutionise building air quality, BESA, checked 22 October 2026

Guides on this topic

• Commercial extractor fans: types, sizing and costs
• Commercial MVHR: does heat recovery pay back?

Frequently asked questions

How much does a ventilation system cost?

Prices come from quotes, not an official average. The equipment is one line; ductwork, dampers, controls, electrical work and commissioning are others, and access also affects the price. Ask for each as a separate line, with the airflow and the declared efficiencies stated.

Do split air conditioners provide ventilation?

Not by themselves. HSE asks employers with recirculating systems whether they bring in some fresh air, so a split system in an occupied room may need a separate ventilation route. Price that route as its own item.

What airflow does a 20-person office need?

Using HSE’s 5 to 8 litres per second per occupant, 100 to 160 litres per second. At the 10 litres per second some building guides recommend, 200 litres per second. A designer works from the actual occupancy and activity.

Does extract-only ventilation need heat recovery?

The ecodesign regulation requires a heat recovery system with a thermal by-pass on bidirectional units, not on extract-only units. An extract-only unit therefore has no recovery, so the comparison is fan power and make-up air against the heat a bidirectional unit would return.