MVHR duct cleaning for balanced ventilation

How often should you clean MVHR ducts and filters?

The advice from Milieu Centraal and the manufacturers is closely aligned. The difference lies mainly in who does what.

A fixed interval is a minimum. If the building is next to a busy road, if renovation work is going on or if the date of the last cleaning is unknown, plan an inspection sooner. The general guidelines are set out under ductwork cleaning schedule.

What do dirty filters and ducts do to balanced ventilation?

Dirt in an MVHR system has two effects: less air and poorer air quality. The sources are less clear about energy use, and that is worth mentioning.

• Resistance: Milieu Centraal states that dirty filters create more resistance, so the motor works harder and uses more electricity.
• Lab research: in a study in the journal Energies (2025), heavily contaminated filters gave 37 percent less supply air. Power consumption fell slightly, from 71 to 66 watts, because the airflow decreased. The biggest problem was therefore underventilation.
• Hygiene: with dirty filters, moulds and bacteria can be blown along, according to Milieu Centraal.

Whether you use more electricity depends on the fan, but you get less fresh air either way. In an office that matters: the World Green Building Council mentions 8 to 11 percent higher productivity with better indoor air quality. Why ventilation matters in workspaces is explained under cleaning office ductwork.

Supply and extract: why you treat MVHR ducts differently

In a system with extract only, the fan unit draws dirt away from the home or building. In balanced ventilation, the supply duct blows air into the room. Whatever lies in that duct reaches the occupant. That is why two things are extra important:

1. Order of work: clean the extract first, then replace the filters and then clean the supply. This prevents the new filters from filling up with dust straight away.
2. Sealing and negative pressure: while cleaning the supply, seal off the valves in the rooms and extract the loosened dust at a central point, with a HEPA filter if the unit exhausts indoors.

In non-residential buildings the heat recovery is often housed in an air handling unit. Eurovent recommends access openings on both sides of heat recovery units, filters, fans and dampers, among others, so you can inspect and clean them. What the standards say about this is covered under EN 15780 duct cleanliness.

MVHR system cleaning cost and a fictional calculation

Average prices are known for homes; for commercial buildings, cleaning contractors usually work on a bespoke basis. All amounts relate to outsourcing.

Fictional calculation. An owners' association (VvE) with 24 flats, each with its own MVHR unit, wants all ducts cleaned at the same time. At the Werkspot indication of €175 to €300 per home, that comes to €4,200 to €7,200 per round. An installer who maintains several such complexes can carry out those rounds with their own equipment; the price of a kit is on quotation. More about prices under what duct cleaning costs.

Which equipment do you use for balanced ventilation cleaning?

Balanced ventilation ducts come in many diameters and materials. Measure what you have first, then choose.

For the main ducts the Electric DC4 brushing machine for cleaning contractors works well, for short runs the PD4 duct cleaning tool. In narrow ducts with bends you use the Intelligent Airnozzle for cleaning contractors. For brush selection, see duct brush; the EPA advises soft brushes for sheet metal and duct board. Sealing and extraction are covered by negative pressure HEPA extraction. A complete overview is under duct cleaning equipment for cleaning contractors.

Step by step plan for cleaning heat recovery ducts

1. Switch off the unit and follow the manufacturer's manual for opening it.
2. Note the setting of every supply and extract valve per room and remove them.
3. Inspect both duct networks with a camera.
4. Clean the extract ducts under negative pressure.
5. Replace the filters.
6. Seal off the valve openings in the rooms and clean the supply ducts under negative pressure.
7. Check with the camera, refit the valves in their old setting and switch the unit on.
8. Record everything, with before and after photos and the date of the next filter change.

The general playbook is described under how to clean air ducts. A good habit on top of this checklist: keep one logbook per unit in which the filter changes, the valve settings and the camera images sit together. On the next visit you can then see straight away whether the contamination has increased faster than expected and whether the interval needs to change.

What can the occupant do on balanced ventilation themselves?

The occupant replaces the filters and vacuums them in between. Brink advises replacing them at least twice a year. According to Milieu Centraal you cannot maintain the unit with the motor yourself, and you have a technician clean the valves every two years. The same applies to the ducts: that is work for an installer.

Schools need extra attention. According to RVO (Netherlands Enterprise Agency), ducts in newly completed schools sometimes turn out to be contaminated with construction dust, and with decentralised ventilation the installer has to visit every classroom for the filters. See ventilation ducts in school buildings. The difference with mechanical extract is explained under cleaning MEV systems, and the general trade off under DIY air duct cleaning. Want to know which kit fits? You can duct cleaning equipment quote via the form, request a callback or send a WhatsApp message.