Does every flat need MVHR?

No. Part F requires adequate ventilation, and MVHR is one compliant way to provide it, not the only one. Some flats use continuous mechanical extract instead. In practice airtight new build flats very often use MVHR because it meets Part F while recovering heat, but the regulations set the ventilation standard, not the specific system.

Where does the MVHR unit go in a flat?

Usually in a utility or airing cupboard, a hallway bulkhead, or a ceiling or riser void. Flats use compact or slimline units designed for tight spaces. The unit needs access for filter changes and servicing, so a buried, unreachable location is a poor choice even where it fits.

Can MVHR be retrofitted into an existing flat?

It is possible but harder than in a house, because there is limited room for ductwork and any duct crossing a compartment wall or floor must be fire protected under Approved Document B. Many existing flats are better suited to a single room heat recovery unit or continuous extract than a full ducted MVHR retrofit.

Who is responsible for a communal MVHR system?

In a block with a shared system the freeholder or managing agent normally maintains the communal plant, with costs recovered through the service charge, while residents look after anything inside their own flat. With one unit per flat, each resident maintains their own. Check the lease and the handover information for exactly where the line sits.

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MVHR in flats and apartments

MVHR is standard in new flats and apartments, because they are built airtight and still need Part F ventilation. What differs from a house is the detail: ductwork that crosses a fire compartment wall or floor needs fire dampers under Approved Document B, the unit has to be compact enough for a flat, sound between homes matters more, and a block may use one system per flat or a shared communal system.

By VentRight Editorial · Last updated 2026-07-12 · Impartial · Sourced

Can you have MVHR in a flat or apartment?

Yes. MVHR is common in modern flats and apartments and is often the ventilation designed in from the start. Flats are built airtight to meet Part L, so they need mechanical ventilation to meet Part F, and MVHR does that while recovering heat. The system is the same idea as in a house, fitted with a compact unit and with extra attention to fire and sound.

Most new apartment blocks either give each flat its own MVHR unit or, less often, run a communal system serving several flats. Either way the flat gets continuous filtered fresh air to the living spaces and extract from the kitchen and bathroom. Because a flat is a single storey and usually compact, the unit is smaller than a house unit and is sited in a utility cupboard, hallway bulkhead or ceiling void. The differences that matter are not whether MVHR works in a flat, it does, but the fire, acoustic and space detail covered below.

Sources: GOV.UK

Do MVHR ducts in a flat need fire protection?

Yes. A block of flats is divided into fire compartments designed to hold a fire back for a set time. Where MVHR ductwork passes through a compartment wall or floor it can breach that barrier, so fire dampers or fire-rated ducting are required under Approved Document B to keep the compartment sealed. This is a key difference from a house and is the responsibility of the installer and designer.

Fire compartmentation is what buys people time to escape and firefighters time to work, typically rated for 30, 60 or 120 minutes. A duct punched through a compartment line would let fire and smoke follow the duct into the next flat or the common areas unless it is protected. The protection is a fire damper that closes on heat, or fire-rated ductwork, specified to match the fire rating of the barrier it crosses. In a single house that rarely arises; in a flat it is central to the design, and it is why apartment MVHR should be designed and installed by people who understand Approved Document B, not treated as a domestic plug in job.

Sources: GOV.UK

How is noise between flats handled with MVHR?

Ductwork can carry sound between rooms and between flats if it is not designed for it. In apartments the ducting is laid out and fitted with acoustic attenuators and insulation so that the MVHR does not become a path for noise to travel, alongside the sound separation the building already needs under Approved Document E. A well designed flat system is quiet and does not let you hear the neighbours through the vents.

Two acoustic issues come up in flats. The first is the unit and duct noise itself, handled the same way as in a house, by good duct design, avoiding cheap flexible ducting and siting the unit away from bedrooms. The second is flanking, where a shared or poorly separated duct route lets conversation or noise pass between flats. Attenuators, careful routing and keeping to the building sound insulation strategy under Approved Document E deal with it. As with fire, this is a design point that a house rarely has to worry about.

Is a communal MVHR system better than one unit per flat?

Both are used. One unit per flat is the common approach: each home controls its own ventilation and there is no shared plant to maintain or bill for. A communal system, one larger plant serving many flats, can suit some blocks but adds shared maintenance, metering and fire complexity. For most apartments an individual unit per flat is simpler and keeps control with the resident.

An individual system means each flat has its own compact MVHR unit, its own filters to change and full control over boost and background rates. A communal system centralises the plant, which can be efficient at scale but raises questions of who maintains it, how running costs are shared, and how fire and duct routing work across many compartments. In practice most new UK flats use individual units for the simplicity and resident control, with communal systems reserved for specific designs. Whichever is used, the Part F commissioning and documentation still applies.

Do flats with MVHR overheat?

Flats can be prone to overheating, especially top floor and single aspect homes with large glazing, but that is a glazing, shading and orientation issue, not an MVHR fault. MVHR with a summer bypass brings in cooler air and avoids adding recovered heat in summer, which helps, though it does not actively cool. Overheating in new homes is now assessed under Approved Document O.

Airtight flats hold heat, so the overheating risk is real, but the drivers are solar gain through unshaded glazing and limited options to open windows safely, not the ventilation system. A summer bypass stops the MVHR handing summer heat to the incoming air, and a good night time ventilation strategy helps flush heat. Where a flat genuinely overheats, the answer is shading, glazing choices and the ventilation strategy set out under Approved Document O, with MVHR as part of the solution rather than the cause. See our summer bypass guide.

Questions

Does every flat need MVHR?: No. Part F requires adequate ventilation, and MVHR is one compliant way to provide it, not the only one. Some flats use continuous mechanical extract instead. In practice airtight new build flats very often use MVHR because it meets Part F while recovering heat, but the regulations set the ventilation standard, not the specific system.
Where does the MVHR unit go in a flat?: Usually in a utility or airing cupboard, a hallway bulkhead, or a ceiling or riser void. Flats use compact or slimline units designed for tight spaces. The unit needs access for filter changes and servicing, so a buried, unreachable location is a poor choice even where it fits.
Can MVHR be retrofitted into an existing flat?: It is possible but harder than in a house, because there is limited room for ductwork and any duct crossing a compartment wall or floor must be fire protected under Approved Document B. Many existing flats are better suited to a single room heat recovery unit or continuous extract than a full ducted MVHR retrofit.
Who is responsible for a communal MVHR system?: In a block with a shared system the freeholder or managing agent normally maintains the communal plant, with costs recovered through the service charge, while residents look after anything inside their own flat. With one unit per flat, each resident maintains their own. Check the lease and the handover information for exactly where the line sits.