Positive input ventilation (PIV) in Greater London

If your Greater London flat has no loft, a wall-mounted PIV unit does the same job through an outside wall.

Greater London has every kind of building, from old terraces to new estates and business parks, and every job is designed around the building in front of us, not a standard kit.

PIV in Greater London at a glance

Area: Greater London
Towns listed: 216, largest Brent
Postcode districts: N14, HA4, UB9, IG3, RM6 and NW6
Price region: London
Survey: Free survey (UK mainland)

What positive input ventilation (PIV) involves

Many units have a temperature sensor that reduces the flow or switches to a heater module on cold days, so the incoming air does not feel like a draught. Flats without a loft use a wall-mounted unit that draws air from outside through a cored hole. PIV works well in houses and flats with general condensation on windows and cold walls.

PIV with fan upgrades

PIV plus humidity-controlled extract fans in the kitchen and bathroom for the most stubborn condensation.

Loft-mounted PIV

The most common option for houses with a loft. Usually fitted in half a day.

Heated PIV

A heater module tempers the incoming air in cold weather. Useful in homes where people feel draughts.

Guide prices in Greater London

Positive input ventilation (PIV) guide prices in Greater London
Work	Guide price
Positive input ventilation (PIV) loft unit, supplied and fitted (per home)	£950–£1,675 inc VAT
Wall-mounted PIV unit for a flat (core drilled through an outside wall) (per flat)	£1,200–£2,025 inc VAT
Heater module or heated PIV unit (extra over a standard unit) (extra)	£175–£355 inc VAT

Guide prices using London rates. Prices include VAT at 20%. A guide price is not a quote: we confirm a fixed price in writing first.

Common reasons people call

Black mould on window reveals and in corners of bedrooms
Musty smell in wardrobes or behind furniture
The house feels stuffy and damp rather than cold

Rules in England

English building work follows Approved Document F (2021 edition) for ventilation rates, installation and commissioning. It sets extract rates for kitchens, bathrooms and utilities and asks for mechanical ventilation to be commissioned and recorded.

How the job runs

Survey
Fixed quote
Install
Set up
Hand over

Towns we cover in Greater London

Questions about positive input ventilation (PIV) in Greater London

Are prices different in Greater London?

Our guide prices are adjusted by region. In Greater London we use London rates, so positive input ventilation (PIV) loft unit, supplied and fitted is typically £950 to £1,675 inc VAT per home.

Will PIV make my house cold?

Most units temper or reduce the flow when the incoming air is cold, and a heated unit warms it. Placed correctly on the landing, the air spreads gently rather than blowing on anyone.

Can PIV be fitted in a flat?

Yes. Flats without loft space use a wall-mounted PIV unit that draws air from outside through an outside wall.

Is the survey free in Greater London?

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.

Which rules apply to ventilation in Greater London?

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.

Send a photo of your loft hatch area and landing ceiling for a quicker Greater London quote.