Positive input ventilation (PIV) in Hampshire

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

If you are anywhere in Hampshire, send the postcode and a few photos and we will tell you what we would recommend. Towns we cover include Farnborough, Eastleigh, Winchester, Southampton and Portsmouth.

PIV in Hampshire at a glance

Area: Hampshire
Towns listed: 34, largest Southampton
Postcode districts: GU35, PO9, PO10, PO1, PO4 and SO18
Price region: South East
Survey: Free survey (UK mainland)

What positive input ventilation (PIV) involves

PIV works well in houses and flats with general condensation on windows and cold walls. It does not replace extract fans: kitchens and bathrooms still need their own extract to remove steam at source. On survey we check the loft, the landing position and the existing fans, and we tell you if PIV is not the right answer.

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.

Wall-mounted PIV for flats

Draws air from outside through an outside wall. Suits flats and homes with no loft space.

Guide prices in Hampshire

Positive input ventilation (PIV) guide prices in Hampshire
Work	Guide price
Positive input ventilation (PIV) loft unit, supplied and fitted (per home)	£875–£1,525 inc VAT
Wall-mounted PIV unit for a flat (core drilled through an outside wall) (per flat)	£1,100–£1,875 inc VAT
Heater module or heated PIV unit (extra over a standard unit) (extra)	£160–£325 inc VAT

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

When to get it looked at

The house feels stuffy and damp rather than cold
Washing dried indoors makes everything worse
You have no loft but still need whole-flat ventilation (wall unit)

Rules in England

English building work follows Approved Document F (2021 edition) for ventilation rates, installation and commissioning. For homes, it sets minimum extract rates such as 15 litres a second for a bathroom and 30 or 60 for a kitchen, and expects mechanical systems to be airflow-tested.

How the job runs

Survey
Fixed quote
Install
Set up
Hand over

Towns we cover in Hampshire

Questions about positive input ventilation (PIV) in Hampshire

Which rules apply to ventilation in Hampshire?

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.

How much does PIV cost to install?

A loft-mounted PIV unit usually costs £795 to £1,395 including VAT supplied and fitted, and £995 to £1,695 for a wall-mounted unit in a flat. A heater module adds around £145 to £295.

Does PIV really stop condensation?

PIV reduces condensation in most homes because it dilutes moist air and keeps it moving, but it works best alongside working extract fans in the kitchen and bathroom. Leaks, rising damp or a cold bridge need fixing separately.

Which towns in Hampshire do you cover?

All of Hampshire, including Farnborough, Eastleigh, Winchester, Southampton and Portsmouth. If your town is not listed, send the postcode and we will confirm.

Are prices different in Hampshire?

Our guide prices are adjusted by region. In Hampshire we use South East rates, so positive input ventilation (PIV) loft unit, supplied and fitted is typically £875 to £1,525 inc VAT per home.

Book a free Hampshire survey and we will say honestly whether PIV, extract fans or both are needed.