Positive input ventilation (PIV) in Wiltshire

For a typical Wiltshire semi or terrace, a loft PIV unit is often the quickest way to dry the house out.

If you are anywhere in Wiltshire, send the postcode and a few photos and we will tell you what we would recommend. Towns we cover include Chippenham, Melksham, Warminster, Calne and Westbury.

PIV in Wiltshire at a glance

Area: Wiltshire
Towns listed: 14, largest Swindon
Postcode districts: SP9, SN1, SN4, SP4, SN1 and SN2
Price region: South West
Survey: Free survey (UK mainland)

What the work involves

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. It does not replace extract fans: kitchens and bathrooms still need their own extract to remove steam at source.

Wall-mounted PIV for flats

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

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.

Guide prices in Wiltshire

Positive input ventilation (PIV) guide prices in Wiltshire
Work	Guide price
Positive input ventilation (PIV) loft unit, supplied and fitted (per home)	£825–£1,450 inc VAT
Wall-mounted PIV unit for a flat (core drilled through an outside wall) (per flat)	£1,025–£1,775 inc VAT
Heater module or heated PIV unit (extra over a standard unit) (extra)	£150–£305 inc VAT

These ranges use our South West rates. Prices include VAT at 20%. You get a fixed written price before any work is booked.

Signs it is time to call us

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 Wiltshire

Questions about positive input ventilation (PIV) in Wiltshire

Which rules apply to ventilation in Wiltshire?

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 long does PIV installation take?

A loft unit is normally fitted in two to four hours, including the diffuser and electrical connection.

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.

Which towns in Wiltshire do you cover?

All of Wiltshire, including Chippenham, Melksham, Warminster, Calne and Westbury. If your town is not listed, send the postcode and we will confirm.

Are prices different in Wiltshire?

Our guide prices are adjusted by region. In Wiltshire we use South West rates, so positive input ventilation (PIV) loft unit, supplied and fitted is typically £825 to £1,450 inc VAT per home.

We will check the existing fans in your Wiltshire home at the same visit, because PIV works best with them working.