Positive input ventilation (PIV) in Hertfordshire

PIV is often a good fix for Hertfordshire homes with condensation on every window.

Our team is based in Great Barr, Birmingham, and we work throughout Hertfordshire, from Welwyn Garden City, Cheshunt, Hatfield, Bishop's Stortford and Watford. The survey is free for new installations on the UK mainland, and the quote that follows is fixed and in writing.

PIV in Hertfordshire at a glance

Area: Hertfordshire
Towns listed: 32, largest Watford
Postcode districts: WD5, EN3, EN7, WD1, WD17 and HP1
Price region: East of England
Survey: Free survey (UK mainland)

What positive input ventilation (PIV) involves

Loft air is usually a little warmer and drier than outside air, and the unit filters it before it comes down into the house. 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.

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.

PIV with fan upgrades

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

Guide prices in Hertfordshire

Positive input ventilation (PIV) guide prices in Hertfordshire
Work	Guide price
Positive input ventilation (PIV) loft unit, supplied and fitted (per home)	£825–£1,475 inc VAT
Wall-mounted PIV unit for a flat (core drilled through an outside wall) (per flat)	£1,050–£1,775 inc VAT
Heater module or heated PIV unit (extra over a standard unit) (extra)	£150–£310 inc VAT

Guide prices using East of England 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

Washing dried indoors makes everything worse
You have no loft but still need whole-flat ventilation (wall unit)
Streaming windows on most mornings in winter

Rules in England

In England, ventilation is covered by Part F of the Building Regulations and its guidance, Approved Document F (2021 edition). 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 Hertfordshire

Questions about positive input ventilation (PIV) in Hertfordshire

Is the survey free in Hertfordshire?

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.

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.

How long does PIV installation take?

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

Which rules apply to ventilation in Hertfordshire?

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.

Which towns in Hertfordshire do you cover?

All of Hertfordshire, including Welwyn Garden City, Cheshunt, Hatfield, Bishop's Stortford and Watford. If your town is not listed, send the postcode and we will confirm.

Tell us whether your Hertfordshire home has a loft and we can price a PIV unit before visiting.