St Helier, Greater London
Positive input ventilation (PIV) in St Helier
Loft or wall units that gently push filtered air into the home to tackle condensation. Covering St Helier and SM1, SM4 and SM5.
- From £950 inc VAT per home
- Free survey
We fit loft and wall-mounted PIV units across St Helier, after checking the house first.
Work in St Helier follows the rules for England and finishes with a written record of what was fitted and how it was set up.
PIV in St Helier at a glance
- Town
- St Helier, Greater London
- Postcode districts
- SM1, SM4 and SM5
- Nearby
- Carshalton (1 mile), Morden (1 mile) and Mitcham (2 miles)
- Price region
- London
- Survey
- Free survey (UK mainland)
PIV for St Helier homes
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.
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 St Helier
| 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 |
These ranges use our London rates. Prices include VAT at 20%. You get a fixed written price before any work is booked.
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 that apply in England
In England, ventilation is covered by Part F of the Building Regulations and its guidance, Approved Document F (2021 edition). It sets extract rates for kitchens, bathrooms and utilities and asks for mechanical ventilation to be commissioned and recorded.
Questions from St Helier
Do you cover St Helier and nearby?
Yes. We cover St Helier and nearby places including Carshalton, Morden, Mitcham and Wallington. Send your postcode and we will confirm.
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.
What is the price of a PIV unit in St Helier?
Guide prices for St Helier use London rates: positive input ventilation (PIV) loft unit, supplied and fitted is typically £950 to £1,675 inc VAT per home. We confirm a fixed price in writing before any work starts.
Is the survey free in St Helier?
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.
Get a PIV guide price for your St Helier home online, then confirm it on a free survey.
PIV near St Helier
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