Dorchester, Dorset
Positive input ventilation (PIV) in Dorchester
Loft or wall units that gently push filtered air into the home to tackle condensation. Covering Dorchester and DT1, DT2 and DT3.
- From £825 inc VAT per home
- Free survey
Condensation in Dorchester homes usually has one of two answers: better extract fans, or PIV as well.
For positive input ventilation (PIV) in Dorchester, send us the postcode, a few photos and a rough idea of the rooms involved. We will tell you what we would fit and roughly what it costs before arranging a visit.
PIV in Dorchester at a glance
- Town
- Dorchester, Dorset
- Postcode districts
- DT1, DT2 and DT3
- Nearby
- Weymouth (7 miles), Portland (10 miles) and Bridport (14 miles)
- Price region
- South West
- Survey
- Free survey (UK mainland)
How we approach PIV in Dorchester
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.
Guide prices in Dorchester
| 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.
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 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 Dorchester
What area around Dorchester do you work in?
All of Dorset. Near Dorchester that includes Weymouth, Portland, Bridport and Blandford Forum.
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.
Do you cover Dorchester and nearby?
Yes. We cover Dorchester and nearby places including Weymouth, Portland, Bridport and Blandford Forum. Send your postcode and we will confirm.
What is the price of a PIV unit in Dorchester?
Guide prices for Dorchester use South West rates: positive input ventilation (PIV) loft unit, supplied and fitted is typically £825 to £1,450 inc VAT per home. We confirm a fixed price in writing before any work starts.
We will check the existing fans in your Dorchester home at the same visit, because PIV works best with them working.
PIV near Dorchester
More services in Dorchester
Get a guide price in two minutes
Answer a few questions for a price range, or send photos and we will come back to you with a written quote.