Ventilation for new builds, extensions and lofts in Devon

New homes, extensions and loft conversions need ventilation that meets the building regulations and is tested before sign-off. We design the system, install it at the right stage of the build, measure the airflows and provide the commissioning information building control asks for.

Across Devon the job is priced the same way wherever you are: what is fitted, how long it takes and how far we travel. Towns we cover include Newton Abbot, Exmouth, Barnstaple, Bideford and Plymouth.

New builds & extensions in Devon at a glance

Area: Devon
Towns listed: 21, largest Plymouth
Postcode districts: EX31, EX32, EX38, EX39, PL3 and PL4
Price region: South West
Survey: Free survey (UK mainland)

What the work involves

Extensions and loft conversions have their own triggers: a new wet room needs extract, a new habitable room needs background ventilation or a connection to the ducted system, and energy-efficiency work can mean the existing home needs more ventilation too. We work for self-builders, small developers, builders and architects. Fitting ducts at first fix is far cheaper than retrofitting, so it pays to involve us before the ceilings go up.

Extensions and lofts

Extract for new bathrooms and kitchens, background ventilation for new rooms.

Commissioning only

Testing and paperwork for systems installed by others.

MVHR for new builds

Design, first fix, second fix and commissioning for whole-home heat recovery.

Guide prices in Devon

Ventilation for new builds, extensions and lofts guide prices in Devon
Work	Guide price
MVHR in a new build or full renovation (fitted at first fix), 3 to 4 bedrooms (per home)	£5,150–£8,250 inc VAT
Continuous-running extract fan (dMEV) with humidity boost, flow tested (per fan)	£360–£625 inc VAT
Airflow testing and commissioning sheet for extract fans (up to 6 fans) (per home)	£150–£305 inc VAT
MVHR or MEV commissioning test, every terminal measured and recorded (per system)	£255–£410 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

Your SAP assessor has assumed a particular ventilation system
You are adding a bathroom or kitchen in an extension or loft
You are insulating and re-windowing an existing home

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

Drawings
Design
First fix
Second fix
Commission

Towns we cover in Devon

Questions about ventilation for new builds, extensions and lofts in Devon

Are prices different in Devon?

Our guide prices are adjusted by region. In Devon we use South West rates, so MVHR in a new build or full renovation (fitted at first fix), 3 to 4 bedrooms is typically £5,150 to £8,250 inc VAT per home.

Can you just test a system someone else installed?

Yes. We can commission and test systems installed by others, and report any issues we find.

Do loft conversions need ventilation?

Yes. New bedrooms need background ventilation, and a new en-suite or bathroom needs extract to outside.

Is the survey free in Devon?

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.

Which rules apply to ventilation in Devon?

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.