Ventilation for new builds, extensions and lofts in Dyfed

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.

If you are anywhere in Dyfed, send the postcode and a few photos and we will tell you what we would recommend. Towns we cover include Haverfordwest, Milford Haven, Llanelli, Ammanford and Aberystwyth.

New builds & extensions in Dyfed at a glance

Area: Dyfed, Wales
Towns listed: 6, largest Llanelli
Postcode districts: SA62, SA71, SA72, SA14, SA15 and SA18
Price region: Wales
Survey: Free survey (UK mainland)

What the work involves

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.

MEV or dMEV

Continuous extract systems where MVHR is not specified.

Extensions and lofts

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

Commissioning only

Testing and paperwork for systems installed by others.

Guide prices in Dyfed

Ventilation for new builds, extensions and lofts guide prices in Dyfed
Work	Guide price
MVHR in a new build or full renovation (fitted at first fix), 3 to 4 bedrooms (per home)	£4,700–£7,550 inc VAT
Continuous-running extract fan (dMEV) with humidity boost, flow tested (per fan)	£330–£575 inc VAT
Airflow testing and commissioning sheet for extract fans (up to 6 fans) (per home)	£140–£280 inc VAT
MVHR or MEV commissioning test, every terminal measured and recorded (per system)	£235–£375 inc VAT

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

Signs it is time to call us

A self-build with an airtightness target
Ceilings are about to be boarded
Building control has asked for a ventilation strategy or commissioning sheet

Rules in Wales

Wales has its own Part F ventilation guidance, published by the Welsh Government, and work is checked by building control. Extract rates and commissioning are checked against the Welsh guidance on every job.

How the job runs

Drawings
Design
First fix
Second fix
Commission

Towns we cover in Dyfed

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

Is the survey free in Dyfed?

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 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.

Which rules apply to ventilation in Dyfed?

In Wales, the Welsh Government's own Approved Document F (2022 edition) applies to ventilation in homes, with a new edition taking effect on 4 March 2027. Rented homes must be fit for human habitation under the Renting Homes (Wales) Act 2016, and workplaces must be ventilated under the Workplace (Health, Safety and Welfare) Regulations 1992.

Which towns in Dyfed do you cover?

All of Dyfed, including Haverfordwest, Milford Haven, Llanelli, Ammanford and Aberystwyth. If your town is not listed, send the postcode and we will confirm.