
Group G · Airtightness, thermal bridging and finishing
Trickle vents, extract fans, PIV or MVHR so a better-sealed home stays dry.
Typical price
Ventilation with insulation
£6,000–£10,000
MVHR system with airtightness works
Ask for a quoteBefore grants · updated 11 October 2026 · a survey confirms the final figure.
What it is
Trickle vents, extract fans, PIV or MVHR so a better-sealed home stays dry.
Best for: Every deep retrofit.
Who it suits
Pick your property type for a straight answer on ventilation with insulation.
Guidance only — every home is different, and a survey confirms what suits yours.
Houses
Flats and blocks of flats
Commercial and public buildings
Usually suitable Depends — a survey confirms
Materials and brands
Trickle vents, extract fans, PIV or MVHR so a better-sealed home stays dry.
Insulation brands we work with
The exact system and brand for your home are confirmed in your written quote.
Heat, bills and EPC
Draughts carry warm air straight out of a home, and thermal bridges create cold spots where heat bypasses the insulation. Sealing and fixing them reduces heat loss and makes rooms feel warmer, while controlled ventilation keeps the air healthy and the fabric dry.
See the EPC points and savings for your home in the EPC plannerU-value before and after, typical heat and bill saving, and EPC points — worked out for your property.Price
| Service | Typical range, installed |
|---|---|
| MVHR system with airtightness works | £6,000–£10,000 |
Indicative ranges for London and the South East, supplied and installed, including VAT. Updated 11 October 2026. A survey confirms your final price.
VAT on this work
Insulation installed in homes in Great Britain is zero-rated for VAT until 31 March 2027. Other parts of a job like this — such as a new roof covering, structural work or waterproofing — may be standard-rated. Your quote shows the split.What to expect
Draught-proofing is usually done in a day. Airtightness, thermal bridging and ventilation work is scheduled with the main retrofit.
Low for draught-proofing; higher where floors, linings or ceilings are opened up.
Ventilation must meet Building Regulations Part F, fire-stopping follows Approved Document B, and funded whole-house retrofit follows PAS 2035.
PAS 2035; Part F. The guarantee and certification for your job are confirmed in writing in your quote.
60-second grant check
Grant eligibility checker
About 60 seconds · plain results: likely, possibly or not eligible
Before we start
Questions
Typically £6,000–£10,000 for mvhr system with airtightness works, installed in London and the South East, including VAT and before any grant. Prices updated 11 October 2026. A survey confirms your final figure.
A better-sealed home traps more moisture from cooking, washing and breathing. Without ventilation that moisture can cause condensation and mould.
Trickle vents, extract fans, positive input ventilation (PIV) or mechanical ventilation with heat recovery (MVHR).
PAS 2035 retrofit includes a ventilation assessment, and ventilation must meet Building Regulations Part F.
Group G

Insulated lintels, reveal and cill insulation and thermal breaks that stop cold spots and mould.

Membranes, tapes, grommets and sealants at joints, service holes and floors.

Sealing doors, windows, letterboxes, hatches, floorboards and unused chimneys — every home's quick win.

Pipe lagging, cylinder jackets, radiator reflector panels and loft tank insulation.

Sound insulation in floors, party walls and ceilings.

Cavity barriers and fire-stopping installed with EWI, cavity and loft works.
Begin your project
Tell us about your home and we'll arrange a survey, then a fixed written quote — no obligation.