Listed building consent is mandatory before any window work begins
If you own a listed building in the UK, any work to the windows, whether repairing, replacing, or reglazing, requires listed building consent from your local planning authority (LPA). This is a legal requirement under the Planning (Listed Buildings and Conservation Areas) Act 1990 (legislation.gov.uk, 2026). The LPA assesses whether the proposed work preserves the building’s special architectural or historic interest.
Repairing existing windows to match the original materials and design often has a lighter-touch process than replacement. Historic England advises that like-for-like repairs using traditional methods may not need formal consent if they do not alter the character of the building (GOV.UK, Listed Building Consent guidance, 2026). However, any change, such as fitting modern double glazing, almost always requires full consent. Unauthorised work can result in enforcement action, including fines or a requirement to reverse the changes at your own cost.
Standard window grants from the Great British Insulation Scheme are unavailable for listed buildings
The Great British Insulation Scheme (GBIS) does not fund window replacements for listed buildings because it targets cavity-wall and loft insulation only (Ofgem, Great British Insulation Scheme guidance, 2026). Similarly, the ECO4 scheme explicitly excludes listed building windows; ECO4 funds heating and insulation measures, not glazing (Ofgem, ECO4 guidance for suppliers, 2026). The Boiler Upgrade Scheme (BUS) does not cover windows of any type (GOV.UK, Boiler Upgrade Scheme, 2026). For listed building owners, these three major grant programmes offer no financial support for window work.
The Home Upgrade Grant (HUG) and Sustainable Warmth Competition may cover secondary glazing for listed buildings
The Home Upgrade Grant (HUG) Phase 2 (2023–2025) included secondary glazing as a permitted measure for off-gas-grid homes with listed status, and the 2026 HUG Phase 3 continuation is expected to follow the same rules (DESNZ, Home Upgrade Grant Phase 2 guidance, 2023, updated 2025). Secondary glazing, a separate pane fitted inside the existing window, is the only glazing measure typically allowed under HUG for listed buildings because it does not alter the primary window or its historic fabric. Eligibility requires a household income under £31,000 and an Energy Performance Certificate (EPC) rating of D or below. The Sustainable Warmth Competition, which funds local-authority-led schemes, also supports secondary glazing for listed buildings under similar criteria (DESNZ, Sustainable Warmth Competition prospectus, 2026).
Quick numbers
| Grant/Programme | Window measure covered for listed buildings | Maximum grant value per home | Source |
|---|---|---|---|
| Great British Insulation Scheme (GBIS) | None | £0 | Ofgem, 2026 |
| ECO4 | None | £0 | Ofgem, 2026 |
| Boiler Upgrade Scheme (BUS) | None | £0 | GOV.UK, 2026 |
| Home Upgrade Grant (HUG Phase 3) | Secondary glazing only | Up to £15,000 per home | DESNZ, 2026 |
| Local authority discretionary grant | Varies (often repair or secondary glazing) | Varies | Local authority website |
How to confirm your listed building window eligibility using the MCS and TrustMark registers
If you are applying for grant-funded secondary glazing under HUG, the installer must hold MCS certification for secondary glazing. You can check the MCS register for a certified installer in your area (MCS Certified, 2026). TrustMark registration is a separate requirement for all government-funded home energy improvement schemes; verify the installer’s TrustMark record before work begins (TrustMark, 2026). For repair-only work that does not involve a grant, no MCS or TrustMark certification is needed. However, the LPA may require a listed-building specialist, and you should check their conservation accreditation through Historic England’s register (Historic England, Conservation Accredited Professionals, 2026).
The direct answer to “listed building windows uk 2026” eligibility
No UK government grant in 2026 directly covers the replacement of windows in a listed building with modern double glazing. The only grant-funded glazing option for listed buildings in 2026 is secondary glazing, available through the Home Upgrade Grant (HUG) for eligible low-income households off the gas grid (DESNZ, HUG guidance, 2026). For all other homeowners with listed building windows, the only financial help is a local-authority discretionary grant or a heritage repair grant from a body such as the National Lottery Heritage Fund (Historic England, Grants for Historic Buildings, 2026).
How to apply for a Home Upgrade Grant for listed building windows
How to verify your installer for listed building window work
Listed building consent must be secured from the LPA before any installer begins work. The LPA may require a heritage specialist, such as a conservation-accredited builder or a window specialist with experience on listed buildings. For grant-funded secondary glazing, the installer must be MCS-certified and TrustMark-registered. For repair-only work, no specific certification is mandatory, but the LPA may still recommend a specialist from Historic England’s register of conservation accredited professionals (Historic England, 2026). Always check the installer’s track record with listed buildings before commissioning any work.
Understanding listed building consent for window repairs
Frequently Asked Questions
Yes, in most cases. Like-for-like repairs using traditional methods may not need formal consent if they do not alter the character of the building, as per GOV.UK guidance. Any change to materials or design requires full consent from your local planning authority.
Fitting modern double glazing almost always requires full listed building consent, as it can alter the building's character. The local planning authority assesses whether the change preserves the special architectural or historic interest.
No standard window grants are available from GBIS, ECO4, or the Boiler Upgrade Scheme for listed buildings. The Home Upgrade Grant Phase 2 may cover secondary glazing for off-gas-grid listed homes, as per Ofgem guidance.
Unauthorised work can lead to enforcement action by the local planning authority, including fines or a requirement to reverse the changes at your own cost. This is under the Planning (Listed Buildings and Conservation Areas) Act 1990.
No, the Great British Insulation Scheme does not fund window replacements for listed buildings. It targets cavity-wall and loft insulation only, as confirmed by Ofgem guidance.
