Window installer leads UK — find every retrofit opportunity in your patch

Filter Retrofit Radar by glazing type "single" or "fully single-glazed" to surface them directly. The EPC records glazing type for every property at assessment — older Victorian and Edwardian terraces over-index, as do listed and conservation-area properties where past replacement work was constrained. A typical 5-mile radius around a UK postcode returns 100 to 800 single-glazed rentals depending on stock age. Add a property-age filter (pre-1920, 1920–1949) to concentrate on the highest-conversion cohort. Single-to-double glazing on a 3-bed terrace lifts the EPC by 3 to 8 points and runs £4,000 to £8,000 — a clean MEES-driven sales pitch when the property is at high D or low E. Around 10,000 FENSA-certified glazing firms in the UK, so the trade is competitive.

FENSA — Fenestration Self-Assessment Scheme — is the UK self-certification body for window and door installers. It lets a registered installer self-certify that a window or door installation complies with Building Regulations (Part L thermal performance, Part F ventilation) without needing a separate Building Control sign-off on every job. FENSA registration is functionally non-optional for any commercial UK glazing installer — without it, every job needs a full Building Control inspection, which kills your install economics. Around 10,000 FENSA-registered firms in the UK; CERTASS is the smaller alternative scheme. Retrofit Radar does not currently filter by installer-side certification, but we surface property-side filters (glazing type, glazed area, age) that match where FENSA work concentrates.

Partially. The EPC records glazing type — single, double pre-2002, double post-2002, triple — but does not always carry an installation date for windows. We filter by the type bands directly: pre-2002 double-glazing typically fails modern Part L thermal performance and is a strong replacement candidate, while post-2002 double-glazing is generally compliant. Triple glazing is filterable too but rare in the UK rental stock — under 5% of properties. Combine window-type with EPC band D-G and the "replace single-glazed" recommendation flag to surface the cleanest replacement cohort. Future versions will integrate FENSA database lookups for installation dates; that is on the v1.5 roadmap, not currently shipped.

Not directly. There is no live UK grant scheme dedicated to window replacement for private homeowners or landlords in 2026. Window upgrades are bundled into ECO4-funded whole-house packages where the recommended-measures list flags glazing, but ECO4 closes on 31 December 2026 and is restricted to low-income households. The Warm Homes Plan is expected to include glazing in some eligibility tiers but specific delivery rules are still being detailed by DESNZ. For private MEES retrofit work, glazing falls under the £10,000 landlord cost cap — meaning a £6,000 window replacement can sit alongside £4,000 of insulation within the cap before exemption rules trigger. FENSA installers should lead on the MEES deadline and the cost-cap maths rather than wait for a dedicated grant.