Window & double glazing installers in Hertfordshire
456 companies · 61 towns & cities
Hertfordshire has 456 active window and glazing businesses on the Companies House register. Choose a town below to see the companies listed there, or request free quotes from FENSA or Certass registered installers covering your postcode.
Why Hertfordshire homeowners are upgrading their windows
Hertfordshire took 580mm of rain and 32 frost days in 2025. Those freeze / thaw cycles lift seals, warp frames and let moisture creep in behind older glazing. 49.2% of the county's 512,590 homes were built before 1965, back when single glazing was the norm. Retrofitting those windows is usually the single biggest heat-bill saving a homeowner can make. The county also carries 8,070 listed buildings on the National Heritage List. On those homes a full window replacement is not an option and secondary glazing is usually the route.
Get 3 free quotesFree quotes below from FENSA / Certass installers active in Hertfordshire. No obligation. Most respond within 48 hours.
Sources
Weather: Open-Meteo historical archive, 2025 daily readings for Hertfordshire.Housing: ONS Census 2021 (tables TS041 households, TS044 accommodation type), aggregated across Hertfordshire's local authorities.Housing age: VOA Council Tax stock of properties (CTSOP 4.0), 2024 snapshot, billing-authority-level rows aggregated to the county.Listed buildings: Historic England, National Heritage List for England, spatial join against ONS 2021 UTLA boundaries, retrieved 2026-09-17.
Largest towns in Hertfordshire
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