---
title: "Secondary Glazing And Films"
url: https://betterhomebetterplanet.com/catalogue/secondary-glazing-and-films/
description: "Adding a second sealed layer inside existing windows without replacing them."
---

# Secondary Glazing And Films

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| »Categories[Building Envelope](https://betterhomebetterplanet.com/catalogue/building-envelope/)5[Heating, Cooling & Water](https://betterhomebetterplanet.com/catalogue/heating-cooling-water/)6[Water & Outside](https://betterhomebetterplanet.com/catalogue/water-and-outside/)4[Materials & Finishes](https://betterhomebetterplanet.com/catalogue/materials-and-finishes/)3»Project Types[Sealing and draughtproofing](https://betterhomebetterplanet.com/catalogue/air-sealing-gaps-and-cracks/)[Insulating](https://betterhomebetterplanet.com/catalogue/attic-and-loft-insulation/)[Water and pipework](https://betterhomebetterplanet.com/catalogue/hot-water-pipe-insulation/)[Planting and drainage](https://betterhomebetterplanet.com/catalogue/drainage-and-ground-levels/)[Surfaces and finishes](https://betterhomebetterplanet.com/catalogue/low-voc-paints-and-finishes/)»Quick FindJump straight to the entry that covers a common complaint.[Lower electricity bills](https://betterhomebetterplanet.com/catalogue/how-to-reduce-electricity-bill/)[Draughts](https://betterhomebetterplanet.com/catalogue/air-sealing-gaps-and-cracks/)[Cold rooms](https://betterhomebetterplanet.com/catalogue/wall-insulation-choices/)[Condensation](https://betterhomebetterplanet.com/catalogue/secondary-glazing-and-films/)[Damp at low level](https://betterhomebetterplanet.com/catalogue/drainage-and-ground-levels/)[Noise between floors](https://betterhomebetterplanet.com/catalogue/floor-underlay-and-acoustics/)[Slow hot water](https://betterhomebetterplanet.com/catalogue/hot-water-pipe-insulation/)[Summer overheating](https://betterhomebetterplanet.com/catalogue/planting-mulch-and-shade/) | BE-05Moderate · Cool, still weatherAdding a second sealed layer inside existing windows without replacing them.Section[Building Envelope](https://betterhomebetterplanet.com/catalogue/building-envelope/)ReferenceBE-05DifficultyModerateSeasonCool, still weatherTypical scopeA day for several windowsWhat it affectsWindow draughts, glass surface temperature, noiseWhat this isWhere a window is single glazed but sound, or where its frames are original and worth keeping, a second layer can be added on the room side instead of replacing the whole unit. That layer runs from a shrink-fit film on a temporary frame, through magnetic or clip-fixed acrylic panels, to a permanent slim aluminium system with its own opening lights.Telling whether your home needs itHold the back of a hand near the glass on a cold evening. If the air there is markedly colder than the middle of the room, or if condensation forms on the inside of the glass overnight, the window is a weak point. Curtains that move when the wind gets up indicate air passing the frame rather than heat passing the glass, which is a different problem worth solving at the same time.What the job involvesThe trapped layer of still air is what does the work, so the new layer has to seal around its whole perimeter. Film systems are taped to the frame or to a light timber surround and tightened with gentle heat. Panel systems need accurate measurement of each opening, since older openings are rarely square. Permanent systems are set into the reveal and need the reveal itself checked for square and for a sound fixing surface.Things to watchSeal the frame draughts first; a second layer over a leaking frame traps moving air rather than still air. Keep at least one opening light usable in each habitable room for ventilation and for escape. Where the original window has trickle vents, do not block them behind the new layer without providing ventilation another way.**More in Building Envelope:** [Air Sealing Gaps And Cracks](https://betterhomebetterplanet.com/catalogue/air-sealing-gaps-and-cracks/) · [Attic And Loft Insulation](https://betterhomebetterplanet.com/catalogue/attic-and-loft-insulation/) \| [All Building Envelope entries](https://betterhomebetterplanet.com/catalogue/building-envelope/) \| [Catalogue index](https://betterhomebetterplanet.com/catalogue/) | »Catalogue StatusThis catalogue holds **18** entries across **4** sections.Entries are written to be read and worked from. Nothing here is ordered, priced or supplied.»Start Here[Air Sealing Gaps And Cracks](https://betterhomebetterplanet.com/catalogue/air-sealing-gaps-and-cracks/)[Attic And Loft Insulation](https://betterhomebetterplanet.com/catalogue/attic-and-loft-insulation/)[Weatherstripping Doors](https://betterhomebetterplanet.com/catalogue/weatherstripping-doors/)[Thermostat Settings And Zoning](https://betterhomebetterplanet.com/catalogue/thermostat-settings-and-zoning/)[Radiator And Baseboard Care](https://betterhomebetterplanet.com/catalogue/radiator-and-baseboard-care/) |
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|  | BE-05Moderate · Cool, still weatherAdding a second sealed layer inside existing windows without replacing them. |  |
| Section | [Building Envelope](https://betterhomebetterplanet.com/catalogue/building-envelope/) |  |
| Reference | BE-05 |  |
| Difficulty | Moderate |  |
| Season | Cool, still weather |  |
| Typical scope | A day for several windows |  |
| What it affects | Window draughts, glass surface temperature, noise |  |

4 sections · 18 entries · 5 index pages

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[Building Envelope](https://betterhomebetterplanet.com/catalogue/building-envelope/)

[Heating, Cooling & Water](https://betterhomebetterplanet.com/catalogue/heating-cooling-water/)

[Water & Outside](https://betterhomebetterplanet.com/catalogue/water-and-outside/)

[Materials & Finishes](https://betterhomebetterplanet.com/catalogue/materials-and-finishes/)

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