Repair or replace your double glazing?
If your windows have misted up between the panes, the seal has failed — but the frames are often perfectly fine. Replacing just the glass units is a fraction of the cost of whole new windows. Tell us how many windows, the frame type and your region, and we show you both costs side by side so you can decide. Free, no sign-up.
A guide, not a quote. The ranges are typical 2025/26 UK fitted prices — supplied and fitted, inclusive of VAT — drawn from published industry averages: a reglaze is the cost of new sealed glass units fitted into your existing frames; a replacement is new windows, frames and all, removed-and-fitted with the old ones taken away and a FENSA/building-control certificate. They exclude rotten or non-standard frames, leaded or stained glass, bay-window structural posts, and shaped or conservation units. The only real number is a measured, written quote from a glazier or window fitter, and you should get at least three. Nothing you type leaves your browser.
If the frames are sound, reglazing is usually the smart money.
Misting means a failed seal, not a failed window. When you see condensation or a cloudy haze between the panes that you can't wipe away, the airtight seal around the double-glazed unit has broken and let moisture in. The frame, the hinges and the handles are usually completely fine. In that case you don't need new windows — you need new sealed glass units dropped into the frames you've got, which is the cheaper "repair" figure here.
When replacement is worth it. If the frames themselves are the problem — uPVC that's discoloured and brittle, timber that's rotten, draughts you can feel, locks that have failed, or windows so old they're single-glazed or first-generation double glazing — then new windows are the better spend. You also get the warmer, quieter, more secure A-rated glass and a fresh guarantee, and it lifts the look (and the EPC) of the house.
The frame sets the replacement price. uPVC is the cheapest and most common. Aluminium costs more but is slim and modern. Timber is the dearest, and often required on a listed or conservation-area property. Triple glazing or top-rated A++ glass adds roughly a fifth. Reglazing, by contrast, barely cares about the frame — you're only paying for the glass and the glazier's time.
Get the certificate. Replacement windows are notifiable building work. A FENSA- or CERTASS-registered fitter self-certifies and gives you a certificate — keep it, because a buyer's solicitor will ask for it. A reglaze isn't notifiable (you're not changing the window), so no certificate is needed.
Get three quotes — and beware the hard sell. National window firms are known for inflated "today only" prices; a local glazier or fitter is often half the cost for the same job. Get three written quotes on a like-for-like spec, confirm whether scaffolding and the certificate are included, and never sign on the first visit. A budget worked out in advance is your strongest defence against a pushy salesperson.
Keep your windows project in one place.
Stead's home improvements log tracks the budget against what you actually spend, holds the FENSA certificate and the window guarantee with its expiry date, and keeps the paperwork you'll want at sale time — all alongside the rest of your home's record.