Replacement glazing for windows, doors and conservatories, made to your measurements and delivered across the UK
FENSA Registered BS EN 1279 10-Year Warranty
Trade pricing & bulk orders
Replacement glass — sealed units made to your exact spec
Blown, misted, cracked, or just hopelessly inefficient? You almost never need to replace the whole window, door, or conservatory — in the vast majority of cases the failure is a single sealed unit, and the fix is a like-for-like (or upgraded) replacement made to your dimensions. Pane Relief supplies replacement glass for windows, doors, conservatories, and commercial glazing across the UK: double-glazed, triple-glazed, low-E A-rated, acoustic, toughened, laminated, obscure, leaded, and Georgian-bar units, all made to order in 5-14 working days. Pick the category below — or jump straight to the configurator if you already know your dimensions.
Just need to replace a failed unit
You've spotted misting between the panes, or a stress crack, or the energy bill keeps creeping. Free delivery to Bristol (BS) postcodes (£180 inc. VAT elsewhere on the UK mainland), 10-year manufacturer warranty on edge-seal integrity (BS EN 1279-2), FENSA-registered installer recommendations in your postcode, and a phone helpline (9am–5pm, Mon–Fri) to sanity-check your measurements before you order. Most stock-size sealed units ship in 5-7 working days.
Configure my unitInstaller, glazier, FM, developer
Trade accounts, tiered volume discount on 5+/20+/50+ unit orders, scheduled site delivery, priority dispatch for active jobs. UKCA-marked, BS EN 1279-compliant units with Declaration of Performance documentation shipped on request. Bespoke supply agreements for high-volume installers and FM contractors.
Trade pricing & bulk ordersWhat are you replacing the glass in?
Five top-level categories cover almost every replacement-glass scenario in UK housing and light-commercial. Pick the closest match — each tile drills into stock sizes, specs, and lead times for that category.
Window glass
Casement, sash, bay, tilt-and-turn, fixed-light, oriel, picture. Most-requested replacement category — start here for any window unit.
Door glass
Front, back, French, patio, bi-fold, composite-door inserts. Safety glass (toughened or laminated) mandatory in any pane below 1500mm.
Conservatory glass
Roof panels, side units, conservatory doors. Laminated overhead glass mandatory by BS 6262. Self-cleaning and solar-control coatings available.
Double-glazed units
Standard 24mm or 28mm argon-filled sealed units. Like-for-like replacement or single-to-double upgrade. The UK default since the 1990s.
Triple-glazed units
36mm and 44mm krypton-filled. U-values down to 0.5 W/m²K. Heat-pump-ready, Passive-House-spec, Scandinavian thermal performance.
Configure custom
Skip the categories — enter dimensions, thickness, glass spec, coatings, and safety options for a live price in under 60 seconds.
Measure twice, order once
Whatever you're replacing, the principle is the same — you want the sealed-unit dimensions (glass + edge), not the visible glass alone, and not the whole frame opening.
The universal 5-step measure
- Measure the visible glass width at the top, middle, and bottom — use the smallest of the three.
- Measure the visible glass height at the left, middle, and right — use the smallest.
- Then add 25mm to the width and 25mm to the height — that gives you the sealed-unit size.
- Measure the sealed-unit thickness with vernier callipers or a steel rule edge-on. Common values: 14mm, 20mm, 24mm, 28mm, 36mm, 44mm.
- Photograph the frame profile, the edge of the existing unit (look for a kitemark or BS EN reference), and any obscure-pattern detail. Send to the helpline for a free spec-match.
Pricing transparency
Prices include VAT. The "from" price on each product page is for the smallest stock size at base specification (typically 4mm-20mm-4mm argon-filled annealed). Larger sizes, upgraded coatings (low-E A-rated, solar-control, self-cleaning), safety specs (toughened or laminated), acoustic interlayers, triple-glazed builds, and shaped/oversized panels are priced live in the configurator. No hidden fees, no quote-only spec lock-in.
Replacement glass — common questions answered
Q: How do I know if I need a whole new window or just a new sealed unit?
If the frame is sound (no rot in timber, no warp in UPVC, no swelling, hinges and locks working, weather-seals intact) and the visible failure is in the glass — misting between the panes, a stress crack, a blown edge-seal, condensation that won't wipe — then you almost certainly just need a new sealed unit. Glass-only replacement is typically 60-80% cheaper than a full window swap and takes a glazier 30-45 minutes per opening. Email a couple of photos to the helpline if you want a free diagnosis before ordering.
Q: What's the difference between misted, blown, and cracked?
Misted means moisture has penetrated the edge-seal and condensed inside the cavity between the panes — the desiccant is saturated, the unit's thermal performance is gone, and only replacement restores it. Blown is the same failure expressed informally — the seal has "blown". Cracked is mechanical glass failure from impact, thermal shock, or settlement. All three are sealed-unit-replacement scenarios — and we make to-spec replacements for all three.
Q: How long does a sealed unit actually last?
Industry-typical edge-seal life is 20-25 years, though that varies dramatically with installation quality and exposure. South-facing units in coastal locations fail earliest (UV plus salt accelerate seal degradation); sheltered north-facing units routinely last 30 years plus. Our 10-year manufacturer warranty on edge-seal integrity (compliant with BS EN 1279-2 weathered-durability testing) reflects the lower bound of what a properly-fitted argon-filled unit should achieve.
Q: Do you ship across the UK?
Free delivery to Bristol (BS) postcodes; £150 + VAT (£180) anywhere else on the UK mainland. We deliver to the UK mainland only. Local orders go on our own van; further afield we use Palletline, and we email you your delivery day the day before.
Q: Do you fit, or supply only?
Supply only — we're a manufacturer-to-doorstep glazing supplier, not a fitter. For installation we recommend FENSA-registered glaziers in your postcode. Call the helpline on 0117 330 3057 (9am–5pm, Mon–Fri) and we'll forward two or three local recommendations, or use the contact form for a callback. Fitting is typically £80-150 per opening for a competent local glazier.
Q: What if my unit is a non-standard shape or size?
Shaped, arched, raked, radius-edged, oversized (any dimension over 1500mm), and bespoke patterns are all in scope. Send a paper template, a cardboard cut-out, or a photo with reference measurements (a ruler in shot is ideal). Lead time on shaped units is 10-14 working days; oversized rectangular panels 7-10. Email sales@panerelief.co.uk with the template or photo for a quote.
Q: Toughened or laminated — what's the difference, and when do I need either?
Toughened (BS EN 12150) is heat-treated so it shatters into small, blunt pieces on impact — required by Approved Document K for any pane below 800mm, or within 300mm of a door edge below 1500mm. Laminated (BS EN 14449) bonds two glass panes with a PVB interlayer so a broken unit stays in one piece rather than falling — required overhead (conservatory roofs) and preferred for high-security or acoustic applications. Both are supplied; the configurator flags the legally-required spec automatically based on your dimensions and location.
Q: What's the warranty? What if I get the measurements wrong?
Every unit ships with a 10-year manufacturer warranty on edge-seal integrity (BS EN 1279-2 weathered durability) and a 10-year guarantee on low-E, solar-control, and self-cleaning coatings. If a unit is mis-measured, we remake it and you pay the same price again. The free phone sanity-check exists precisely so you don't get to that stage — send a photo and the dimensions before ordering, and our team will spot-check the spec while you're on the line.
Q: What's the typical lead time?
Stock-size double-glazed units: 5-7 working days. Custom-size rectangular double glazing: 5–7 working days. Toughened or laminated safety specs: 10–14 working days. Triple-glazed builds: 10-14 working days. Shaped, arched, or oversized (any dimension >1500mm): 10-14 working days. Emergency boarding for broken glass within 24 hours is a separate service — call the helpline immediately.
Q: Can I upgrade from single-glazed to double-glazed in the same frame?
Sometimes — depends on the rebate. Old timber sash windows usually have a 6-8mm rebate built for single glazing, which won't accept a 24mm double-glazed unit without rebate modification (a competent joiner can deepen the rebate, or you can switch to a slim-profile 14mm sealed unit designed for conservation and listed-building retrofit). UPVC and aluminium frames built post-1990 are nearly always already specced for 24mm or 28mm units, so upgrades drop straight in. See our slim-profile units if the rebate is shallow.
Related guides, collections, and specifications
Not sure where to start with your replacement?
Call the helpline on 0117 330 3057 (9am–5pm, Mon–Fri), or request a quote. Trade accounts unlock live tier pricing.