How long do double glazed windows last?

Most double glazed windows can last 20 to 35 years. With good quality materials, a professional installation and regular maintenance, yours could last just as long.

Here’s how to extend the lifespan of your double glazing, the signs of wear to look out for and how to know when it’s time for an upgrade.

Key takeaways

• Average lifespan of double glazing: 20 to 35 years
• Frame materials, installation quality and regular maintenance all affect longevity
• Misting between the panes of glass is a sure sign of a failed seal
• Replacement becomes worthwhile when several problems appear at once

What determines how long your double glazing lasts

Quality of materials and manufacturing

With most windows, the first part to fail is the sealed unit: the panes of glass and the seal around their edge. That seal keeps moisture out and holds in the argon gas between the panes, which helps keep heat in. Made well, it can last for decades. If the manufacturing process cuts corners, it can fail far sooner.

Cheaper uPVC can prove a false investment, as lower quality units can wear out more quickly. At Emerald Windows and Doors, we only supply and install windows built for quality and longevity, so you can be confident your windows are built to last.

Window frame materials

• uPVC windows: modern frames have hollow chambers inside that trap air for better insulation. They won’t rot and are low maintenance.
• Aluminium windows: the most durable option, holding their shape well through extremes of temperature.
• Timber windows: wooden frames can last a long time with proper care but need regular exterior paint to prevent water ingress (water soaking into the wood) and rot.

Prefer the look of wood? Our timber effect range gives you that classic appearance without the upkeep. Timber effect windows are uPVC windows finished to look like wood, so they offer the same durability and low maintenance benefits as uPVC.

Installation quality

Poor installation is one of the biggest causes of early window failure. Gaps around the frame let in cold air and moisture. At Emerald, every window is fitted by our own FENSA registered installers. FENSA is a government-authorised scheme, so you can be sure your installation meets Building Regulations.

Weather conditions

Windows in an exposed location or facing direct sunlight all day face more wear. As the glass warms by day and cools at night, the air between the panes expands and contracts. This is known as thermal pumping, and over many years it slowly wears down the seal. Extreme weather adds to the strain.

Signs your double glazing is failing

• Misting between the panes: often the first sign homeowners notice. Moisture trapped inside the double glazed unit can’t be wiped away, meaning the window seal has failed.
• Draughts: cold air or more outside noise around closed windows suggests the rubber weather seals have hardened or cracked with age.
• Rising energy bills: if warm air is escaping through your windows, your heating must work harder to make up for it.
• Stiff or sagging sashes: if the opening part of the window (the sash) sticks or sags, the hinges of the window, handles or locks may be worn.
• Damaged frames: cracks, warping or soft patches in wooden windows.

Maintenance tips to extend the life of your windows

A little regular maintenance helps your double glazing last longer by catching small problems early. The routine our team recommends is simple: every few months, clean the frames and glass with mild soapy water, avoiding harsh chemicals. Once or twice a year, lubricate the hinges and locks and check the rubber seals for cracks or gaps.

Follow this simple routine and your windows will feel the benefits for years to come.

Should you repair or replace your double glazing?

When we survey older windows, we often find that the glass unit or hardware begins causing problems while the surrounding frame remains serviceable. In these cases, a single misted unit can often be replaced without changing the whole window, and worn handles, hinges and locks can be swapped too. If several windows are failing at once, replacement is the better long-term choice.

Please note that we only carry out repairs on windows Emerald has installed. If your windows were fitted by another company, our team is still happy to give honest advice on whether a repair is worth pursuing with your original installer, or if replacement makes more sense.

It’s usually time for replacement windows when:

• Your windows are over 20 years old and several units are misting
• Frames are warped, cracked or rotting
• Draughts continue after seals have been repaired
• You want better energy efficiency

Older double glazing can lose around twice as much heat as modern replacement windows, which must now meet stricter Building Regulations.

Choosing new windows with Emerald

We offer casement windows, sliding sash windows (a popular choice for period properties), tilt and turn, flush sash and heritage styles, with triple glazing available too. All our windows are A rated for energy efficiency, helping to keep your energy bills low whichever style you choose from our double glazing range.

Every installation comes with our supplier backed 20 year guarantee, for complete peace of mind.

Talk to Emerald Windows and Doors

We have been fitting uPVC, aluminium and timber effect windows across Swindon and the surrounding South West since 2004. If your windows are misting, draughty or approaching the 20 year mark, our expert team can give you honest advice on the best next step, even if that means a repair makes more sense than replacing. When it’s time for new double glazing, we’ll handle everything from survey to fitting, with our supplier backed 20 year guarantee.

• Request a free quote online
• Call our team on 01793 700 142
• Visit our Swindon showroom to see our windows