What are single glazed windows?
Single glazed windows comprise a single pane of glass. Specifically, the window is just one pane of glass thick, though it could be made up of many smaller panes of glass. This style of window, usually referred to as Georgian Windows, dates back to when glass production was still a cottage industry. Before the technology was developed to produce large single panes of glass, windows were built up of smaller panes joined together by wooded frames.
Single glazed windows are very much a thing of the past, though they can sometimes be found in older properties. Recently single glazing is a rarity as public demand for better insulation has made double glazing the norm.
The Drawbacks of Single Glazing
Single glazed windows come with a number of significant disadvantages:
Poor insulation
The main drawback is heat loss. A single pane does very little to retain warmth inside your home. Outdoor temperatures quickly affect indoor comfort.
No soundproofing
Single glazing also offers virtually no noise reduction. Sound travels easily through a single pane.
Weak security
These windows are fragile. They can shatter from something as simple as a stray football, offering little to no protection against break-ins.
Minimal efficiency from secondary glazing
In the 1970s and 80s, many people added a second pane on the inside to improve insulation. This raised thermal performance from ‘non-existent’ to ‘almost non-existent’. Surprisingly, some versions of secondary double glazing are still available on eBay.
Are There Any Benefits of Single Glazing?
Truthfully, not many. If a pane breaks, it’s easy to replace. Some people find the style visually appealing, especially in heritage settings. However, this is usually outweighed by the discomfort of poor thermal performance. In general, single glazing is no longer considered a practical option.
Why Is Double Glazing Better?
Double glazed windows include two panes of glass separated by a cavity filled with a noble gas. This creates a barrier that improves insulation and soundproofing.
Better materials and frames
Modern frames are stronger, better insulated, and fitted with complex locking mechanisms for increased security.
Widespread popularity
Double glazing became popular in the 70s and 80s (who remembers Ted Moult and Everest Windows?). Today, it’s the default choice in new builds and renovations.
Some limitations
Not all double glazing is perfect. Poor-quality units can suffer from seal failures, which reduce energy efficiency and cause condensation inside the unit.
Can You Use Double Glazing in Historic Windows?
Standard double glazing isn’t always suitable for listed buildings or properties in conservation areas. These settings require window upgrades that preserve the original character of the building.
Failing to obtain approval before making changes can be a criminal offence. It may result in fines, extra costs to correct the work, or even prison. If this applies to your property, see our guide to replacing windows in a conservation area.
Vacuum Glazing: The Next Step in Double Glazing
Vacuum glazing is the latest innovation. Instead of a gas-filled cavity, the gap between the panes is a vacuum. Because a vacuum contains nothing, the gap can be extremely small—less than 0.5mm.
This allows vacuum glazing to closely resemble single glazing while offering vastly better thermal and acoustic performance. That makes it more likely to be approved for use in listed buildings and conservation areas.
These are often referred to as heritage windows. For more details, visit our post: What is vacuum glazing?