Everything You Need To Know About Double Glazing

Double-glazed windows have progressed from a ‘nice-to-have’ to an essential feature in your home. From standard double glazing to bespoke styles, double-glazing can offer many benefits to both homes and businesses. In this article, we’ll cover everything you want to know from double-glazing history, right down to your commonly asked questions.

What is double glazing?

Double-glazed windows have two panes of glass, separated with a layer of normal air or, for more efficiency, a layer of argon gas. The panes are then sealed to keep the gas contained, creating an airtight, sealed unit.

A spacer bar maintains the gap between the panes and is usually made from aluminium or plastic with low heat conductivity properties. Energy-saving glass helps reduce heat loss but it can be more expensive to install.

How does double glazing work?

Double glazing is designed to slow the transfer of heat between the panes, keeping warm air in and cold air out. Air is a poor conductor of heat so trapping it between two glass panes means it is unable to circulate, leading to greatly reduced heat loss.

Over 20% of all heat loss escapes via your windows so by keeping warm air in, double-glazing improves your property insulation. This results in fewer draughts and cheaper heating bills as you may not need to heat your home as much as you would if you only had single-glazed windows.

Argon gas has around a 34% lower thermal conductivity level than air because it is denser so it acts as a better insulator. When it’s used between the panes it’s even harder for heat to escape through double-glazed windows, further improving thermal efficiency. It is also an excellent insulator of heat and is a non-flammable and ‘non-reactive’ gas. As a noble (or inert) gas, argon does not react in the presence of a flame or heat.

Energy-saving glass is even more efficient than standard double-glazing units with thermal spacer bars acting as a better insulator than standard aluminium bars.

The history of double glazing

After gaining popularity in the USA in the late 1940s, the UK began introducing double-glazed windows in the 1970s and 80s. Until then, window companies only produced single glazing.

Window specialists began using a ‘second window’ system in the mid-60s, which involved removing rotting timber windows and replacing the original window with a second layer of glass. Although this was a popular product for the time, aluminium double glazing was the next big breakthrough in the late 70s.

From the 1980s onwards, double glazing became standard for new UK homes. Although only about 8% of UK homes featured double glazing in the 70s, the concept quickly took off and now over 85% of homes in the UK are fitted with double-glazed windows.

Image of hand opening a double-glazed window.

Benefits of double glazing and low-E glass

Double glazing offers a range of benefits to your home, particularly around energy efficiency and keeping your family warm and comfortable. When combined with low-E glass, the benefits are only increased.

Keep your house comfortable

Low-E glass combined with double glazing can keep your house warm in the winter and cool in the summer. This keeps your home at a comfortable temperature year-round.

Reduce energy bills

The insulating effect of low-E glass and double glazing can reduce your energy bills each year. Preventing heat transfer through your windows, low-E coatings can reduce heat loss from the home by up to 50%.

Protect against UV rays

UV rays can damage homes and furniture, lead to peeling paint, cracked walls and a sun-bleached effect that makes furniture look faded. Low-E glass coatings reflect UV rays away from the home so it can limit the damage caused by UV light.

Keep condensation at bay

Low-E glass and double-glazing keeps the inside of the glass warmer, reducing the chance of condensation on the inside of your windows. Condensation can quickly spread and mould and dampness also pose health risks.

Less maintenance & upkeep

Low-E glass keeps windows, doors, and their surroundings safe from external weather conditions. The glass coating is also highly durable, and more resistant to scratches than standard glass alone.

More environmentally friendly

Energy-efficient glass and double-glazing is more eco-friendly because it requires less fuel to heat the home. It can be combined with other energy-efficient designs to reduce your carbon footprint on an even greater scale.

Benefits of double glazing for businesses

From a business perspective, double glazing offers many benefits from cost saving to improved security measures and works towards maintaining a comfortable working environment.

Improved security

Security concerns are one of the main issues for businesses so double glazing makes your premises much harder to break into and can deter thieves. The costs associated with upgrading to double glazing could negate any costs or losses if you were to experience a break-in.

Noise insulation

Double-glazing has soundproofing properties which is ideal for premises on busy high streets. The double-layered glass, alongside the soundproofing gases suspended in between, offers impressive noise reduction benefits. Double glazing is designed and fitted to enhance insulation, reducing noise by up to 70%.

Energy efficiency

Maximising energy efficiency efforts is essential within your business so double-glazed windows can help keep energy costs down. Double glazing works to regulate the temperatures inside your building, providing a natural balance of both cooling and insulating benefits, depending on the season.

Enhanced safety

Double glazing can help contain fire within a building or room. The double panes of glass, separated by argon gas, act as a barrier to slow the spread of damage to your business in the event of a fire.

Aesthetics

With quality double glazing, your windows should remain clear and condensation-free while reducing the risk of dampness and mould. This can improve energy efficiency and show you are up to date with improving sustainability as a business.

Image of a cafe with large double-glazed windows.

The best double-glazed windows

With so many types of windows to choose from, it can be confusing to know which style of double glazing is the best option for you. With this in mind, here are some of the most popular styles and the benefits they offer.

Double-glazed casement windows

As the most popular window style in the UK, casement windows are hard to beat. They are easy to use and open for maximum ventilation as the hinge mechanisms are smooth to operate. Some of the benefits of double-glazed casement windows include:

Easy to use
Enhanced security
Effective slanted design
A popular choice

Double-glazed bay windows

Bay windows are becoming an increasingly popular architectural revival feature of the modern home. With origins dating back to the medieval era and their use in churches and cathedrals, their popularity increased and they became a common feature within homes in the Victorian era. Double-glazed bay windows offer:

Architectural and aesthetic charm
Additional light
Expansion of the home

Double-glazed sash windows

Sash windows have been a popular feature within British architecture since the 17th century. They offer a traditional look, as the style became increasingly common during the Georgian and Victorian eras. With double-glazed sash windows, you can enjoy:

Traditional style and bespoke options
Great ventilation benefits

Of course, the ‘best’ double-glazed windows often comes down to personal choice. So, it’s worth considering your budget, style and the practicalities of your consent windows before you make a decision.

Close-up image of an open double-glazed window.

Double glazing FAQs

Can double-glazed windows be fitted from inside?

Yes, double-glazed windows can be fitted from inside, but if your frames are already fitted, it will depend on how the pane was fitted originally and what side the beading is on. When glazing any window pane into a frame, the glass panel needs to be held in place under compression, or with beading. With PVC windows, this is normally a plastic strip seen around the edges of the glass. This strip snaps the glass into place when you install double glazing, and only runs around the side of the window frame the glass was fitted from. If you can see the beading line inside your window frames, it means your glass was fitted from inside the home. If you see beading on the frames from outside the house, it means it was fitted externally. So, externally beaded frames need to be fitted from outside the home, while internally beaded frames need to be fitted from inside the home.

What is energy-efficient glass?

Energy-efficient glass is specially designed to reflect heat into the home, reducing the cost of energy bills. Instead of escaping through windows and doors, the reflected warm air is recirculated around the house. The most energy-efficient glass is called low emissivity, or ‘low-E’ glass. The emissivity of a glass refers to how well it can radiate heat energy. Normal glass has a relatively high emissivity rating, allowing 90% of thermal energy to escape through your windows and doors. Low-E glass features a microscopically thin coating applied to one side which is made from low-emissivity materials, like silver and other metallic oxides, that improve the thermal performance of the glass. These coatings are so thin and transparent that they don’t impact the amount of light that can enter the home – maintaining the original function of windows while keeping heat in. Double-glazed windows are often made with low-E glass, leading to more efficient fixtures that reap the benefits of both designs.

Who invented double glazing?

The exact origin of double glazing is often debated. Some believe it was created by American inventor C.D Haven in the 1930s but others claim it goes back as far as Victorian Scotland. As people used to rely on fires to keep warm, heat retention was notoriously difficult, especially in large houses. C.D Haven sought to fix this problem and invented an early version of double glazing called ‘thermopane’. Haven’s invention transformed homes across America and was widely adopted during the 40s and 50s before gaining popularity in the UK.

What does the future of double glazing look like?

There was once talk within the industry of triple glazing becoming the norm across the UK. However, it’s unlikely to take off anytime soon. Triple-glazed windows work the same way as double-glazing, with an extra pane of glass to create two hermetically sealed layers of gas. Although this does offer more insulation, it’s not a significant amount when compared to traditional double glazing. This means the minimal insulation gain isn’t enough to offset the much higher production costs. Triple glazing is popular in colder countries such as Norway and Sweden where homes benefit from greater insulation. In the UK, however, it’s unlikely that we’ll see an overhaul of traditional double glazing.

If you’re concerned that your windows have begun to fail, contact your local branch of Cloudy2Clear today for a free, no-obligation quote.