How do windows retain heat?

Last Updated: 5 September 2022

Residence 9 window

There are a few items in our lives that we often take for granted because they just…work. Expertly engineered items like remotes, smartphones and the internet have been developed over the years to make our lives easier. Windows are another example of this.

The first known use of a glass window has been attributed to the Romans, way back in 100 AD. In modern times, you only really take notice of windows when they’re at the end of their useful life or something has gone wrong with them. But have you ever thought about how exactly windows retain their heat?

How do windows work?

Accoya wood polished windows

Glass, by itself, is a good conductor of heat, which isn’t great for the homeowner trying to keep warm in the colder months. In fact, experts estimate that as much as 10% of the home’s total heat loss can be attributed to windows. This gave designers the challenge of figuring out ways to improve the efficiency of the modern window. Throughout the years, window manufacturers pushed to have the latest, most energy efficient windows on the market. A few key developments have the manufacturing process has drastically improved the window’s performance:

1. Introduction of double and triple glazing
2. The development of the multi-chambered window profile
3. Designing a variety of glass coating

These key developments, all working together, have come a long way in making the modern homes warm and cosy. Let’s look at how each of these developments works:

Layer(s) of inert gas in double and triple glazing

The development of double and triple glazing was an important step in the process of improving a window’s ability to retain a home’s heat. Today’s windows feature a layer of inert gas which, unlike glass, is a good insulator of heat. This means that less heat can escape the home, helping to maintain a more comfortable temperature. This layer also has a few extra benefits, including keeping noise out.

While double and triple glazing doesn’t completely block out noise from the home’s exterior, there is a noticeable improvement compared to single glazed windows. Double glazing’s efficiency can be dramatically affected by this layer of gas escaping from the window frame. A variety of factors can cause this problem, from damage to a failed seal.

Multi-chamber window profiles

uPVC window profile
In early versions of uPVC windows, steel reinforcements were a large part of the design. Steel’s natural strength provided extra support for the window frame while increasing its security.

However, the drive to be ahead of the market saw manufacturers continuing to experiment with various techniques to the window’s increase energy efficiency.

Enter the multiple chambered window design. This concept revolutionised the window’s design and provided a noticeable improvement in their efficiency.

A chamber traps a pocket of air which acts as an insulator by blocking the transfer of heat from inside the home to the outside. Incorporating several chambers not only boosts thermal efficiency, but it also improves the window frame’s structural rigidity.

Glass coating

Modern glass coatings are essentially invisible to the naked eye and can significantly improve how much heat is lost by the glass. This coating can also affect solar gain, essentially how much warmth is allowed into the home in the warmer months. The coating rejects solar radiation and can even help control glare. Additionally, glass coating provides an additional layer of strength and security to your home.

Windows in Stockport, Sale, Cheshire, Lancashire and beyond

White flush sash windowWhen looking at replacement windows, you may see the turn “U-value” mentioned a lot. U-value is a measurement of how much heat can be transferred through a structure. In the case of windows, the lower the U-value, the better the window is at retaining a home’s warmth.

According to building regulations in England, replacement windows should have a U-value of at least 1.6 W/m²K or a Window Energy Rating of Band C or better. This has led to double glazing the standard for homes across the country.

Double glazing also has the following benefits:

  • a much more comforting living environment
  • reduced energy bills
  • less reliance on artificial heating
  • a futureproofed home against the elements
  • improved temperature balancing (warmer in winter, cooler in summer)

Reddish Joinery has a wide range of uPVC, timber and aluminium windows to suit any home. The windows can be perfectly customised to complement any home and personal taste. We aren’t just double glazing experts, we also provide homes throughout the North West with a wide variety of home improvements including doors, conservatories and orangeries. For more information on any of our products or to request a free quote, give us a call on 0161 969 7474 or send us an online message.

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