Double Glazing Costs, Benefits & Drawbacks

Find out the pros, the cons and the things you’ll need to bear in mind when investing in double glazing with our complete guide. Double glazing is an excellent way to reduce your energy bills and minimise the level of noise from the outside world. And after adding more home insulation, it’s probably the second most popular way to improve a house’s Building Energy Rating, reduce energy bills and improve energy efficiency.

Double glazing, also known as insulated glazing, consists of two glass panes separated by a small gap filled with a layer of air or gas. The thickness of glass may vary from 3 to 10 mm, with the gap ranging between 12 and 16 mm.

What’s In This Guide?

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The air gap between the two sheets of glass, helps to keep the heat inside your premises. So, if you want to add value to your house, it may be time to consider investing in double glazing.

Increased interest in energy efficient homes means double-glazed windows have become more popular among homeowners in the UK due to their effectiveness at keeping out the cold and noise. They can significantly reduce your energy bills and are far more eco-friendly compared to single glazed units.

How Double Glazing Works

The gap between the two sheets of glass is filled with air and is perfectly sealed. It serves as an insulator and reduces the amount of cold coming into your house as well as keeping the heat inside. The circulation of air in this gap is limited therefore it slows down the transmission of heat or cold.

Filling the gap with a gas can also increase the thermal and acoustic performance of double glazing. Argon is the most widely used gas, for this purpose due to its low conductivity properties.

If you are thinking about buying double-glazed windows, there are several factors to take into account. The main points to consider are probably the cost and type.

Double Glazing Costs

There are numerous factors influencing the cost of double glazing. First of all, prices may vary due to the size and number of windows that you are planning to buy. Larger windows and a bigger number of them will raise the price. However, a lot of companies can lower the price per unit of a double-glazed door or window if you order in bulk.

Another significant factor to take into consideration is the frame material. UPVC is one of the most affordable options, and naturally, one of the most popular ones. There are other framing materials available, such as wood or aluminium. But unfortunately the price for those materials is higher, but they don’t provide any obvious benefits over uPVC except the aesthetic look.

However, you should remember that the double glazing price can’t be counted up as a fixed rate. It really depends on your specific needs and requirements. So it’s probably best to get quotes from a professional. Get them to examine your home and provide you with a more precise estimate according to the specifications of your house.

Double Glazing Window Types

The type of glazing is another factor to consider when shopping for double-glazed windows which will influence the price. There is a wide variety of styles and shapes available on the market. Here are some of the most commonly used:

Sash windows are combined with two sashes that work independently from each other and open by sliding vertically or, sometimes, horizontally.

Casement windows are attached by several hinges and open outwards or inwards, similar to a door.

Awning windows are installed at the top with the hinges, opening outwards which provides good air circulation.

Bay windows are made of three separate panels and make up sharp edges, protruding outwards of the house.

Tilt & Turn windows have two functions: opening like a door or tilting at the top to provide some ventilation. Both of these functions are controlled by the same handle.

Dual turn windows have a classic look like the sash or casement windows. However, they operate as modern tilt and turn windows allowing you to rotate them fully.

Insulated Glazing in Doors

There are several factors that can affect the price of double-glazed doors, just like with the double-glazed windows. Below we have put together some information about the types and prices for double-glazed doors.

Like windows, the price of doors with double glazing is based on the material of the frame as well as the design. UPVC is the most affordable material when it comes to the doors. Wooden and aluminium frames, on the other hand, are more expensive. Sliding patio doors are usually the cheapest while folding doors will be that bit more expensive. The most complex type of double-glazed door is bi-fold so out of these three types it will be the most expensive.

Here is an approximate cost for each type of door based on the average prices in the UK:


The Different Types of Insulated Glazing for Doors

There is also a great variety of double-glazed doors available on the market coming in different shapes, styles and design. Here are some of the most popular options:

  • Entrance Doors
  • Bi-Fold Doors
  • Patio Doors
  • French Doors

The Structure of Double Glazing

Double glazed windows consist of the five main components:

Primary sealing
Secondary sealing
Spacer bar

As I’ve mentioned previously, these windows usually contains two glass sheets. They may be annealedlaminated or tempered and some are even coloured and tinted and it’s possible to get one way mirror types too maybe you are planning to interview spies, who knows.

The Spacer Bar

There is a spacer bar installed between the two glass sheets, which creates the gap where the air or gas will be trapped therefore giving the insulation qualities to the window. The spacer usually contains a desiccant that takes in moisture so that no condensation appears in between the glass sheets.

Then, on the outside of the glass panes, there is a primary seal and on the back of the spacer bar, the secondary seal is attached. They keep extra moisture out as well as help efficiently preserve the heat.

Double Glazing: Advantages

Due to its insulating properties, these windows preserve more heat inside of your home while keeping the cold air outside. And is a cheap way to keep your property warm by lowering the loss of heat. Depending on the size of your property and the general level of insulation, double glazing can help you save hundreds each year.

These windows can reduce outside noises by 60%, so your home is quiet and peaceful. This is a particularly useful feature for the houses situated in a loud city or near a busy road.

This is an often over looked benefit, double glazing is durable and harder to break than regular windows. By installing these windows, you will increase the level of security of your house and deter burglars from breaking-in.

By upgrading your windows, you are improving the EPC rating of your home and adding equity to it. All homes must be rated by the British energy authority before being sold or rented and the better your EPC rating the more appealing your home will be on the housing market.

Double-Glazing: Disadvantages

Since double glazing provides a great level of insulation, it effectively traps the heat inside which is a big advantage during the winter months. However, it can become a problem in the summer. The sun rays will shine inside through the glass but the heat won’t be able to escape the premises easily. To help resolve this issue some customers opt for tinted panes.

Excellent European standards mean that modern double glazing and doors are sealed well, but should the sealing become damaged in one way or another, condensation may appear between the glass sheets. It is possible to repair this, although it’s not that easy and can be quiet expensive. Generally, it is recommended to replace the whole unit.

On the face of it, double glazing appears expensive when you compare it to the standard, single glazing, windows or doors. However, in the long run, it’s a valuable investment that will pay off in the future. After all, this is the type of investment you really only make once or twice in your life and it adds equity to your home.

Types of Frames and Other Options

You can find a wide variety of framing materials and glasses available on the market so you can pick the one that fits your home the best. Apart from that, you can also get a custom spacer bar and choose what kind of gas you want to fill in the gap.

  • Aluminium Frames
  • Timber Frames
  • uPVC Frames 

Types of Double Glazing


Low-E glass type is one of the most common options because it filters harmful UV and IR light while letting the sunlight through. It also helps preserve heat inside in the winter.

Tempered Glass

Tempered glass is highly durable and provides a better level of safety. If it breaks, due to its durability the risk of injuries will be reduced.

Laminated Glass

Laminated glass is a combination of two layers which improves safety and security. It is also a popular option in the UK and the UK.

Tinted Glass

Tinted glass is an excellent solution for various weather conditions. It helps reduce harmful UV rays and keeps your house cooler during the summer months. It also helps prolong the life of your indoor furniture by reducing the amount of sunlight. In addition to this, with tinted glass, you can gain a better level of privacy.

Reflective Glass

Reflective glass has a metallic coating which gives your house a modern appearance. It effectively reduces the incoming radiation and lets in the proper amount of natural light. Additionally, it helps keep the heat during the summer down and reduces the need for curtains or shades.

Double Glazing Companies in the UK

There are lots of ways to improve your home heating and reduce your energy bills. And when it comes to installing double glazing in your house, you have to be sure that you work with the right people as it is a significant investment.

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Last Updated on October 28, 2021


Author: Indra Gupta

Indra is an in-house writer with a love of Newcastle United and all things sustainable.

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