Double Glazed Units: Costs, Value & How They Work

Double glazing provides you with a number of benefits, including reduction of heat loss and noise pollution. Besides, it is environmentally friendly because it allows reducing your carbon footprint as well as helps you keep your energy bills lower.

What’s In This Guide?

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Double glazed units are designed to provide a good level of insulation and reduce the transfer of heat between your house and the outside. Typically, they are formed of two or three panes of glass with a gap between them which is filled with air or an insulating gas. These units fit in the door or window frames with the average thickness of the glass being 3 to 10 mm.


Double Glazed Units: The Costs

There are a number of factors that can influence the price of double glazing such as; the type of glass and the material of the frames, the shape and style of the window as well as the number of double glazed units that you need installed in your house.

There are different types of materials which are used for double glazed window frames. And you can choose from aluminium, wooden and uPVC frames, with UPVC the most popular. This is mainly due to their affordability and efficiency.

Aluminium frames are stronger but suffer from increased heat conductivity and a poorer U-Value. Wooden frames provide a great aesthetic look but are more expensive. 

In terms of the shape and style of double glazed windows, the most popular options are sash and casement. In the table below we have put together some average data to give you an idea of the estimated cost based on these two types. These are ball park figures and prices from your local supplier will differ.


Double Glazed Units: Pros and Cons

As far as materials go uPVC frames are the most common and the most affordable whilst aluminium and wooden frames are slightly more expensive.  The table below shows the estimated costs for the three most popular styles of double glazed door.

The numbers included in the table are approximate prices for double glazed doors, and the actual cost may vary from house to house and will depend on your individual requirements.

The Advantages

With double glazed units, you will be reducing the amount of energy used to heat your household. And therefore, lower your carbon emission output making your house more eco-friendly.

With single glazed units installed in your home, you could be loosing up to 70% through your windows alone. Double glazed units improve your building seal and help to reduce your energy bills with the Energy Savings Trust estimating savings of between £70 and £105 (semi-detached) each year .

Double glazed units are great for the people living in busy suburban areas as they will reduce the level of outside noise by up to 60%.

Double glazing can go a long way toward increasing the EPC rating of a home, adding value and increasing your house’s attractiveness.


Modern double glazed doors and windows are very strong and a great deterent to any would be burglar. Many companies now ship units with tempered glass further increasing their strength.

The Disadvantages

The initial price is the biggest turn off for home owners, but when looked at as an investment that will pay dividends over time and keep you and your family in comfort in the mean time, the upfront costs aren’t that bad.

Double glazed units are sealed to provide insulation, and if the seal breaks, condensation can appear between the sheets of glass. Repairing broken double glazing is difficult(read expensive) and the recommended course is usually to replace the entire unit.


Double glazed units look rather modern. Therefore, if the style of your house is designed due to classical architectural tendencies, they may not match with the aesthetics of your house. However, you can find double glazing companies that deal with creating double glazed units to fit with the older houses.


Double glazed units consist of six main parts:

  • The glass panes.
  • A spacer bar is used to separate the two panes and create the insulating gap.
  • The primary seal is the air transmission main barrier.
  • The secondary seal is the adhesive material that helps hold together the components.
  • The cavity is the empty space between the parts of the unit.
  • Desiccant is usually placed between the panes of glass to absorb additional moisture.
  • Air or gas is trapped between the two panes of glass. The most commonly used types of gas are argon, krypton, xenon or dehydrated air.

Local Suppliers

If you are thinking about installing double glazed units in your home, you will need to find a trustworthy and reliable company that can offer you a top quality service. 

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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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