The manufacturing of triple glazed windows is more expensive than double glazed windows. There is an additional pane of glass, an extra chamber to fill with argon gas, and an extra spacer bar. The transportation costs are also greater because of the extra weight and size.
The cost of double glazing comes to approximately £100 per square metre. This means an average 4ft square window will have around 1 square metre of glass. That results in the window costing around £100 if it has standard double glazing.
What Does a Triple Glazed Window Cost?
The exact cost will vary depending on the materials of the window frame and the system being used. However, looking at a standard white uPVC window with a few openings in double glazing, the installation cost will be around £465. If this same window was to have triple glazing, it would cost approximately 22% more at £565.
Triple Glazing and Heat Loss
Around 20% of heat in the average UK house will be lost through the windows. If you are thinking of changing your windows, you should use insulated products to have the best chance of heat retention. To determine the costs of this, you will need to consider the initial costs of triple glazing against the long-term savings in heating bills.
The pay back time for this will not be overnight and you have to consider this. A lot of people find that triple glazing allows them to live more comfortably. However, the final decision will be down to you and your financial situation.
The Benefits of Triple Glazing
There are a lot of benefits to triple glazing that you need to know. The primary one is heat insulation, but not all triple glazing is the same. There are a lot of different triple glazing systems on the market, but to get all the benefits they need to have the right internal structure.
The gap between the glass panes should be 16mm and filled with an inert gas such as argon. The argon gas will reduce the amount of heat lost through the panes. If the gap between the panes is smaller, the thermal performance will be reduced. The only time this is not true is when a more expensive gas such as krypton is used.
The best size for a triple-glazed window is 4mm thick glass and a 16mm gap. In the glazing industry, this is known as 4/16/4/16/4 units and will have a total size of 44mm. When comparing the heat loss or u-values of a 44mm triple unit and a 28mm double glazed unit, the difference will be large. The general u-value of the centre pane of the 44mm unit is 0.62 while the double-glazed unknit will be 1.1. This is an improvement of over 40%.
The Energy Rating of Triple Glazing
It is possible to choose your window based on the number of glass panes. However, you should also look at the Window Energy Rating or WER. This is a more reliable method of determining the effectiveness of the windows in terms of thermal performance. WER is the UK standard for calculating the loss of heat through a window.
This rating will take certain factors into account including:
The air loss through the window. The u-value of the window is the calculation of how thermally effective the entire window is. This will include the glass and the frame material.
The amount of heat from the sun which passes through the glass to heat your home. Triple glazing does not generally enhance the solar gain when compared to double glazing. A well insulated window will retain heat, but will not allow any solar gain.
Triple glazing will cost more than double glazing. On average this has been calculated at an increase of 22% overall. However, this is just the costs certain companies have calculated. National glazing companies, like the KJM Group, may charge more than this and smaller companies will be more affordable to ensure they are competitive. Large companies also generally offer free upgrades to triple glazing, but will not use it as the starting base product. There are a lot of strange pricing tactics being used by companies and you need to get multiple estimates to find the best choice.