FAQ – Do I need double glazing or triple glazing?

It can be difficult to choose between double glazing or triple glazing, as each carry their own benefits.

High performance glass might seem like a smart choice – but will the greater outlay deliver the results you want?

Double Glazing

Double glazing works by trapping a layer of air between two glass panes to provide extra insulation.

Triple Glazing

Triple glazing has a third sheet of glass which forms an additional barrier. Therefore helping to improve your homes thermal performance.

Triple glazing is a must if you are looking to reach low U-values, as triple glazed units have the ability to reach U-values as low as 0.6 W/m2K. Especially if you are looking to reach Passive House standards. Whereas the same window double glazed reaches U-values in the region of 1.2 W/m2K.

Thermal Performance

As well as the glass you also need to consider the U-value of the window frames, as the quality of the frames and how well they are fitted will have a big impact on the overall performance of your glazing.

If you are replacing single glazing or old double glazing, with either new double or triple glazing you will see a vast improvement when it comes to keeping the heat in your home, but with its extra layer of glass triple glazing goes one step further.

When deciding, it’s important to take the rest of your homes insulation properties into account. If your home is old and poorly insulated, then triple glazed windows won’t be as effective at cutting your energy bills.

If you home is already well insulated or you are taking steps to improve it, then cost wise triple glazing carries a benefit.


Condensation occurs when there is a sudden change in temperatures. Warm air rises, cools and loses its capacity to hold water vapor. In the home, when warm air which is full of moisture comes into contact with a window, that is cooler than it is, the warm air is unable to retain the same amount of moisture causing condensation.

Triple glazing reduces the likelihood of condensation: because it has a lower U-value, which means that there is less of a temperature difference between the glass and other areas of the house. If your home is prone to condensation, then this can be an important factor to take into account.

Glass Thickness

As triple glazing is naturally thicker due to its third pane of glass, this carries both advantages and disadvantages, which should be taken into account when deciding between the two.

Thicker glass means your home is more secure, as it’s harder to break, due to having 3 leafs of glass instead of 2. It can also be more effective at blocking out noise – however if this is your main driver, it is possible to have specially-formulated acoustic glass with double glazing, which is designed to reduce noise.

Being thicker, also means that triple glazing is heavier than double glazing. Therefore if you live in an older building, you’ll need to investigate whether your walls could take the extra weight.


Due to the extra pane of glass in triple glazing, it is more expensive. However the price gap between the two options are falling. With triple glazing, you can also save money on your energy bills, how much you will save will be very much dependent on how well insulated your home is.

If you are unsure on whether double glazing or triple glazing is best for you, book an appointment in our Exeter showroom, where you can talk to an expert about your requirements and options available.

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