Double v’s Triple glazing

February 2020

Upgrading your windows to either double or triple glazing is a really worthwhile investment. Not only will replacing your old windows with more energy-efficient glazing make a significant improvement to the comfort of your home, it will also contribute to reducing your heating bills. If you’re unsure which kind of windows to choose, here are four points to consider to help decide on which option is best for you.

What’s the difference between double & triple glazing?

There are a number of differences between triple and double glazing, the first being the number of panes of glass that make up each window. Triple glazed windows have three panes, while double glazed windows have two.

Between each pane of glass, there is a gap filled with insulating gas. The gas allows the sunlight to pass through the window while cutting down on the amount of heat that can escape from the rooms inside.

Because triple glazing has two layers of this gas, the windows give better energy performance than double glazed windows. In fact, triple glazing can reduce heat loss by approximately 30% compared to double glazing so the energy savings are much higher, meaning your heating bills will be lower.

What is the orientation of your rooms?

There is an argument that suggests, upgrading south-facing windows to double glazed units is adequate. This is because of the natural solar gain to rooms that enjoy a southerly aspect. Triple glazing, however, is preferable on all other faces of the house, especially north and east facades.

Double-glazed windows can reduce heat loss by up to 75 – 80% in comparison with single-glazed windows. Triple glazing performs even better and is ideal for colder environments and exposed sites. The extra pane of glass makes triple glazed windows thicker, heavier but also more durable than double glazing.

How much do you have to spend?

Your budget will have a bearing on whether you choose double or triple glazed windows. The cost of triple glazing has come down a lot in recent years, but triple glazed windows will still be a more expensive option than double glazed windows. Do bear in mind however that the additional expense for triple glazing is an upfront cost. Triple glazed windows will offer greater savings on your heating bills over time, so you will recoup your investment.

If you have a restricted budget but are keen to have triple glazed windows, you could consider installing triple glazing on the northern and eastern elevations where there is little or no solar gain and install double glazed windows throughout the rest of the house.

Is noise an issue for you?

Whether it’s noise from the outside traffic, house alarms or other external disturbance, minimizing noise pollution is a real consideration for many homeowners. Replacing your windows to either double or triple glazing can offer sound reduction of between 31 – 32 DB. Double glazed laminated glass will offer a reduction of 37 DB and triple glazed laminated glass will give a reduction of 40 DB, making laminate glazed windows a great option if you live in a noisy area or on a busy road.


Denise O’Connor

Managing Director Optimise Design, B.Arch. RIAI RIBA
& Senator’s Expert Design Consultant
This blog post is sponsored, but the views expressed by the author are her own.

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