Is triple-glazing worth the extra cost?

2nd August 2016

Glazed Window Glazed Window

Is triple-glazing worth the extra cost?


Craig Smith, Owener Copperfield Windows, discusses the benefits of triple-glazing over and above double-glazing and asks, is it worth it?

Improving the thermal efficiency of their home is one of the main reasons that people buy new energy efficient windows and doors.  Thermally efficient windows and doors will help you maintain a comfortable year-round temperature inside your home, while cutting the cost of heating it through colder months.

But with two measures of window performance, double and triple glazed options, A++ WER ratings and ultra-low U-values, how are homeowners to make sense of it all and moreover, know that they’re getting good value for money?

Triple-glazing is an issue that brings all of these things to a head. It costs more because it uses more glass. More glass means that material costs are higher but also handling and fitting costs because it’s heavier. So the question you need to ask yourself is, ‘do the benefits of triple-glazing outweigh the costs?’

What you need to know to make an informed choice on triple-glazing

First-up, you need to know a WER from a U-Value.

A Window Energy Rating (WER) is a measure of window performance. It combines three different elements of window performance: Solar gain or how much heat the window allows into your home; and how much it lets out of it,  either through draughts or thermal transfer and heat loss – the u-value.

U-values are a measure of heat loss alone and do not account for the heat put into it through solar gain. This is a fundamental point. Double and triple-glazing will both be very effective at stopping heat loss but of the two triple-glazing will be better because it has an extra pane of glass.

Conversely, while reducing heat loss that extra pane of glass, reduces the amount of sunlight that passes into your home, reducing solar gain.

Defining which is right for your home is a question of the individual characteristics of your property,  for example aspect and not least budget! 

Innovation in glazed unit technology

There has been massive innovation in glass. This includes the use of smart low-e coatings - a one-way door for trapping and holding energy - to the use of warm-edge spacer bars. These separate the sheets of glass in double and triple-glazed units to put ‘space’ between the cold air outside and warm air inside, insulating it in the process. 

This means that double or triple glazed units both deliver significantly improved performance over and above single or even older double-glazed units delivering savings of up to £200 per year dependent on specification of new energy efficient windows and doors and those being replaced.

Triple-glazing essentially takes all of the innovations in double-glazing thermal efficiency and makes it better, this time by a ‘third’ or more, again. The trade-off is a corresponding reduction in solar gain. 

What are the benefits of triple glazing

The triple glazed windows we supply are manufactured in a new purpose designed six chamber energy efficient system, which accommodates a  44mm triple-glazed unit, achieving a u-value as low as 0.8W/m².K. This also puts our energy efficient windows way ahead of building regulations, which currently state that all new windows must achieve a minimum u-value of 1.6W/m².K.

Anything that improves the insulation value of window glass makes condensation correspondingly less likely to form. That’s why triple-glazing goes a long way to prevent internal window condensation.  

This can lead to a slight increase in external condensation because as less heat is escaping from a property the outer pane of the window can be cooler, acting as a dew point over night for moisture in the atmosphere, although this will generally clear quickly as the air outside warms with the morning.

Triple-glazing can – in the right configuration – also help to insulate from noise but again, it’s important to do your research.  Sound passes through glass laterally. If the glass used is equal thickness e.g. three panes at 4mm the sound wave reverberates through each pane in the same way.

Despite the claims of some window companies, an additional pane, won’t automatically reduce noise.   

Do I need triple-glazing for my property?

As said, this is about your individual property and your budget. If you’re property has solid walls, it’s exposed or north facing aspects are particularly exposed to the elements, you may want to consider triple-glazing or triple-glazing on part of your home – budget permitting.

But that doesn’t mean that triple-glazing is right for everyone or that double-glazing is by default not up to the job.

We have an extensive range of high performing double-glazed windows and doors which achieve the highest standards of energy efficiency, just not quite as high as our triple-glazed range.

The advantage is that double-glazed units will warm your home a little more through solar gain – not just keep the heat that you’re heating system generates in. Given the lower purchasing costs, payback times will also be shorter.

For more information email or call a member of our team for an informal chat on 02476 452688



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