Double or triple glazing – which is right for your home?

Whether you have started researching your new windows and doors yet or not, you may be aware from national advertising campaigns that triple glazing is now available. Triple glazed windows are something manufacturers of windows and doors have been discussing and developing for a long time, to future proof the products from increasing energy efficiency demands. However, double glazed windows and doors have also benefited from a lot of investment in the last decade, so is triple glazing actually necessary yet, and if it is, under what circumstances? This article will look at some of the pros and cons of triple glazing versus double glazing to help you make the right decision for your home.

What is double and triple glazing?

Before we get into the nitty gritty of the advantages and disadvantages of triple glazing, it’s worth explaining that as the name suggests, a triple glazed window has three panes of glass in it, compared with the two panes found in double glazing. The third pane of glass sits in the middle of the other two, all within a sealed window frame. The space between each pane is usually filled with an inert gas such as argon gas to support energy efficiency and noise reduction.

Is three better than two?

The answer to this question is actually hugely complex for a couple of reasons. Firstly, it depends on which double glazed window, and which triple glazed window you are comparing. They are not all the same. There are, in fact, some triple glazed windows with lesser components that actually perform worse than their double glazed counterparts. Be sure to check the u-values of any windows before you buy, and ask to see any certificates that prove compliance when it comes to energy efficiency.

The answer to this question also depends on the double glazed windows you are replacing and the ones you are looking to buy.  Double glazed windows have seen a huge amount of investment in the last couple of decades, so if your windows are 15+ years old, new double glazed windows may be all you need. A recent report from the Glass & Glazing Federation (GGF) explains this in more detail, but it’s worth noting that some double glazed windows can already achieve an A++ energy rating.

Triple glazing – pros

The benefits of triple glazed windows and doors include:

• Warmer in winter – by its very nature, triple glazing should be more energy efficient than double glazed windows, because it includes an extra layer of protection between you and the outside elements. It is easier to achieve the highest energy rating with triple glazing, but as previously mentioned, it can also be possible to achieve the same or better standard with double glazing.
• Cooler in summer – a triple glazed window is in essence thicker than a double glazed window, so it can help to reduce solar heat gain and keep the home cooler in the summer months.
• Additional security – another benefit of having three panes of glass in your windows, is that it is stronger and harder to break through, hence can provide additional security.  
• Sound insulation – triple glazed windows can block out more noise than a double glazed window which could prove particularly useful in areas of high noise pollution.

Triple glazing – cons

Some of the more negative points about triple glazing include:

• More expensive – as you might expect with more materials involved, triple glazed windows are more expensive than their double glazed counterparts. The extent of this price hike – sometimes as much as double the price – needs to be weighed up against the potential improvement in sound and energy efficiency.
• If manufactured properly, triple glazed windows are much heavier to handle which makes them more difficult to move around the factory, get to site and install in the home. It is also worth asking whether the window frames have been designed to handle the extra weight of the sealed unit within. Aluminium windows and doors with their inherent strength may be the best option for triple glazed windows and doors, but whatever material is used, the frames need to take account of the additional weight.  
• Higher environmental impact – just because triple glazed windows are energy efficient once installed, that doesn’t mean they are the most environmentally friendly option. The amount of embodied carbon, i.e. the amount of carbon associated with the materials, manufacture, and the lifetime of the product, can be significantly higher for triple glazed windows compared with double glazed.
• Unnecessary – this is still up for some debate, but based on our climate in the UK, many people argue triple glazed windows are simply not a necessity in the UK. If, however, your home is situated in a noisy environment, energy efficiency may not be your only concern.  

Still unsure? Talk to the experts

As with so many things when buying new windows and doors, deciding whether to opt for double or triple glazing is down to individual taste and requirements. It is always worth talking through your options with a reputable local installation company to see what is available and whether triple glazing is worth the additional expense for your circumstances. If you’re looking for peace of mind when choosing a supplier, our outline of useful questions to ask your installer before placing an order might be helpful.