We have double-glazing at our house that will need replacing soon, as it is nearly 20 years old and some of it is starting to get draughty, while some of the windows have gotten jammed so cannot be opened.
What is the difference between double-glazing and triple-glazing when it comes to price, and what it actually does? Is it worth the extra outlay?
Our home is semi-detached, has three bedrooms with four bigger windows to replace, and four smaller ones.
Triple-glazing is a newer option to double-glazing that is meant to give even greater protection
Grace Gausden, This is Money, replies: Many homes now have double-glazing which adds an extra layer of protection, keeping the heat in with the added benefit of minimising outside noise.
However, those thinking to the future may opt for triple or even quadruple glazing, despite the added expense.
What are the difference between double and triple-glazing? Double-glazed windows have two sheets of glass with a gap in between, usually about 16mm.
Meanwhile, triple-glazed windows have three sheets of glass, and two gaps. This can make them better at insulating than many double-glazed windows but that does not mean it is always the case.
The most energy efficient type of glass for double and triple-glazing is low emissivity (low-E) glass, according to the Energy Saving Trust.
Low-E glass has a microscopically thin coating of metal oxide on one of the internal glass surfaces. This coating reflects heat back into the home but still lets in the light from outside.
The most energy efficient type of glass for double and triple glazing is low emissivity glass
With regards to cost, Alaskan Windows, a window installer, said customers could be looking at a significant uplift for triple-glazing as the extra pane of glass increases the weight of the window which means the other window components, such as hinges, often need to be upgraded.
Whether it is worth the extra cost is subjective, it claims, but said in its experience the nominal annual energy saving one is ‘calculated’ to make is not significant enough to justify the additional upfront costs for customers.
However, this performance gain compounds over time when taking into account energy cost inflation.
It added that whether you need double or triple-glazing can also depend on where you live.
For example, where the weather is – generally – milder in the South it is less recommended but in Northern areas, where it can often be chillier, it may be more suitable.
A spokesperson from Anglian replies: Window ratings explain energy loss or gain. Any window with an energy index rating of zero or greater, gains more energy than it loses.
Energy labels such as the British Fenestration Rating Council independently assess the performance of our windows by how much they harvest the sun’s free energy, how much they retain the sun’s free energy along with heating energy you have generated and paid for and, how much they lose energy through draughts.
Windows with a rating of B to E lose more energy through the course of a year than they generate. A rating’s and above indicates a positive energy gain over the course of a year.
If you have south facing elevations where you can maximise solar gain, then Anglian would recommend either our A rated or A+ rated double-glazed windows as they harvest more of the sun’s energy.
With north facing elevations, where you will not benefit from as much solar gain, but are looking to retain as much heat as you can, Anglian recommend their A++ Triple Glazed windows for maximum benefit, retaining more of the energy you generate inside your home.
Grace Gausden, This is Money, adds: Customers need to beware when purchasing double or triple-glazing, however, and ensure they are buying with a trusted company.
If they are a genuine window trader, they are likely to be a member of the Glass and Glazing Federation – an organisation whose members sign up to a consumer code which means that you should receive excellent customer service.
If you use one of their members to fit your windows but you are unhappy with the work, you will also be able to use their free reconciliation service. You can use the Glass and Glazing Federation’s website to find a member who works in your area.
When completing works, households should also ensure they have the correct planning permission as some rules state no changes can be made to certain homes.