hand opening window

There are a number of factors that mean double and triple glazing considerably differentiate between each other, and if you are thinking of installing new windows, it’s a good time to read up on both to decide which is most suitable for you. So, Double v Triple Glazing – which is best? Well, that is for you decide. Keep reading to find out more and hopefully, come to an enlightened decision.

The Debate: Double v Triple Glazing

No new build is now built without the addition of double glazed windows; they revolutionised the technology behind windows, and now we can’t live without it. Slowly but surely, we are all being encouraged to convert to triple glazing; the pressure on switching to more energy efficient windows is only going to increase. But is it worth it?

In simple terms, triple glazing is just a step up from double glazing but is it an unnecessary and expensive adaptation that we can live without or is it well worth the investment? Most glazing products are rated on an energy-rating scale from A++ to E with A++ being the most energy efficient. If you are looking for the most energy efficient glazing, then remember to look out for the rating given.

What is Double Glazing?

Double glazing consists of two glass panes separated by a layer of air or gas. Most common gases used to fill the gap between the sheets of glass are krypton, xenon and argon. Low-E glass has an invisible coating of metal oxide around the internals panes which allows the light and heat in but prevents too much from escaping.

What Is Triple Glazing?

Triple glazing, on the other hand, is simply three panes of glass instead of 2. Theoretically, by having the third pane, both thermal and acoustic insulation is noticeably improved. The efficiency of these windows is measured by the amount of heat the material lets through; this is known as the U-value. The lower this level is, the more energy efficient the window material is. Triple glazing is known for its exceptionally low U-value.

triple glazing

Heat Penetration

Windows have much higher u-ratings in comparison to walls and doors, so it is important to ensure you have chosen windows that are as efficient as possible. If you already have older types of double glazing fitted, then the u-ratings on these windows are likely to have a U-value of 3. Newer versions are likely to be around 1.6. All new buildings are now required to be fitted with double glazing no higher than 1.6. Nevertheless, triple glazing windows will have a value no worse than 0.8 proving they retain two times more heat than double glazing does.

However, when the sun shines outside, double glazing allows the heat to enter in and helps to contribute to the overall warmth of the building. But, when a third pane is added to the window, this quality is made virtually obsolete. This is something to consider if you live in a cooler climate where the sun shines less.

Light Penetration

Double glazing is ideal for enabling the maximum amount of light into your home, however, by adding an extra pane of glass, this is significantly reduced. The reflection from the additional pane will mean the interior of the window will naturally be dimmer. opt for double glazing rather than triple if you are looking to obtain maximum light into your home.


Triple glazing is less prone to condensation build up, apart from if it occurs on the outside pane of the window; which is fairly common. This is a result of low-heat transference; moisture will settle onto the cold surface and condense because of the lack of heat from inside the outside pane. Double glazing, however, is less prone to this inconvenience.


Double glazing’s ability to exclude ambient noise is one of its principal characteristics. Double glazing is ideal if you live in a built-up area and wish to block out the noise pollution. So it would make sense that by simply adding an extra pane you could further prevent noise penetration. In actual fact, when you take into consideration the rule that sound travels much easier through a solid than it does air, it makes sense for triple glazing to perform worse than double glazing. Therefore, if you are looking for windows that perform highly when it comes to obstructing out noise pollution, it is worth avoiding triple glazing.

The Difference in Cost

Triple glazing is considerably more expensive than double glazing is. On average, to replace all of the windows in a four-bedroom house, you can expect to spend around £7,000. For slightly smaller properties, this can be anywhere from £3,000 to £5,000. However, with the improved thermal insulation qualities, you are likely to see a substantial decrease in your heating bills. For a detached property having installed A++ energy rated windows, you could save on average anywhere between £135 – £175 per year. If a mid terrace home did the same, they could save within the region of £100 just on their annual energy bills. Nevertheless, there is little point in installing triple glazed windows into a heat-porous property; to justify the cost, the building itself must be able to retain some of its own heat and be of a fairly high standard of energy efficiency.

double glazing


Triple glazing is substantially more efficient at heat retention than double glazing is and will help save costs on annual energy bills, however, the initial cost of installing triple glazing is much more considerable and means a long return on investment. Triple glazing is much less prone to condensation build up between the panes, but there is still a high chance condensation will form on the outer pains, especially in the cooler damper months.

It has to be said that triple glazing provides a much higher level of security for your home than double glazing does; the triple pane quality makes the glass much harder to break. You have to decide which of the qualities of each type of glazing will best suit your property, environment and habitat.

Overall, there are a number of negatives and crowning positives of both double and triple glazing. If you are looking for a supplier of double glazing in Milton Keynes, then take a look at what we, here at Crown Windows, have to offer.