For the last 40 or so years, double glazing has been a standard in UK homes. Double glazing replaced poorly insulating, outdated and rotting timber frames with uPVC ones that were designed to take a lot more environmental stress from the unpredictable UK weather. The low maintenance nature and affordable costs of uPVC frames allowed double glazing to take over from single glazing through the 1980s and become the dominant feature of modern homes today. 93% of homes in the UK have double glazing installed today, which is a massive increase from the 8% that had them in the 1970s.

which is best double or triple glazing

With modern pressures on the oil and gas industry, the entire country and the rest of the world are watching with an understandable dread as petrol prices slowly climb and the cost of heating our homes follows. With the squeeze we’re all facing with rising energy costs, it has never been more imperative to ensure that your home is properly thermally efficient to its maximum capability.

Homes without double glazing should look to get installed as quickly as possible due to how expensive an excessively cold winter should be. Whereas homes already have double glazing, there may be a new kid on the block that offers exceptional thermal efficiency.

Triple glazing has recently come to the market as the next reasonable step for UK homes to take. Triple glazing incorporates three panes of glass instead of just two, creating two insulating gaps between the glass as opposed to double glazing’s one. Logically, it makes perfect sense that our homes should start to incorporate three panes of glass to improve our thermal efficiency as the technology becomes available, but what are the main differences between double glazing and triple glazing, and are they substantial enough to warrant the upgrade?

Double Glazing

Double glazing is the current standard for homes across the country, and for a good reason. Double glazing substantially improves over single glazed windows. By having one pane of glass, the cold air from outside can invade the home with ease. Whereas the warm air from within the home equally leaves with ease. Single glazed windows are in contact with both the warm air from inside and the cold air from outside, and whilst glass is a pretty good insulating material, it does not do a great job at keeping the warm air inside for very long because of how cold the pane of glass itself can get.

This can lead to worse problems than simply leaking heat. Thermal cracking is a serious issue for glass installations that deal with changing temperatures or opposing temperatures on either side of itself. Thermal cracking occurs when the glass is trying to expand because of the heat and contracts because of the cold. The pressure from both opposing forces causes the window to crack, requiring the need for a replacement straight away.

Double glazing solved a lot of these issues. By having two panes of glass instead of one, the same pressures are not placed on the glass, greatly reducing the risk of thermal cracking, although it can still happen in extreme circumstances.

Furthermore, the insulating gap between the two panes of glass makes an exceptional amount of difference to the home’s performance in almost every way. The gas that sits in the gap will be an insulating gas, such as argon, and essentially adds a third layer (the other two being the panes of glass) that heat needs to try and escape through. So long as the seals remain in good condition, the thermal performance of the installation will produce very low U-values for its lifetime. Once the seals break, however, your window will lose performance considerably and will need replacing as soon as possible.

how much more efficient is triple glazing than double glazing

Triple Glazing

The double glazing installations that took over the market back in the 1980s are starting to show their age and require replacing. So should you make the jump up to triple glazing? The short answer is yes, but only if you have the money to spend on it.

Triple glazing features three panes of glass and, as such, has two thermally insulated gaps filled with argon as part of the installation. This creates a much larger gap between the inside and the outside and naturally provides higher levels of thermal insulation. In fact, because of the extra layers, triple glazing has consistently tested to be around 50% more thermally efficient than its double glazing counterpart, which mathematically makes sense.

When it comes to thermal efficiency, the best way to measure it is through the U-value—the lower the U-value, the better the thermal insulation:

U-Values Single-Glazing Double-Glazing Triple-Glazing
Highest 5.8 3 0.8
Lowest 5.9 1.1 0.5
Average 5.8 1.5 0.6

The table clearly shows that single glazing is by far the worst and is exceptionally outdated at this point when compared to the other two options. Double glazing’s high of three is from older double glazing units, installed back during the boom of the product in the 1980s. The majority of double glazing units are currently coming in around 1.5, with the best installers able to provide 1.1. Triple glazing is the only one that has managed to break into the zeros. Triple glazing must meet at most 0.8 to be considered a legitimate installation of triple glazing. Some companies claim to reach as low as 0.5, whilst the majority are sitting around 0.6-0.7.

The jump from single glazing to double glazing is significant when breaking down these values, a deduction of 4 units. However, the drop to triple glazing from modern double glazing is only around 0.5 to 1, a noticeable drop in improvement. So whilst triple glazing is superior, its substantially higher price point, around 20% higher, results in its worth being somewhat questionable.

When it comes down to it, triple glazing is worth it. The improvement from single to double is substantially greater than double to triple. The improvement is still there. U-values of 0.5 are impressive and will help the home’s thermal efficiency. However, an approximate 20% increase in cost is nothing to sneeze at and can push triple glazing out of a reasonable budget for most homeowners.

As time goes on, it is a pretty safe assumption that triple glazing will overtake double glazing as the standard in UK buildings. However, for the time being, it is still considered a luxury item and only needs to be approached by those who have it in their budget to afford it.

Here at Double Glazing on the Web, we’re experts in everything double glazing, and we want to make sure our customers and clients are too! We also provide accurate and quick quotes from across the industry in one easy to find place. Please feel free to use our online pricing tool to get yours today and start your next home improvement project.