A leading provider of home improvements & double glazing in Lincoln
Trying to decide between double glazed windows or triple glazed windows for your home can be a pane (quite literally). From comfort and cost to energy efficiency, there are many factors to consider, but there’s no denying either option is a worthwhile investment, especially when compared to their single glazing counterparts.
We’ve unravelled the pros and cons of these sealed glazed units, so you can get the answers you need on the great double glazing vs triple glazing debate once and for all. However, before we start comparing the two, let’s first understand what the different terms mean.
Double glazing has long been the standard for window installation in the UK since it was introduced in the 1970s. Over the next two decades, its popularity soared, and it remains the “go-to” window asset for both residential and commercial properties.
A window unit of this form consists of two panes of glass divided by a gas-filled space. This separation is achieved through a spacer bar, which creates an air gap that is then filled with an insulating gas. This helps reduce heat loss and enhance insulation.
Double glazed windows are typically manufactured with either aluminium, timber, or UPVC frames.
Triple glazing is assembled in a similar way to double glazing, but has three (rather than two) panes of glass held together in a glazing unit. What isn’t as obvious is the additional spacer bar to keep the panes separated, providing extra insulation.
The extra pane means triple glazed windows have an increased thickness of between 28 and 44mm, which is why they tend to have stronger frames to handle the extra weight. Notoriously cold Scandinavian countries such as Norway and Sweden have taken double glazing up a notch by adding an extra pane to meet their need for effective insulation in winter.
Triple glazing is now the standard in this part of Europe, but many UK window installers like us at Lincoln Windows are now including triple glazing as part of their product offerings. Not only do they successfully retain heat in winter, they also deliver coolness in summer too — music to the ears of us Brits, where long and frequent summer heatwaves are becoming the norm.
Double glazed windows and triple windows share many of the same benefits. Essentially, the extra pane sees all these benefits magnified by enhancing what is already there. Of course, there are some differences such as the cost (which we’ll cover below), but installing double glazing is a great first step to a warmer, more energy-efficient home.
Building regulations require all new windows to be at least C-rated, so installing new double glazing at the expense of old double glazed windows or single glazed windows is worthwhile. For guidance, windows are rated between A++ (the best) and E ( the worst). Increasing your home's Energy Performance Certificate (EPC) can also add value to your home, with many buyers desiring double glazed windows as a minimum when searching for their next home.
Double glazing is constructed from toughened glass, which is naturally a better insulator than a single pane of tempered glass. You’ll quickly notice a huge difference in the heat retention abilities of your home.
Double-glazed windows and their triple-glazed cousins are both very easy to maintain. A good clean twice a year with a soft cloth and either soapy water or window cleaning solution is more than sufficient. You’ll only need to up your cleaning frequency if you’re located near the coast or in a dusty area.
The main advantage of triple glazing is the level of insulation it provides. The extra pane of glass and gas-insulated space it boasts over double glazing makes it a formidable barrier against cold outside air and at preventing heat escaping your home through the windows.
Referring to the 0.8 U-value of triple glazed windows illustrates how good they are at stopping heat transmission — both from inside to outside, and outside to inside. Essentially, the lower the U-value, the more effective the insulation. Double glazing has a U-value of 1.6, meaning that triple glazing will give you an impressive, heart-warming 50% increase in heat retention. This also helps towards minimising internal condensation issues.
Another big plus for triple glazing is the security and peace of mind they offer homeowners. Three panes of extra-thick glass and the frames’ steel reinforcement present a significant barrier for any intruder, as well as being capable to withstand howling winds and harsh weather. As the panes are internally beaded, thieves will also be thwarted, should they attempt to remove the glazed units from the outside. To beef up your security even further, triple glazing systems also benefit from some of the best hardware and locking systems available on the market.
Given triple glazed windows are more complex to manufacture and use around 30 percent more materials than double glazing units, you can expect to pay 10 to 20 per cent more for the thermal efficiency of triple glazing. Triple glazing Installation is also trickier, requiring a larger workforce, which also contributes to a bigger hole in your purse or wallet.
However, just bear in mind the long-term energy savings we mentioned earlier, which will offset some of the short-term cost for triple glazed windows.
Triple glazing is best suited for properties with north-facing windows and colder, shady rooms, because of their ability to retain more heat than double glazing. As triple glazing is adept at harvesting the heat of the sun and retaining it, it can cause windows that enjoy a lot of sunlight to get too hot in the summer.
It should be said that triple glazing still typically has a lower G-value than double glazing. This relates to the amount of heat transmitted through glass from the sun’s rays, meaning triple glazing is effective at reducing solar gain and preventing overheating in homes with an abundance of windows, particularly in south and west-facing rooms.
Triple glazing windows are not always suitable for some homes, such as listed buildings or those in a conservation area. Their weight means they can be a big no-no for properties that have walls with structural issues.
Arguably the main disadvantage of triple glazing is that it lets less light in than double or single paned windows. Put simply, the more panes a window has, the less light can enter from outside.
For all its brilliance, double glazing simply can’t match the energy performance of triple glazing. The magical third pane of glass located halfway between the inner and outer panes or double glazing creates two air locks to boost the energy performance of regular double glazing by around 30%.
Energy efficiency is further enhanced by variables such as the type of air or gas used in the space between the panes. For example, an inert gas such as argon is heavier than air and works superbly as an insulator for both noise and heat. You can also choose warm edge spacer bars around the perimeter to reduce thermal bridging and different coating on the glass to reduce energy loss from the inside. Insulated frames with a good airtightness rating are also worthy of consideration.
Finally, the heightened indoor comfort naturally comes with the bonus of saving you money on your energy bills. Triple glazing usually has a rating of A++ (the highest rating), which could put an extra £235 back in your pocket every year. While it’s highly unlikely you’ll see a return on your triple glazing investment (unless you sell your property after installation), you’ll still be doing your bit for the environment. A Glassonweb study showed the CO2 savings over their lifetime outweigh the increased CO2 emissions from producing the third pane and heavier transport.
If you live near a busy road or are based in a town or city centre, your ears will thank you for getting triple glazing installed, as you’ll notice the impact they have on blocking out noise. The same goes for double glazing, with both of these window assets providing a 35 to 40 decibels reduction in noise. That’s the equivalent of diminishing outside noise to the same levels as a quiet conversion, allowing you to watch your favourite TV programme (or the footy) in peace.
You can reduce outside noise by over 50 dB if you opt for laminated glass. There is a type of safety glass specifically designed for soundproofing, where a thin layer of polyvinyl butyral resin (PVB) is placed between two glass panes.
Even though they usually have the same profile, double and triple glazed units are sealed within their frames, rendering it almost impossible to change the glazing once it’s in a frame. You would first need to break or cut into the frame, which would immediately compromise the window’s effectiveness and security.
If you want to increase the efficiency of your double glazing windows without upgrading to triple glazing, consider replacing the glass and the seal (providing the frame is still in good condition). We strongly recommend the services of a qualified professional if you choose to go down this road, as it will guarantee your safety and compliance with building specifications.
You can even work round the restrictions of owning a listed house, by using secondary glazing covers to create tighter sealed units around the frame and prevent draughts.
Triple glazing equates to a property with better insulation than double glazing, not to mention cheaper energy bells and less reliance on energy to heat your home. If the price isn’t a factor, there’s no reason not to get it.
However, double glazing provides insulation aplenty to cope with the UK’s winters, and is still a better option in south-facing and west-facing rooms, which are exposed to more sunlight than north or east-facing rooms.
Little by little, we are being encouraged to switch from double to triple glazing, with triple glazed windows gathering traction, especially in the aluminium space. Mixing and matching the two is always a great option for keeping your colder rooms warmer in winter and warmer rooms cooler in summer.
Like all windows, they need to be installed correctly, or their performance is compromised. Both double glazing and triple glazing have an average lifespan of at least 20 years, but poor installation will mean they last much less than this.
Whether you’re a self-builder coming to specify those finishing touches or a business owner looking to improve the comfort, energy efficiency, and quality of your offices, we can help you achieve your glazing goals. Don’t hesitate to contact our friendly team for a free quote, expert advice, and FENSA-approved quality installations.
Disclaimer: All images used are for illustration purposes - actual products may differ slightly
