Double Glazed Windows

As more and more homeowners focus on improving the energy efficiency, aesthetic and security of their homes, it is no surprise that double glazed windows are often in the news. These windows are best known for their ability to reduce energy bills. Thanks to their double glass panes that are separated by air or gas that acts as insulation that prevents heat transfer. The thickness of their panes is also proven helpful in increasing security as they are not easily broken or tampered and at the same time reduce external noise.

With all the good things that can be said about double glazed windows, you are probably considering to make the switch. However, keep in mind that not all double glazed windows are created equal, with some units performing better than the others. The last thing you want is to purchase windows that will eventually fail. So to ensure you will select the right double glazed windows and save money in the long run, look for the following things.

Double Glazed Windows

Glass panes

There are several glass options for double glazed windows, including laminated, low-emissivity, tinted and toughened glass. Your choice will depend on your needs. For instance, if you want improved security, then you could either go for laminated or toughened glass. Both options are designed for durability, so when they are subjected to heavy blow or impact, they do not easily shatter. Instead, their fragments remain intact so they are least likely to cause injury.

If you are like most homeowners, though, the real reason you want to opt for double glazed windows has more to do with energy savings. In such case, you might want to opt for low-emissivity (low-E) glass, which are known for their energy efficiency. They come with microscopic metal or metallic coating that helps suppress radiant-heat out of window and may allow varying levels of natural light into the space. If you live in an area where heating is a concern, these glasses can help prevent radiant-heat transfer out of the house, while letting solar-heat in. However, where climates demand heating and cooling, low-E glass can help minimize radiant-heat loss while allowing moderate heat gain.


The frame also contributes to the overall performance of double glazed windows, especially when it comes to their ability to insulate. As such, care should be taken when selecting your framing material. Some of the most widely used frame materials include timber, aluminium and PVC. When evaluating them, be sure to look at their U-values, the rate at which heat passes through a barrier. The lower the U-value is the more efficient the frame could insulate against heat loss.


To ensure that your double glazed windows will provide sufficient protection against water infiltration and condensation and also prevent energy loss, be sure to look at their seals. High quality double glazed windows have multiple seals that help keep moisture, draughts, condensation and noise out. They should also be installed at the right places, including the perimeter where the glass and frame meets.

Gap filling

As mentioned earlier, the dual glass panes of double glazed windows are separated by either dehydrated air or inert gas that contributes to their ability to insulate and resist condensation. Between the two, dehydrated air is commonly used as it is cheaper. The physical properties of dehydrated air allow double glazed windows to transmit less heat by way of convection. Since its molecules are relatively immobile, it has lower thermal conductivity and also has lower acoustic conductivity.

If you want to achieve better energy efficiency, though, gas filling such as argon, xenon or krypton could be a good substitute for dehydrated air. Argon, for instance, has thermal conductivity that is 34% lower than dehydrated air. Although double glazed units with argon filling will cost 5% more than those filled with air, their U-value is 30% better. As such, they are excellent at minimizing heat loss and could also last for up to 25 years without losing more than 5% of their argon filling.


Of course, aesthetics can be a factor when choosing double glazed windows. After all, they will have an impact on the overall appeal of your house once they are installed. Luckily, double glazing can be adapted to a number of designs, including sash, picture frame, double-hung, casement or fixed. Hence, finding one that suits the style of your house will not be difficult. Just make sure to consider the colour scheme and overall design of your home and use them as a basis when picking your double glazed windows. By doing so, you will be able to avoid the installation of an inappropriate window style that could ruin the appearance of your property.