Double Glazed UPVC Windows Glass Efficiency

In a time when we are all tightening our purse-strings, the initial cost of Double Glazed UPVC Windows and doors can often be the main decision driver when making a purchase. However, with inefficient windows and doors responsible for as much as 25% of a property’s heat loss, it can be extremely beneficial to consider their long-term investment, namely through careful consideration of their efficiency.

Double Glazed UPVC WindowsBesides the obvious benefit of minimising heat loss and helping to reduce household bills, energy efficient windows can also contribute to a more comfortable home with fewer draughts and cold spots as well as insulating the home against any external noise. In addition to this, it can also mean less of the annoying condensation build-up found on the inside of windows, as less heat is escaping.

The benefits are also more wide-spread, as it can help to minimise a homeowners’ carbon footprint as less fuel is required to heat the house. As a result, less carbon dioxide is emitted into the environment – which according to the Energy Saving Trust can amount to a reduction of up to 680kg per household, per year!

When investigating the efficiency of a window there are three key factors that should be taken into consideration. This includes the aforementioned heat emissions, but also how much sunlight travels through the glass (called solar gain), and how much air can escape through the window.

For this reason, it is important to not only look at the efficiency of the glass but also to ensure that the window is securely fitted by a reputable manufacturer.

How windows work and what to look for

The majority of modern properties have double glazed windows, which means the window has two sheets of glass with a slight gap between them (usually around 16mm) in order to create an insulating barrier between the property and the outside. Often this barrier is filled with a gas, such as argon, in order to further insulate and protect the window.

The most obvious factor to consider when examining the efficiency of a window is the type of glass used, as this can amount to a considerable difference in efficiency. Low emissivity glass (often referred to as Low-E) is the most efficient glass available on the market. This is because it usually has a coating of metal oxide applied (which is invisible to the eye) to an internal pane. The impact of this is that it allows heat and light in, but prevents the vast amount of heat escaping through the panes.

In addition to this, as touched upon briefly, glazed units can also be filled with gas. The most common of which is Argon. However, alternatives such as Xenon and Krypton are also being utilised where budget is less of a constraint: they are undoubtedly more efficient, but more expensive too.

The type of material used to construct the frame of the window can also contribute to its efficiency. The common misconception is that newer materials such as uPVC are the most effective material for the frame. However this is a far cry from the truth as timber is actually at better at insulating a home than uPVC and of course has additional benefits of being a much more attractive material to use.

However, it is important to note that listed buildings and properties in conservation areas tend to face greater restriction on the type of replacement window that can be specified and so it is recommended to seek expert advice before making any changes to the property. In certain cases, it may be necessary to seek planning permission in addition to the above.

Whilst cost is undoubtedly an important factor when committing to new windows, it’s also of paramount importance to consider the long-term value of the window in question, through careful consideration of its efficiency.

Finally, don’t forget the resale value of a property too: installing low quality windows now could lead to a loss in the final sale price at a later date, so see more information and get free quotes at

Cheap Double Glazed UPVC Windows