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What is a Low-E Coating?

Choosing new windows can often be a purely aesthetic endeavour as they undoubtedly improve the appearance of your home both inside and out. The other most important factor to consider is always how they perform, especially in relation to energy efficiency. We thought we’d take some time to explain the science behind the ‘low emissivity-coating’ technique used to ensure our glass gives the best possible performance long term, as well as looking good.

Energy saving from the outset

The immediate ideas around new windows and energy efficiency mostly concentrate on the whole unit provided. A full box replacement immediately cuts out the drafts older windows tend to have. The glass discussion comes soon after, albeit with two main stipulations – energy saving potential and noise reduction.

Focusing on the energy saving potential opens up a whole new world of possibilities, and at Core we make it our business to stay up to date with the best methods and techniques in the industry used to produce high-quality glass for our customers. After a great deal of careful research, we decided to source all of our double glazed units from Guardian, a manufacturer and world leader in high-performance glass and experts in specialist glazing and reducing emissivity.

Reducing Emissivity

Emissivity is the process or ratio of the energy emitted from the surface of a material, in this case, glass. All materials absorb, reflect and emit radiant energy, it’s a natural process and some materials emit more energy than others. At the lower end of the scale of thermal emissivity you have silver and tinfoil, and at the higher end you have glass and limestone.

As glass is so highly thermally emissive, older windows (especially those with single pane glass) cannot only let the cold in, but they also let heat escape out, meaning either lots of extra jumpers or an expensive heating bill. Recently, techniques have been developed to coat the glass with a low emissive coating in order to lower the emissivity. This is completely unnoticeable to anyone looking, however what the low e-coating effectively does is render your glass as effective as silver when it comes to low emissivity.

This coating technique then ensures the glass is optimised for energy efficiency and helps to retain thermal energy by reflecting heat back to its source. In the winter months this will be your rooms and radiators, and in the summer this will back outside to the sun. This means it works effectively both ways, whatever the season.

Saving money, energy and the planet

Whilst this will have a marked impact on your energy bills, the residual benefits of choosing low e-coated glass are more obvious in the wider context of energy efficiency globally. Using ClimaGuard double glazed units with a low emissivity coating could potentially reduce the amount of energy lost through your windows alone by up to 75%. Now imagine that on a larger scale on every one of your home’s windows and things start to get interesting.

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