How Does Low-E Glass Save Energy?

Shanghai Superhouse Building Material Co., Ltd

How Does Low-E Glass Save Energy?

Energy research experts report that up to 70% of energy loss from our homes happens through windows and doors. Worse still, a more significant percentage (almost 90%) of the heat loss occurs through the glass.

Can Low-E glass reduce these percentages, and how exactly does it work? Energy efficiency is essential in saving money spent on energy bills. That is why it is necessary to buy glass with high Low-E ratings. You may want to read below to determine precisely how Low-E glass saves energy, starting with how it works and why you should only install Low-E glass on your windows and doors. But first, what exactly does it mean for glass to be Low-E glass?

What Does Low-E Glass Mean?

When you buy glass, either for windows or doors, you will often see a ‘Low-E rating’ in the description. Even when you read articles about saving energy, you must have encountered the phrase somewhere because saving energy has become one of the ways to ensure sustainability in our buildings.

Low-E means low emissivity in full. Emissivity is the amount of radiation emitted or absorbed by a surface. Low emissivity, therefore, is a characteristic that makes surfaces radiate or emit minimal amounts of radiant energy. Low-E glass minimizes the amount of infrared and ultraviolet rays that enter our homes and the amount of heat lost from the building’s interior. Unlike ordinary glass, there are very thin transparent microscopic layers in Low-E glass. These layers are responsible for reflecting away the light from the outside and reflecting in the light inside to keep the home interior from losing heat. This action keeps the temperature at home consistent.

Types of Low-E Glass Coatings

There are two types of Low-E glass coatings, namely:

● Hard Low-E coating (passive) is applied to the glass at the float line while it is being produced and infused into the glass as it cools downs. This creates a strong hence a hard coating.

● Soft Low-E coating (solar control)- soft coatings are applied to precut glass after it has cooled down. It is sealed in an insulated glass. Soft Low-E coatings offer the best solar performance control.

Measures for Low- E glass Performance.

Because the Low-E coatings are applied at different stages, each type is bound to have different effectiveness. There are various measures to determine the performance of Low-E glass coatings:

● U-Value- U-Value is a rating applied to glass based on how much heat is lost through it.

● Solar Heat Gain Coefficient (SHGC) is the fraction of incident radiation a type of glass can admit. This may be the fraction it can transmit directly, absorb or re-radiate inward. The lower the fraction, the lower amount of solar heat the glass can transmit.

● Visible Light Transmittance measures the amount of light that can pass through glass.

● Light to Solar Gain- light to solar gain is the ratio of the glass’ SHGC to its visible light transmittance (VLT) value.

Most Low-E glass ratings fall between Low-E 180, 272, and 366. Low-E 180 is excellent for passive solar applications. It prevents heat loss from inside the home in winter and heat gain to keep the home cool during summer. Low-E 272 provides comfort in all weather and reduces heat loss by about 50%. Low-E 366 ultimately offers the best energy efficiency by blocking up to 95% of the sun’s harmful rays from entering the house.

How Does Low-E Glass Work?

Low-e glass enables particular light to enter or exit interior spaces but prevents heat loss in cold weather and heat entry in warmer weather.

Since the Low-E coatings are microscopically thin, they are practically invisible and allow maximum light into a house. The coatings are also very reflective and ensure heat retention by reflecting heat into the home when it is cold and preventing heat entry when it is hot. This is only possible because they are highly selective and only allow specific light wavelengths to pass through them. The only light passing through Low-E glass is visible, but short-wave solar energy (UV rays) and long-wave infrared (heat) are reflected. Low-e glass, therefore, makes our homes more comfortable and energy-efficient.

Benefits of Low-E Glass

Low -e glass is better than ordinary plain glass. It comes with many benefits that make them the perfect choice for your next housing or renovation project.

● Heat loss reduction-Adding Low-E glass to your windows and doors reduces heat loss by 50%. This is especially advantageous in cold climates.

● Protection of fabrics and furniture- if you live in areas that receive high amounts of sunshine and have regular glass, you may have noticed the drapery and furniture color fade with time.

● Reduced energy bills- since Low-E glass prevents heat loss, you may not need to leave your radiator or furnace on for long hours, and this will significantly make your energy bills less costly. During the day or in summer, the glass will block out heat from outside, eliminating or reducing the need to switch on the fan.

● Skin protection- it is common science that UV rays cause skin damage and, in extreme cases, skin cancer. With Low-E glass, this will be the least of your worries.

With the thermal insulation Low-E glass offers, you will not need double or triple-pane windows. This can save you a lot of money when purchasing doors and windows.

The only downside of Low-E glass is that if there are so many coatings applied, the glass will appear tinted hence reducing the amount of light that comes into the interior space.

Why Install Energy Efficient Low-E Glass in Your Home

So, are Low-E glass windows or doors worth it? You may have to spend a few more dollars when you install Low-E glass, but the benefits are worth every penny, that’s for sure. The additional amount of money you add when replacing your glass will guarantee you a lifetime of energy efficiency. This also means that you will need to spend less on energy bills and replacing fabrics and furniture in your home.

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