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What is the Purpose of Low-E Glass?

What is the Purpose of Low-E Glass?

The quality of a window’s glass is of utmost importance. These days homeowners are obsessed with window replacement & upgrade since studies show the positive influence quality windows have on energy efficiency and home functionality. If you have an old wooden window with single pane glass and without Low-E coatings, you don’t have a properly insulated home, resulting in higher electrical bills, higher UV damage and significantly reduced comfort.

What is Low-E?

Window glass has the main role in heat transfer between your interior and the outside environment. Glass absorbs heat and reflects as little as possible. This results in disruption of ideal temperatures on the inside. To solve this problem, experts invented Low-E which stands for low-emissivity. This is a coating applied to the window glass. Its main role is to catch solar heat from the outside and reflect it, not letting it enter the home. Low-E reflects interior heat on the inside as well, keeping temperature forces separated and with minimum interaction.

With having Low-E glass, you maintain ideal temperatures at home, increasing efficiency and reducing the need for additional heating and cooling systems. The best Low-E windows retain heat, but also provide a comfortable amount of natural light on the inside.

Types of Low-E

There are 2 main types of Low-E glass: hard coat and soft coat. Each is applicable in different environments. For instance, hard coat works best for extremely cold climates since it lets some radiation pass through and heats up the house. The soft coat is recommended for hot or hot-to-cold climates, providing maximum UV protection and heat retention. The first one is also known as passive, while the second as solar control.

  • Hard-coat: A pyrolytic coating applied to the glass ribbon, fused with a glass surface. The manufacturing process creates a highly durable and strong connection.
  • Soft-coat: MSDV means magnetron sputtering vapor deposition. It is the process of creating soft-coat low-e. The coating is applied to the glass before it is cut. This Low-e is more solar efficient than hard-coat.

Additional Ratings

When choosing a window, one must not focus only on Low-E since its functionality depends on other values and glass characteristics. Here are some of the glass efficiency ratings you should know:

  • SHGC: When looking for Low-E glass, you should also mind SHGC. It is an acronym for solar heat gain coefficient and it represents the amount of solar radiation a window lets pass through. Higher numbers are better for homes facing North since they need maximum heat gain, while low numbers are those enabling minimum transmission of solar heat.
  • VT: This rating represents visual transmittance. It is expressed in percentage and the higher numbers, the more visible light entering a home. Usually, when purchasing Low-E, you will find that most of them have low VT ratings.
  • U-value: This rating stands for resistance to heat loss. If the value is lower, your home will be warmer in the winter and cooler in the summer.
  • R-value: Unlike U-value, R-value needs to be as high as possible to keep a healthy living environment. It stands for the ability to absorb and retain heat.

About PM Windows

PM Windows and Doors Kitchener Waterloo is your top choice for replacement windows and replacement doors.