Sep 06 , 2022

How Does Low-E Glass Make Windows Energy Efficient?


How Does Low-E Glass Make Windows Energy Efficient?

Have you ever wondered how window glass makes your home so energy efficient? It's called Low-E glass, also known as low-emissivity glass, which helps keep heat in during the winter and out during the summer. It can dramatically reduce your heating and cooling costs while also helping protect you from sun damage and reducing your home's carbon footprint.

Low-E is made of two panes of glass separated by a gas-filled layer that allows heat to escape when it's hot outside or warm inside and lets heat in when it's cold outside or cool inside. This article has everything you need to know about how Low-E glass can help you get it done right the first time.

What Is a Low-E glass Window?

Low-E glass, or low emissivity, is a double pane window in which the inside layer has a specific chemical applied to it, making it more difficult for infrared radiation (energy) to penetrate the window and make its way into your home. This means lower temperatures, less air conditioning and heating needed during the warmer months and more thermal insulation during the cooler months.

All windows with this coating have an R-value, indicating how well they insulate. The higher the number, the better they are at insulating. Low-E coated windows range from 1-3 R values, while typical clear glass has a 1.2 R-value. There are also other factors: UV protection so that you won't see the harmful effects of sun exposure through the glass and moisture resistance.

Moisture can cause mold growth, discolouration and deterioration if it builds up behind the sealant that holds two panes together. Without those seals, condensation builds up between both panes due to temperature changes causing foggy film over time.

When homeowners experience these issues, they often deal with repairs, replacements and installation costs before finally getting it fixed. However, by investing in Low-E glass installation services now, you can save yourself all these headaches.

Types of Low-E Coatings

There are two types of Low-E coatings for windows.

1. Passive Low-E Coating

2. Solar Control Low-E Coatings

Passive Low-E Coating: The first type is a passive coating, which only blocks radiant heat from the sun and does not block solar heat. These can be applied to any window and provide significant energy savings in hot climates where the sun's rays do not need to be blocked because they don't affect indoor temperatures.

They typically cost more than solar control coatings. Still, They offer lower upfront costs because they don't require as much maintenance or upkeep over time, as well as significantly lower installation costs due to their ease of application and lack of special skills needed by installers.

Solar Control Low-E Coatings: The second type is a solar control coating, which blocks radiant heat from the sun while still allowing solar heat into your home during the winter months. It reduces glare, too, so you can enjoy an unobstructed view outside even when it's snowing.

The major downside to this type of coating is that it requires a specialized installer who knows how to apply the coating without interfering with other parts of the window frame or altering how sunlight enters your home at different times throughout the day.

How Does It Work and Make Windows Energy Efficient?

Low-E is short for low emissivity, a type of glazing that restricts the amount of heat passing through a window. The coating on the Low-E glass contains metal oxides, which create a metallic tint and reflect radiant heat out of the window. When applied to both sides of a pane, these glazings block infrared light and are often used in residential and commercial buildings.

Most have an R-value between 1.5 and 3.0 per inch of thickness when installed as a double pane with air space between them (2x4 inches). These coatings come in various performance levels depending on cost, from so-called warm to cold. Lower quality coatings will block some solar energy but have less IR energy than higher quality ones because they contain less metal oxide per square inch; this reduces their efficiency and cost.

How to Lower Your Energy Bills?

Reducing energy use is often a good idea, whether you want to lower your electricity bills or are environmentally minded. But what can you do if you need new windows and don't want to sacrifice efficiency in the process?

Adding low-E (low emissivity) glass is one of the easiest ways to reduce energy bills. This type of window will reduce heat transfer on sunny days by as much as 45%. And because less solar radiation makes it into your home, heating costs drop too.

That's a win for everyone! Low-E glass helps homeowners save money while also helping to reduce their carbon footprint. The average American spends around $2,000 yearly on heating and cooling their home. A typical replacement window with low-E coatings could save you about 10% off that bill each year. With the average lifespan of a window being 20 years, that's at least $20,000 saved.

Combine this with saving estimated 5-kilowatt hours per day over 20 years - which comes out to another $500 saved annually - and we're looking at more than $25,000 saved over the life of a single replacement window with low-E coatings.


This will give you the knowledge to make an informed decision when shopping for new windows. Understanding Low-E glass's benefits can help determine if you want to install them in your home or office building.

One big factor will be the quality of insulation already installed in your home or office, as there is a range of R values for different types of window coverings and replacement parts. Consult with professionals about installation, R values, and other factors when considering which window replacements are best for your needs.

How Does Low-E Glass Make Windows Energy Efficient?

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