As a homeowner shopping for replacement windows, you might find yourself overwhelmed by a flood of customization choices. From style, to frame color, to grids, it can be challenging to figure out which decisions are the most critical. For most homeowners, the most important decision is that of glass type. This is especially true if you’re concerned about energy efficiency (and who isn’t?), as 70% of energy loss in the home is due to windows and doors. Low-E is an innovative solution that improves energy efficiency in the home.
To understand the benefits of Low-E glass windows and what makes them energy efficient, we’ll cover:
What are Low-E glass windows & what makes them energy efficient?
Put simply, Low-E glass keeps unwanted light rays from entering the home, while preventing interior heat and air conditioning from exiting. It does all of this without blocking natural light from passing through.
To really understand how this energy efficient window coating works, we need to first explore the solar energy spectrum and the types of light involved. The three important light rays we’ll discuss are ultraviolet (UV) light, visible light, and infrared light. These light rays all occupy different parts of the solar energy spectrum, and are differentiated by their respective wavelengths.
While this may seem like an unasked for science lesson, the knowledge of these three light types is critical to understanding the benefits of Low-E windows. Another key concept is emissivity, which is how well a material radiates energy. When it comes to windows, the lower the emissivity, the higher the energy efficiency. That’s where low emissivity (or Low-E) coating factors in.
This coating, which is thinner than a strand of hair, limits the emissivity of the glass. Low-E glass prevents ultraviolet and infrared light from passing through the glass, into the home. At the same time, it maintains a stable temperature in your home by reflecting interior heat energy (whether it’s cool or warm), back inside.
All of these factors make these windows extremely energy efficient. For one, they prevent solar heat from entering the home, which means less of a need for air conditioning in the warmer months. Additionally, the reflective insulation properties cause them to radiate interior temperatures, whether cool or hot, back into the home. This means your house stays cool in the summer, and there is no need to blast your heater in the winter months.
In summary, the benefits of Low-E glass windows are:
Low-E Coating Performance Indicators
There are four different measures that indicate the effectiveness of Low-E glass, according to Vitro Architectural Glass:
Types of Low-E Glass Coating
There are two variations of Low-E glass coating, known as passive Low-E and solar control Low-E:
Which Low-E glass coating type is best for my climate?
After covering the two types of Low-E coating, you’re likely wondering which is the right choice for your home. The most influential factor in making this decision is your local climate.
Let’s explore which coating is best for each climate:
Do my windows have Low-E glass coating?
It’s been over 35 years since this coating revolutionized the window industry, so there’s a chance that your home already has Low-E windows. To determine if this is the case, you can do the following:
If you’re starting to explore a window replacement, and the many options available to you, it’s important to recognize the important of the glass type you choose. Window class has a major impact on the energy efficiency on your entire home. While Low-E coated windows are often slightly more expensive, the potential energy savings that accompany them make the investment worthwhile.