What Makes a Window Energy-Efficient?

Tinted,glass,in,the,house.,window,dimming,by,dark,film.What Makes a Window Energy-Efficient?

As homeowners and building owners become increasingly aware of the importance of energy-efficient building practices and sustainability, they are searching for ways to improve the energy efficiency of their properties. One of the most significant ways to cut down on energy use and costs is by investing in energy-efficient windows. But what exactly makes a window energy-efficient, and how can you determine which windows are right for your home or building?

Here are some of the key factors to consider when deciding on energy-efficient windows from your local glass company.


Windows are available in a variety of materials, including wood, vinyl, fiberglass, and aluminum. Each material has its own set of pros and cons when it comes to energy efficiency.

Wooden windows have natural insulation properties and are a good choice for colder climates. However, they require more maintenance than other materials and are prone to warping and rotting.

Vinyl frames offer good insulation and energy efficiency and require less maintenance than wood frames. They are also relatively low cost and easy to install.

Fiberglass windows offer similar insulation properties to vinyl but boast a longer lifespan and are stronger and more durable.

Aluminum frames are not as efficient as other materials since they are poor insulators. However, they can be a good choice for mild climates or in conjunction with thermal breaks that improve their insulating abilities.


The type of home glass used in a window plays a significant role in its overall energy efficiency. Double-paned or triple-paned glass is an excellent way to improve insulation and reduce heat transfer, and it is typically filled with a gas, such as argon or krypton, which slows down the transfer of heat.

Low-E glass (low-emissivity glass) also helps to reduce heat loss. It has a thin, transparent coating on the glass that reflects heat and blocks UV rays, making it ideal for homes in hot climates. However, Low-E coatings may reduce the amount of natural light entering the home.

Air Leakage

Air leakage occurs when air infiltrates through the window frame and into the home. The more airtight a window is, the less heat energy it will lose. An energy-efficient window should have low air leakage rates, which is usually measured in cubic feet per minute (CFM) per square foot of window. Look for windows labeled with a lower CFM/sqft rating.


A window’s U-value measures the amount of heat transfer through the window. The lower the U-value, the better the window’s insulation properties. U-values range from 0.20 to 1.20, with lower values indicating better insulation.

Solar Heat Gain Coefficient (SHGC)

The SHGC measures the ability of a window to block heat from the sun. A lower SHGC means that the window is better at blocking heat, while a higher SHGC means that more heat is allowed to pass through the window. This value is especially important for homeowners in hot, sunny climates, where too much sun can lead to excess cooling costs.


Proper window installation is critical to achieving maximum energy efficiency, regardless of the quality of the window material itself. Even the best energy-efficient window that is improperly installed can lead to air leaks and wasted energy.

To ensure proper installation, it’s best to hire experienced professionals with residential and multi-family unit glass who understand the specific requirements of energy-efficient windows. In addition to proper installation, high-quality window seals, caulk, and insulation materials should also be used to eliminate air leaks and enhance the window’s energy efficiency.


Investing in energy-efficient windows is a great way to reduce your home or building’s energy consumption and costs while promoting sustainability. When selecting windows, look for materials, glass, and other components that promote energy efficiency and reduce heat loss, such as Low-E coatings, multiple panes, and low U-Factors and SHGCs. Proper installation of the windows is also essential to achieve the maximum energy efficiency benefits. By taking these factors into account, homeowners and building owners can make smart decisions regarding the selection and installation of energy-efficient windows, which can lead to long-term energy savings and decreased environmental impact. Contact us today to get started!