All About Green Living Gazette

What Should I Look For When Buying Energy Efficient Windows?

Jul 10

There are many factors to consider when looking for energy-efficient windows. Among these are the low U-factor and solar heat gain coefficient, the presence of two panes of glass, and any warranties.

Each of these factors has its benefits and drawbacks. By learning more about these factors, you can make a more informed decision when it comes to choosing energy-efficient windows.

Before you start shopping around and calling quality window replacement contractors, consider a few tips to make the process of buying them as smooth as possible.

Low U-factor

When buying energy-efficient windows, you should look for the U-factor. The U-factor is a measurement of the rate of heat transfer through the glass or glazing. The lower the U-factor, the better the energy-efficiency of the window.

NFRC ratings for windows reflect the entire window's performance. A lower U-factor will save you the most energy in a cold climate. NFRC labels also indicate air leakage and visible transmittance.

There are two primary ways to measure window performance. First, the U-factor shows how well a product insulates a room. A low U-factor is important for cold rooms because it prevents heat from passing through the window.

Low-U-factor windows are beneficial for all orientations, and a U-factor below 1.4 W/m2K is recommended for frigid winter climates. In addition, the Energy Rating also reflects the solar gain effect of the window.

Low solar heat gain coefficient

One metric to look for when buying energy efficient windows is the low solar heat gain coefficient (SHGC). This number is a measurement of the amount of solar radiation that passes through a window. A lower SHGC means less solar heat will enter your home, lowering your cooling costs during summertime.

On the other hand, a high SHGC means that solar heat will collect in your home during wintertime, lowering your heating costs. 

Climate factors

Another factor to consider when choosing energy efficient windows is climate. There is no single type of window that suits every climate, and one type will not work for everyone.

In temperate climates, low SHGC will maximize energy savings and reduce the use of air-conditioning equipment. To ensure optimal energy efficiency, look for windows with a low solar heat gain coefficient and low U-factor. You can also look for low-e coatings on the glass.

Visual transmittance

In addition to low solar heat gain coefficient, consider visible transmittance (VT) as a measure of light transmission. It indicates the level of sunlight that comes through a window.

In the past, VT was equal to the solar heat gain coefficient. Today, however, low-e coatings can reduce solar heat gain and maintain room comfort. The ratio between SHGC and VT measures the amount of light a window can transmit while still reducing solar heat gain.

Two panes of glass

When buying energy efficient windows, look for two-pane windows. Double-pane windows contain two layers of glass, which are separated by a spacer (usually gas). The spacer prevents heat transfer, which can help you save money on your utility bills. 

To find energy-efficient windows, check out the U-value. Double-pane windows with low U-values can save you between $101 and $5381 annually. The extra insulation helps regulate the internal climate of your home, putting less strain on your air systems. Although double-pane windows are beneficial for colder climates, it's important to remember that they may not be necessary in warm regions.

Most newer windows have two or three panes of glass. Although more panes doesn't necessarily mean better, a local window dealer can help you determine what number of panes is best for your climate. 


There are some things to keep in mind when looking for warranties on energy-efficient windows. Some warranties cover only new construction while others cover installation and replacement parts.

Read the fine print carefully to determine if your windows are covered. 

Some manufacturers offer lifetime guarantees on their products, while others offer warranties that last for as long as 30 years. Look for a warranty that covers all the parts and labor, including glass seals. You should be able to transfer the warranty if the window does get damaged. This is a great way to ensure the durability of your windows, and also make sure you have peace of mind.

Also, be sure to look for a good window installation company with a good reputation and a long list of satisfied customers.


When you install energy-efficient windows in your home, you'll be saving money each month by not using as much heating and cooling equipment. Additionally, these windows are more durable than traditional windows.

Durability and energy conservation are both key factors in life-cycle cost. There are many different types and styles of energy-efficient windows, from insulated to non-insulated. You can also pick between wood and vinyl windows.

The more durable and resillient the window material, the laster it will long and remain energy efficient.


When purchasing energy-efficient windows, be sure to choose windows with the proper frame material. Window frames can be made of vinyl, wood, aluminum, fiberglass, or a combination of materials. Each of these materials has different strengths and weaknesses.

Wood windows are easy to maintain but require frequent maintenance. Fiberglass windows are low-maintenance and stable. Finally, aluminum windows are poor energy-efficient and heat conductors.

All connections that hold the frame together must be tightly sealed. In addition, weatherstripping and top-quality hardware should be properly installed around the sash opening. The material should be durable, too.

To end

Choosing energy-efficient windows is easy, and can be done with a little research. When buying new windows, keep it simple by researching energy star rating.

Even if energy-efficient windows initially cost more than their counterparts, they can save you a lot of money on energy bills over the years.

Look for a reputable replacement window business that stands behind their work. This is important as  poor installation will cause the window to not function properly.