Understanding Energy Efficient Windows & Doors' Rating and Terms

Understanding Energy Efficient Windows & Doors' Rating and Terms

Energy efficient windows and doors are becoming increasingly popular. These products can save you money by reducing your energy bills and increasing the value of your home. They also offer excellent insulation properties, which help to reduce the amount of heat or cold in your home.

There are many factors that affect how much a window or door will cost you to install. The type of material used, the size of the window and door, and what type of insulation it has will all have an impact on the final price tag. Understanding these costs can help you decide whether or not an Energy Efficient Windows & Doors product is right for your home.

What is the U-Value/Factor of a window?

The U-value or U-factor of a window is a measure of how much heat can transfer through the window from inside to outside or vice versa. Specifically, it is the rate at which heat flows through one square meter of a window when the temperature difference between the inside and outside is one degree Celsius. The lower the U-value, the better the window's insulation properties and the more energy-efficient it is.

When purchasing windows, here are some factors to consider to choose ones with better energy efficiency:

What is the solar heat gain coefficient?

When it comes to choosing windows for your home or business, there are many factors to consider, including energy efficiency. One key metric to look at is the solar heat gain coefficient (SHGC). This measures how well a window can block heat gain from the sun, which is an important consideration for climates with hot summers.

The SHGC is expressed as a number between 0 and 1, with lower numbers indicating better performance. A window with a lower SHGC will block more solar heat and help keep your home cooler in the summer. Conversely, a window with a higher SHGC will allow more solar heat to enter, which can lead to increased cooling costs.

What is the design pressure?

When it comes to choosing windows for your home or business, it's important to consider factors like energy efficiency, style, and durability. One key metric that you should be aware of is the design pressure (DP) rating. This measures the ability of a window to withstand high wind loads and other environmental stresses.

The DP rating is expressed as a number, with higher numbers indicating better performance. A window with a high DP rating is more likely to withstand strong winds, heavy rain, and other weather-related stressors. This means that it will last longer and require fewer repairs over its lifetime.

All windows have an ENERGY STAR rating, but not all windows will be energy efficient, you need to learn to read labels.

When it comes to improving your home’s energy efficiency, one important upgrade to consider is your windows. Not all windows are created equal when it comes to energy efficiency, so it's important to know how to read labels and select windows that will help you save money on energy costs while also reducing your carbon footprint. In this blog post, we'll cover some key factors to consider when purchasing energy-efficient windows.

Understanding the ENERGY STAR Rating

The ENERGY STAR program is a joint initiative between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy (DOE) that sets energy efficiency standards for various products, including windows. All ENERGY STAR certified windows meet minimum performance requirements for energy efficiency, but not all windows with an ENERGY STAR rating are created equal.

ENERGY STAR ratings for windows are based on two main factors: U-factor and Solar Heat Gain Coefficient (SHGC). The U-factor measures the rate at which heat is transferred through the window, while the SHGC measures how much solar heat is allowed to pass through the glass. Lower U-factors and SHGCs indicate better energy efficiency.

Understanding Labels

When shopping for energy-efficient windows, knowing how to read labels is important. Look for labels that provide information on the U-factor and SHGC of the window, as well as the manufacturer's name, product name, and any applicable certifications or ratings.

Additionally, look for labels that provide information on the window's air leakage, which measures the amount of air that can pass through gaps in the window. Lower air leakage ratings indicate better energy efficiency.

Choosing the Right Frame Material

The frame material of your windows can also impact energy efficiency. The most common materials for window frames are vinyl, wood, fiberglass, and aluminum. Vinyl and fiberglass frames are typically the most energy-efficient, as they are better insulators than wood or aluminum. However, wood and aluminum frames may be preferred for their aesthetic appeal or durability.

Choosing the Right Glass

The type of glass used in your windows can also impact energy efficiency. Double-pane windows are more energy-efficient than single-pane windows, as they provide an additional layer of insulation. Additionally, some top window and door manufacturers offer triple-pane windows for even better insulation.

Low-E glass is another option for improving energy efficiency. Low-E glass has a special coating that reflects heat back into the room during the winter months, while allowing sunlight to pass through during the summer months. This helps regulate your home’s temperature and can save you money on heating and cooling costs.


Purchasing energy-efficient windows can be a smart investment for your home, but it's important to know how to read labels and understand the factors that impact energy efficiency. When shopping for windows, look for ENERGY STAR certified products