How ENERGY STAR® Certified Windows Can Save You Money

ENERGY STAR certified windows can save you an average of 12% on your energy bills every year, along with other energy efficient features depending on the window manufacturer. Old, inefficient windows can let in a lot of hot and cold air, which can drive up your energy costs. But there’s good news: ENERGY STAR certified windows can help you save money and improve the comfort of your home.

ENERGY STAR certified windows are:

  • Independently tested, certified, and verified by the National Fenestration Rating Council (NFRC).
  • Independently certified to meet strict energy efficiency guidelines set by the U.S. Environmental Protection Agency (EPA).
  • Manufactured by an ENERGY STAR partner.

NFRC Energy Efficiency Ratings 

An infographic labeling energy efficiency ratings.

  • Thermal Transfer: A window’s thermal transfer, known as its U-factor rating, is its most important rating. It is the rating that organizations such as Energy Star use to qualify windows as “Energy Efficient” windows. The U factor measures the energy efficiency of the entire window. 

What to look for: Low Numbers 

  • Radiant Heat: The Solar Heat Gain Coefficient measures radiant heat that can pass through a window. Radiant heat is most easily noticed by the hot spots that one feels when he touches the floor where the sun has been shining. In northern states a higher SHGC is better because it lets in more radiant heat. In southern states, where keeping a house cool is more important, a lower SHGC is better.

What to look for: High Numbers in the North, Low Numbers in the South

  • Tightness: Air leakage ratings are represented by the tightness of your window, measuring how much air escapes. Air escaping through windows and doors can account for up to 35% of heating/cooling loss.

A white window frame set against the brick exterior of a home.

What to look for: Low Numbers

  • Tinting: The tint in your window, known as the Visible-Transmittance, is simply the amount of visible light that a window allows into the room. The higher the VT, the more light passes through the window.

A close-up of a home's tinted window.

What to look for: High Numbers

  • Moisture: Condensation Resistance, seen as moisture or lack of moisture, measures how well a window resists the formation of condensation on the inside surface. CR is expressed as a number between 1 and 100. 

What to look for: High Numbers 

About the NFRC 

The National Fenestration Rating Council (NFRC) rates the energy performance of windows, doors, and skylights. These ratings can be a valuable comparison tool because they help you to:  

  • Compare different products on an apples-to-apples basis.
  • Make sure that a product will perform as it should by verifying information
  • Make an informed choice about a substantial investment that will stay in your home for many years.

Energy Star performance Ratings Graphic

The NFRC Label: The NFRC label, such as this one, provides homeowners with the key performance metrics on any window. Want the easiest way to compare window performance? Ask to see the window’s NFRC sticker!


  • Wind Load Resistance: The Design Pressure Rating represents the maximum positive and negative wind load that a window or door can experience without breaking, deglazing or permanently distorting. This rating is put in place by the North American Fenestration Standard (NAFS).

What to look for: High Numbers 

  • Forced Entry/ Air & Water Resistance: A product achieves a performance grade rating, measuring forced entry/air & water resistance, if that product complies with all requirements of the NAFS for a certain design pressure (wind load) corresponding to a maximum expected impact at a given location. Performance grade measures: 
    • Structural performance  
    • Water penetration resistance  
    • Air infiltration resistance 
    • Uniform load-deflection test 
    • Forced-entry resistance (if applicable) 

Features in Windows That HELP Save Energy 

Using the window ratings we have identified, the following features make up a window’s ability to save energy.  

  • Type of frame: Depending on the type of frame, one material will provide more insulation over the other. 
    • Vinyl: Great thermal performance when installed correctly and filled with insulation.
    • Wood: Lower thermal performance than its counterparts.
    • Aluminum: Poor insulation, conducts heat quickly.
    • Fiberglass: Great insulators compared to wood and aluminum.
  • Glass Panes: More than one glass pane helps to resist heat transfer and improve insulation in your home.

White-framed windows on the side of a small home.

  • Low E Glass Coating: Low e coating allows for optimal natural light and minimal heat/UV rays. The process is selective of the solar spectrum it lets in.
  • Warm Edge Spacer: Maximizes energy efficiency and improves seal performance of insulated glass units. 
  • Weatherstripping: Weatherstripping, also known as a window gasket or window seal, is an insert in your windows to prevent outside temperatures from seeping into your home. This keeps the inside of your home cool in the summer and warm in the winter, which is how it should be. 

Infographic of the inside of a window.

  • Gas Fill: Argon gas is often used in multiple pane windows. This insulates the window and provides optimal comfort in your home. 
  • Proper Installation: Without proper window installation from a certified team, your windows could be subject to extra costs. Improper measuring or overall fit allows air in and heating or cooling out.  

A west shore home employee measuring a window sill before a window install.

Choosing ENERGY Star CERTIFIED Windows

ENERGY STAR certified windows are a great way to save energy and money on your home’s heating and cooling bills. They are made with energy-efficient materials and features that help to keep your home comfortable all year round. When choosing new windows, be sure to look for windows with low U-factors, high SHGCs, and tight air seals. You should also consider the type of frame, Low e glass, number of glass panes, and other features that are important to you. With ENERGY STAR certified windows, you can enjoy a more comfortable and energy-efficient home.

West Shore Home® offers a free, expert consultation to help you choose the perfect energy-efficient replacement windows for your home. Our trained, full-time remodelers will work with you to personalize your window installation and ensure that it meets your needs and budget. From expansive bay windows to compact awnings, all of our replacement windows save energy thanks to features like ENERGY STAR.

Here are some of the benefits of choosing West Shore Home for your replacement windows:

  • Free, expert consultation
  • Personalized window installation
  • Energy-efficient windows that save you money on your energy bills
  • A team of trained, full-time remodelers
  • A satisfaction guarantee

To get started, simply contact West Shore Home today. We’ll be happy to answer any questions you have and schedule a consultation at your convenience!