May 04 , 2023

How Do You Understand Energy Star Labels & Specifications


The ENERGY STAR label is widely recognized as the official mark of energy efficiency. Consumers and businesses alike rely on this easily identifiable blue label to make informed decisions that are based on reliable and unbiased information. But how do you understand ENERGY STAR Labels & Specifications?
Energy Star-certified window labels must include at least four performance value ratings: ER, VT, U-factor, and SHGC. However, only the U-factor and Solar Heat Gain Coefficient are required for door labels. Manufacturers can include ratings for condensation resistance (CR), air leakage (AL), and information on CSA certification.
In this article, we will take a look at the energy star labels and specifications so you can make a sound decision while buying windows.


Why Prefer Energy Star Certified Windows and Doors?

Choosing ENERGY STAR-certified windows and doors can help you in several ways. Firstly, you can save money on your energy bills as these windows and doors consume less energy.
Secondly, they help maintain a comfortable temperature inside your house throughout the year. Lastly, during colder months, you may also experience less condensation with these windows and doors.

Energy Star Labels & Specifications

To receive an ENERGY STAR label, windows must meet certain energy efficiency specifications. These specifications are based on different factors. The ENERGY STAR Labels & Specifications are:


Understanding the U-factor or U-value is crucial when selecting energy-efficient windows. This rating indicates the amount of heat transferred or lost through a window. The lower the U-value, the better the window insulates, resulting in reduced energy costs.

Be cautious when comparing U-values across manufacturers, and ensure you are looking at the complete window rather than just the glass. A 0.22 U-value is 35% more efficient than a 0.30 U-value.


The solar heat gain coefficient (SHGC) measures the amount of solar energy that passes through the window and into your living space. By selecting windows with the appropriate SHGC levels, you can effectively manage temperatures in different areas of your home and enhance your interior comfort, especially if you live in areas with extreme seasonal temperatures.

In the summer, rooms that receive direct sunlight throughout the day can become uncomfortably warm, but by choosing windows with a lower SHGC, you can reduce the amount of heat that enters your home. Conversely, in the winter, windows with a higher SHGC can help increase the amount of solar energy that enters your home, providing natural warmth and reducing your heating bill.


The Energy Rating (ER) measures the energy efficiency of windows. The higher the ER value, the more efficient the window is.

This measurement takes into account a window's air leakage, solar heat gain coefficient (SHGC), and U-factor to provide an overall performance rating. The ER value accurately represents the window's overall performance by evaluating these factors.


The VT rating measures the amount of light that can pass through a glass unit. The higher the number, the more light can enter your space.

However, factors such as glazing, coatings, tints, and gas fills can reduce the amount of light entering your space. This is where insulated glass units (IGUs) come in. An IGU is a type of glass unit with a VT rating, quantifying the amount of light it allows to pass through.

Energy Star Window Label Requirement

The ENERGY STAR window label can help you find a suitable energy-efficient window. Here are the Energy STAR window label specifications you should consider:

● The certification mark of ENERGY STAR

● "Do Not Remove" warning

● Performance values (ER, VT, U-factor, SHGC)

● Name of the manufacturer

● Type of model frame

● Type of model operator

● Glazing description includes:

1. The number of layers of glazing

2. The total number of filled cavities, gas fills

3. The surface number(s) and Low-E coating as applied

4. An interior grill's generic height (if applicable)

● Nrcan number or model code

● The certification test standard for the model

● Text of the testing and warranty disclaimer

Air Leakage (AL)

Air Leakage (AL) is an essential factor in determining the energy efficiency of windows. The AL rating measures the amount of air that penetrates through the cracks in the window assembly, resulting in heat loss or gain. The lower the AL value, the less air penetration occurs.

It indicates the amount of equivalent cubic feet of air that leaks through one square foot of window space. The AL rating must be 0.30 or below to qualify for ENERGY STAR Certification. The smaller the AL value, the better the window prevents air leakage and improves energy efficiency.

Condensation Resistance (CR)

Condensation Resistance (CR) measures the likelihood of condensation forming on the inside of a window.

The higher the CR number, the better the resistance to condensation. Although it is not mandatory for ENERGY STAR certification, it is an important feature. This is because it can prevent moisture damage and improve indoor air quality.


The R-value is a measure of the thermal resistance of a material, indicating its insulating capabilities. A higher R-value signifies more efficient insulation. While not mandatory for the ENERGY STAR requirement, some window salespeople may use the R-value to evaluate and compare insulation capacity.

It is a valuable tool when comparing different window designs and insulated spaces, providing a standardized unit of measurement for thermal resistance to heat transfer by conduction.

Make Your Right Choice

Energy efficiency should be your primary priority when selecting the correct windows for your house. Before making a purchase, consider the impact each window will have on the comfort of your house or each room. Keep in mind that every home is unique and may have room-to-room issues depending on its orientation to the sun.

If you notice any excessively warm or chilly rooms, be sure to mention them to your window consultant. They'll work together with you to find the ideal balance between comfort and energy efficiency.


After reading this article, we hope you now understand the ENERGY STAR labels and specifications. When shopping for energy-efficient windows, the ENERGY STAR label is an important certification to look for.

ENERGY STAR certified windows are designed to meet strict energy efficiency specifications. By choosing these windows, you can save money on your energy bills and improve your home's comfort.

How Do You Understand Energy Star Labels & Specifications

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