Understanding Energy Ratings for Windows Replacement

When you’re considering a Saratoga, CA windows replacement, energy ratings will be one of the factors that will guide your final decision. But most of us are not physicists, so we don’t readily understand what we’re looking at when we see the energy rating numbers on windows replacement labels.  

A windows replacement that is rated as energy-efficient will usually have two energy ratings labels. One is the Energy Star label, which indicates that the windows replacement has met the Environmental Protection Agency’s (EPA) precise criteria for energy efficiency. The second label you will see is white and is from the National Fenestration Rating Council (NFRC), a non-profit organization that provides industry-recognized certification for a windows and doors.   

Both the Energy Star labels and the NFRC label provide four measures for a windows replacement window:  

• U-Factor – The range of numbers goes from .20 to 1.20. This measures the insulation of the replacement window. The lower the number is, the better insulation the replacement window provides.  
• Solar Heat Gain Coefficient (SHGC) – The range of numbers goes from 0 to 1. This measures how much heat (solar radiation) the replacement window lets inside the house. A lower number correlates to less heat allowed in by the replacement window. 
• Visible Transmittance – The range of numbers goes from 0 to 1. This measures how much light the replacement window will allow to pass through. The higher the number, the more light the replacement window will allow to pass through. 
• Air Leakage – There is no range for this measurement, but the standard building code is 0.3. A lower number correlates to a more airtight replacement window. 

The NFRC label provides one additional measurement that the Energy Star label does not:  

• Condensation Resistance – The range of numbers goes from 0 t0 100. This measures how much moisture a replacement window will allow to build up on its surface or between glazing layers. This is a factor that needs to be considered because excess condensation on the replacement window surface can drip onto a wood window frame, causing mold and, over time, rotting the wood. Excess condensation between the glazing layers of a replacement window will create obstructions that will limit your visibility and which cannot be removed. The higher this number is, the less condensation the replacement window will allow to build up. 

Energy ratings for windows replacement are very important, especially when you are investing time and money into a significant remodel or upgrade project for your home. Not only are you trying to increase your home’s energy efficiency, but you also want to make sure that the benefits you get from your windows replacement will last for many years to come.  

If you are interested in knowing more about Saratoga, CA windows replacement, you can speak with one of our knowledgeable staff members at California Custom Creations. You can contact us at (408) 316-6293 to make an appointment for a free in-home consultation.