• Roofing
  • Siding
  • Windows
  • Audits
  • Upgrades

Measuring energy savings in your Michigan replacement windows

energy saving

You have heard again and again that installing new, energy-efficient windows in your home will help reduce energy use and cut your monthly heating and cooling bills. How much? The U.S. Department of Energy has determined that at least 30% of a home’s energy can be lost through inefficient windows. That’s like throwing nearly one-third of the money you spend to heat and cool your home out the window!

Aaron’s Home Improvement is a Michigan replacement windows contractor that can offer you windows that are among the most efficient on the market, with superior thermal performance that is built into the frames, glass and entire window package.

You can measure the difference! National window industry standards have been established for rating the energy performance of replacement windows. Here is what you should look for in replacement windows Michigan:


The most important measure of a window’s performance is its U-value. The U-value indicates the rate of heat flow through a window. The lower the U-value, the more energy efficient the window will be. U-value measures the entire window unit — glass, frame, sash, spacers — and is the only measurement accepted by the U.S. Department of Energy’s EnergyStar program.


R-value is the measure of the resistance of glass to the flow of heat. The higher the R-value, the better the glass will be at insulating your home. But R-value is NOT an accepted form of measurement by the National Fenestration Research Council (NFRC) or EnergyStar, as it does not measure the overall window unit.

Solar Heat Gain Coefficient

Solar Heat Gain Coefficient (SHGC) measures how well a product blocks heat caused by sunlight. The SHGC is the fraction of incident solar radiation admitted through a window and absorbed and subsequently released inward. SHGC is expressed as a number between 0 and 1. The lower a window’s solar heat gain coefficient, the less solar heat it transmits.

Visible Transmittance

Visible Transmittance  (VT) measures how much light comes through a product. The visible transmittance is an optical property that indicates the amount of visible light transmitted. VT is expressed as a number between 0 and 1.  The higher the VT, the more light is transmitted.

Air Leakage*

Air Leakage (AL) is indicated by an air leakage rating expressed as the equivalent cubic feet of air passing through a square foot of window area (cfm/sq ft). Heat loss and gain occur by infiltration through cracks in the window assembly. The lower the AL, the less air will pass through cracks in the window assembly.

Condensation Resistance*

Condensation Resistance (CR) measures the ability of a product to resist the formation of condensation on the interior surface of that product. The higher the CR rating, the better that product is at resisting condensation formation. While this rating cannot predict condensation, it can provide a credible method of comparing the potential of various products for condensation formation. CR is expressed as a number between 0 and 100.

*This rating is optional and manufacturers can choose not to include it.

What is the NFRC?

The National Fenestration Research Council (NFRC) is an independent, non-profit organization that administers the only nationally accepted rating system for energy performance of windows, doors and skylights. The NFRC provides fair, accurate and reliable energy performance ratings so that architects, engineers, builders, code officials, contractors and homeowners can compare different products and make informed choices. Look for the NFRC label on any window you purchase.

Request a FREE Window Estimate

Ready to make your home more beautiful and energy efficient? Call the replacement window Michigan experts at 888-442-2766 today to schedule a FREE in-home window consultation and estimate.