How Much Energy Are You Losing Through Your Old Windows?

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Are you losing heat and cold air through your old windows? This thermal image, taken by a professional energy auditor, shows how the warmest air (shown in red) escapes through the windows and doors.

are you losing heat

An average home loses up to 30% of its heating and cooling energy through air leaks around windows and doors. If you have leaky windows, you also have rising energy costs. If your windows are more than 10 years old, replacing them may put an end to your skyrocketing heating and cooling bills.

By upgrading your older windows to energy-efficient windows with low-E coatings, you can lower your energy bills up to 15 percent per year, according to the Efficient Windows Collaborative, a coalition of government agencies, research organizations, and manufacturers that promote efficient window technology. A recent study by Energy Star revealed that by switching out your single-pane or even your newer double-paned, clear-glass windows to energy-efficient windows, you can save up to $465 a year.


When you upgrade from old to energy-efficient windows, there is no doubt that you will save money on your utility bill, how much money really depends on the climate in which you live. Consider these factors when determining to choose an energy-efficient window:

  • The U-factor – the rate of heat loss for an entire window
  • The Solar Heat Gain Coefficient (SHGC) measures how effectively the window blocks heat coming from the sun. The lower a window’s solar heat gain coefficient, the less solar heat it transmits.
  • Energy Star rating:  In the South, humidity is tough on windows. At LAS, our rating exceeds the Southern U.S. requirements by 30%.
  • Low – E glass – This glass reflects 40% – 70% of the sun’s energy back where it came from so that means your home will stay cooler. Cardinal® LoĒ³-366 is a soft coat low e -glass that performs at a much higher level when it comes to blocking infrared light. LAS exclusively uses Cardinal® LoĒ³-366 Glass because it is ideal for southern climates dominated by air conditioning use.

Lower values represent increased insulating performance

U-Value Solar Heat Gain Coefficient
Clear Glass 1.04 .86
Ordinary Low E .30 .72
Cardinal® LoĒ³-366 .24 .27



If you choose a high-quality window and have a well-qualified, professional, experienced installer install your windows, you can expect from 25% to 52% savings on your energy bill.  For example, investing $10,000 in replacement windows will save you 40% of your annual $3000 bill or $1200 a year. And not only will your savings make up for the cost of your new windows, you will also experience a more comfortable home with enhanced beauty and value.

Window replacement is one of the best home remodeling projects in terms of investment return according to the “2015 Remodeling Impact Report” from the National Association of Realtors. For average-quality vinyl windows, you can recoup 80% of the project cost in added home value. That’s a value-add of $12,000 if you should decide to sell your house.


Call LAS today for your FREE estimate!

Posted in: Buyer's Guide Doors Energy Efficiency Home Improvement Windows

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