Energy Ratings for Windows and Doors

Understanding energy ratings for windows and doors is important when it's time to replace them.  Just because the windows and doors have the Energy Star label doesn't mean they are eligible for the federal tax credit.  Energy efficient windows range from $500 to $1,000 per window on average.  Therefore, it's a wise investment of your time to know you will get the tax credit you deserve.  And, energy efficient windows and doors help add value to your home, making it more appealing to buyers.

Labels That Matter

There are two labels you should look for when replacing your windows with energy efficient ones.  One is the U.S. Department of Energy's blue and yellow Energy Star label and the second is the white National Fenestration Rating Council label.  

Requirements for the Tax Credit

As of June 1, 2009, you have to qualify for the tax credit on windows and doors to receive it.  Two NFRC supplied measurements have to be equal to or less than 0.3.  You will also need the manufacturer's signed statement that the product complies with IRS requirements.  You can get this statement when purchasing the windows and doors or you can download it from the manufacturer's website.

A Measurements Guide

There are five measurements typically listed on the NFRC label, including the tax credit U-factor and SHGC.  Here is a list of those measurements: 

1.    U-Factor - Range 0.20 to 1.20.  The lower the number, the better insulated the window or door is.  The tax credit qualification is 0.3.  Recommendations for Northern climates is 0.35 or less, North Central and South Central climates is 0.4 or less, and Southern climates is 0.60 or less.

2.    Solar heat gain coefficient - Range 0 - 1.  The lower numbers mean less solar radiation and heat that will enter the windows and doors.  The tax credit qualification is 0.3 or less.  Recommendations for Northern climates is up to 0.55, North Central climates is 0.4 or less, South Central and Southern climates is also 0.4 or less.

3.    Visible transmittance - Range 0 to 1.  The lower numbers mean the room will be slightly dimmer.  A high number will mean the room will be brighter.  There is no tax qualification and these numbers apply to windows and doors only.

4.    Air leakage - The range is not available, but 0.3 is the standard building code.  The lower number means the more airtight the window or door will be.  There is no tax qualification.

5.    Condensation resistance - Range 1 - 100.  The lower number means the more condensation the window or door will allow for buildup.  There is no tax qualification.

Learning the language will be well worth your time.  Window replacements are an excellent remodeling project when you look at the terms of investment.  You can easily recoup around 78% of the project cost.  That's between $10,500 and $13,600 over their lifetime.