When you look for replacement windows, you need to check the materials, cost, design, and color. However, most people ignore the bunch of numbers at the back. Pay close attention to those numbers, however, as they tell you how energy-efficient your windows are.
There are actually two labels: the blue and yellow one from the Department of Energy and the white one from the National Fenestration Rating Council (NFRC). In this article, we will focus on the energy performance label by the NFRC.
The NFRC Ratings
The NFRC is a non-profit organization, industry-recognized certifying body for doors and windows. This organization performs the tests on home building products in terms of energy efficiency. Note that the test is performed on the entire product, not just on the glass or frame.
The NFRC label typically indicates five measurable properties:
This is the rate at which the window conducts non-solar heat flow. Usually expressed in the units of Btu/hr-ft2-oF, U Factor may refer to the glass or glazing only. Measurement ranges from 0.20-1.20. The lower the number, the better the product in regulating thermal transfer.
Solar Heat Gain Coefficient (SHGC)
Look for the SHGC if you want to know how well your picture windows can resist unwanted heat gain. It ranges from 0 to 1 and your choice will be based on where you live. The lower the SHGC, the less solar heat it will transmit.
Visible Transmittance (VT)
This measures how effective your window is in letting in natural light. Just like SGHC, the range is from 0 and 1. Look for higher numbers on your replacement window if you want to save on artificial lighting costs.
This indicates how much air will enter the room through your window and ranges from 0.1 to 0.3. To experience fewer drafts, look for low numbers in this category.
Condensation varies in severity, depending on how effective your window can resist it. Condensation resistance ranges from 1-100 and homeowners are advised to look for high numbers.
Now that you know the basics of these ratings, it is time to think about their importance. First, these numbers are required not only when it comes to saving energy costs, but also when filing for tax credit. In order to qualify, your sliding windows should have equal or less than 0.30 U-Factor and SHGC. You also need to submit the manufacturer’s signed statement that the product complies with IRS requirements.
Second, ratings will remind you if you are an environmentally responsible homeowner in terms of energy usage. Besides, it is our duty to help save the environment by using products that do not produce too many chemicals and won’t contribute to climate change.
For more information on energy performance ratings or for free estimates of our windows, call us today at (505) 273-2815. We serve residents of Albuquerque, NM, and the surrounding areas in New Mexico.