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Get The Facts On Energy Efficient Windows Part 1
Shopping for new windows can be easier if you’re armed with the same knowledge that the replacement window manufacturers have.

Wondering if you need replacement windows? According to the Window and Door Manufacturers’ Association (WDMA), new windows can be up to 45% more energy efficient. If you happen to have windows that are at least 20 years old, they produce 5.3 tons more greenhouse gases per year than new windows. And finally, windows account for 10-25% of your home’s total energy consumption, so upgrading to more energy efficient windows can start saving you money from the moment their installed.

No Shortcuts

Are new windows really necessary if the ones you have seem inefficient? Ask the experts if putting up sun blocking window shades or cheap window films will solve the problem and they’ll say No! Firstly, products that block the sun do not prevent drafts and air leaks, which continue to rob heat and make your home less comfortable. Second, films cannot be removed in the winter, when rooms can be naturally warmed by solar heat, losing this free heating alternative. They can also blur the view and discolor over time. Thirdly, covering windows with sun blocking shades increases the need to use artificial lighting, adding to your electrical consumption – and electric lights can also add more heat to the room. And of course, you’re sacrificing the view by covering up windows.

How Can You Be Sure a Window is Efficient?

Window professionals and the government have objective standards for ensuring the energy efficient properties of windows and doors. Take a moment to understanding these common terms. It will help you select the right products when it’s time for replacement doors and windows. 

U-factor is a measure of the rate of heat loss, indicating how well a window or door insulates. The lower the number, the better a window or door is at keeping heat inside a building. A favorable U-factor is important in the winter months to keep your home comfortable and utility bills lower. 

Solar Heat Gain Coefficient (SHGC) tells you how well windows and doors block heat from the sun – the lower the number, the better for your comfort and efficiency. In southern climates, such as greater Atlanta, or high sun intensity areas within a particular home, you might actually want to keep the sun’s heat out of your house. Windows with a relatively low SHGC can help you do that.

R-value is an indication of how well a window or door resists heat loss. You may know about R-value from shopping for home insulation products like the pink attic insulation. For windows and doors, U-factor and solar heat gain coefficient are more important measurements, and good window and door retailers will focus on those two measures, rather than R-value.

And finally, Design Pressure Rating (DP) gives you the amount of pressure a door or window will withstand when closed and locked. It can tell you how well a window or door will keep drafts and rain from blowing in during a windy storm, for example. DP rating also can tell you how well windows and doors can resist forced entry and how much force it could take to open or close the window or door. The higher the DP number, the better your can expect the product to perform. This rating is the certified hallmark of the Window and Door Manufacturers Association.



Windows and doors either do not meet, meet, or exceed the performance requirements for energy reduction set down by the U.S. Department of Energy and the U.S. Environmental Protection Agency in their ENERGY STAR ratings. Look for products that qualify for the ENERGY STAR rating in your climate region. Visit energystar.gov for more information and energy star rated windows and doors.


National Fenestration Rating Council is a not-for-profit group that sets standards for the window and door industry. As an example, Infinity replacement windows earned one of the highest possible ratings for energy performance from this organization. This rating measures light transmission and heat loss or heat gain in a variety of conditions.

With this knowledge under your belt, you can shop for replacement doors and windows and feel confident that they will add newfound comfort and energy efficiency to your home.

For Get the Facts on Energy Efficient Windows Part 2, click here.

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