understanding replacement windows & their energy-saving benefits

Understanding Replacement Windows & Their Energy-Saving Benefits


As a homeowner, one of the most important things you need to think about regularly is the amount of energy your household consumes. In fact, you receive a monthly reminder of this figure in the form of your electric bill.

If you’re particularly energy-conscious, you probably already own or are thinking of switching to ENERGY STAR-rated appliances and know a lot of energy-saving tips and tricks. But did you know that one of the best ways to keep your consumption low is by installing high-performance replacement windows?

What Makes a Window Energy Efficient?

1



HOW INEFFICIENT WINDOWS WASTE ENERGY

According to the US Energy Administration’s 2010 Residential Energy Consumption Survey, the results of which were released in 2012, Americans use 47.7% of their total energy consumption to heat and cool their homes. And of this fraction, between 48% and 87% is wasted through inefficient windows.

ENERGY CONSUMPTION IN US HOMES BY END USES

34.6%41.5%

17.7%6.2%

appliances, electronics, etc. air conditioning

space heating water heating

THAT’S A LOT OF ENERGY AND MONEY OUT YOUR WINDOW!



HOW DOES YOUR HOME LOSE HEAT?

HOW DOES YOUR HOME LET HEAT IN?

floor walls roof windows

48%

18%

20%14%

87%

5%

8%



HOW HIGH-PERFORMANCE WINDOWS SAVE ENERGYEnergy-efficient windows help lower your total energy consumption in three ways:

■ by controlling how much HEAT passes in and out of your home,

■ by controlling how much SUNLIGHT enters your home, and

■ by controlling how much AIR leaks in and out of your home.

They accomplish this through the combined action of high-performance glazing, low-conductivity frames, viscous gas fills and warm-edge spacers. Window manufacturers use various combinations of energy-saving components to enable their products to achieve the desired performance ratings.

Speaking of which, the performance ratings used by organizations like the National Fenestration Rating Council (NFRC), ENERGY STAR and the US Department of Energy are all based on how well they control heat, sunlight and air.

WINDOW PERFORMANCE RATINGS

■ U-factor – a measure of a window’s insulating capacity or resistance to heat flow

■ Solar Heat Gain Coefficient (SHGC) – a measure of the amount of solar radiation transmitted through a window

■ Visible Transmittance (VT) – a measure of the amount of visible light transmitted through a window

■ Air Leakage (AL) – a measure of the amount of air that passes through each square foot of window area; an optional performance rating

■ Condensation Resistance (CR) – a measure of a window’s resistance to condensation formation between panes; an optional performance rating


In Part One of this e-book, we established how windows help make homes more energy efficient. They play key roles in daylighting and passive ventilation, both of which are core principles in green building. They also reduce unwanted winter heat loss and summer heat gain, helping your home stay energy-efficient all year round.

In this section, we’ll delve deeper into the different benefits that come with having energy-efficient replacement windows installed your home, starting with most homeowners’ favorite: lower energy bills.

Key Benefits of Energy-Efficient Windows

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MONEY SAVINGSThe long-term savings associated with energy-efficient windows is perhaps the biggest draw for the average American homeowner. According to ENERGY STAR, replacing single-pane windows with high-performance units can help the typical household save between $101 and $538 a year. Replacing double-pane clear glass windows, on the other hand, will result in savings of $27 to $153 a year.

Experts estimate that it’s possible for replacement windows to pay for their own price premiums within one to six years through energy savings alone. Real-world results will, however, depend a lot on local utility rates, climate conditions and individual home characteristics.

REDUCED CARBON FOOTPRINTThis is the obvious offshoot of consuming less energy to heat or cool your home. ENERGY STAR estimates that the amount of CO2 saved when replacing double-pane clear glass windows with high-performance windows is equivalent to the amount of CO2 produced when burning 13 to 95 gallons of gasoline. This zooms up to between 51 and 310 gallons of gasoline when you’re replacing old single-pane windows!



1,006 to 6,072

pounds of CO2

246 to 1,868 pounds of CO2

51 to 310gallons of gasoline

13 to 95gallons of gasoline

which is equivalent to

which is equivalent to

REPLACING SINGLE-PANE WINDOWS SAVES:

REPLACING DOUBLE-PANE CLEAR GLASS WINDOWS SAVES:



ADDED COMFORTYou won’t just feel the changes in your monthly utility bills; you’ll also feel it manifest as extra comfort inside your home. Old windows let in cold drafts in winter and too much heat in summer, two things that energy-efficient windows will quickly put an end to.

PEACE AND QUIETHigh-performance windows keep more than just unwanted heat out of your home; they also muffle noisy neighbors, the sound of traffic and other external distractions that are best left outside.

REDUCED CONDENSATIONEnergy-efficient windows see little to no condensation formation between their panes because of their ability to control temperature variations across the glazing. Less condensation means less moisture damage and a longer service life for your windows.

BETTER UV PROTECTIONMany energy-efficient windows have special low-emissivity coatings that act like sunscreen for your interiors. These protect your carpets, curtains and furniture from premature fading and damage.


Window performance requirements vary widely from one location to the next as not all areas will have the exact same heating and cooling needs.

Take the case of Pennsylvania. Homes in this state depend more heavily on heating than on cooling to keep living spaces comfortable. According to EIA, the typical PA household consumes 857 kWh per month—less than the national average of 909 kWh, but significantly greater than neighboring New York (607 kWh) and New Jersey (687 kWh). PA residents spend, on average, $109.66 a month for electricity.

The Pennsylvania Scene

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The Pennsylvania Scene

While a hundred bucks a month doesn’t sound too bad, DOE also estimates that the typical PA household can save $401 a year after replacing single-pane windows with ENERGY STAR-rated products or $166 after replacing double-pane windows. That cuts anywhere from one to four months’ worth of pre-replacement energy bills off of each household’s expenses, and that’s before you factor in rebates and incentives from local utility companies!

CHOOSING WINDOWS FOR PA HOMESEnergy performance ratings are among the most important factors to take into account when choosing replacement windows. Pennsylvania is split into Northern (heating-dominated) and North-Central (mixed) climate zones. Below are the performance ratings best suited for each climate zone:

■ U-factor• Northern: U ≤ 0.30 (superior energy performance

at U ≤ 0.25)• North/Central: U ≤ 0.32 (superior energy

performance at U ≤ 0.25) ■ Solar Heat Gain Coefficient• Northern: 0.35 ≤ SHGC ≤ 0.60 if A/C use isn’t an

issue, SHGC ≤ 0.35 if it is• North/Central: SHGC ≤ 0.35 if A/C use isn’t an

issue, SHGC ≤ 0.25 if it is ■ Air Leakage• Northern: AL ≤ 0.30• North/Central: AL ≤ 0.30

It always helps to check NFRC and ENERGY STAR labels when shopping for replacement windows, but it is equally important to recognize that no “one size fits all” solution exists. Even two identical homes located right next to each other may require different types of windows to achieve maximum energy efficiency.

For best results, consult a licensed local window replacement contractor you can trust.


RENEWAL BY ANDERSEN OF GREATER PHILADELPHIA761 5th Ave #3 King of Prussia, PA 19406

610-563-2190www.ChooseBetterWindows.com

http://www.ChooseBetterWindows.com

understanding replacement windows & their energy-saving benefits

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