In order to determine the best windows for your house, it’s important to analyze the Return on Investment (ROI) that a new window will bring.  While new windows can improve resale value and aesthetics, this ROI will also depend heavily on energy efficiency. Energy efficient windows take local environment and weather patterns into account, meaning an ‘energy-efficient window’ may not look the same across the nation.  The three aspects of a replacement window to consider are U-factor, solar heat gain coefficient (SHGC), and air infiltration.

ENERGY STAR^® Climate Map

ENERGY STAR created a climate map to help homeowners determine the ideal U-Factor and SHGC ratings for their windows based on climate. The map splits the country into four parts- Northern, Northern Central, Southern, and Southern Central.  In northern climates, it’s recommended to find a window with a U-factor between .27 and .30, and a SHGC rating between .32 and .42.   As we move down south, ENERGY STAR recommends moving toward windows with a higher U factor and lower SHGC to account for the disparity in sunlight and temperature. Taking climate into account is crucial when evaluating which window replacement is right for your home.

U Factor

U factor is essentially the insulation value of a window (the amount of heat that goes in and out.)  A ‘good’ U-factor rating will typically fall between .2 and .3, but the rule of thumb is the lower the U-factor, the less heat is transferred.  When determining the true value of a window’s U-Factor, it’s important that a homeowner look for windows made by a manufacturer that tests the U-Factor of the entire window, not just the glass.  While some companies only test the glass, SoftLite adheres to ENERGY STAR standards, meaning we test the glass, sashes, and frame as well.  It’s important that these steps are taken, as the entire window is ultimately installed in your home- not just the glass. In order to have U-factor approved, SoftLite utilizes an independent third-party NFRC-approved tester to ensure our energy-efficient windows exceed US Energy guidelines.

Solar Heat Gain Coefficient (SHGC)

SHGC is the measure of how much solar heat is absorbed through a window.  Much like U-factor ratings, SHGC ratings fall between 0 and 1.  In a SHGC rating, the lower the number, the lower the amount of radiant heat that can move through the window.  A window with a low SHGC rating will ultimately keep a home cool in the summer, lowering the amount of money a homeowner will have to spend on cooling as well. However, like U-factor, a low SHGC rating may not be ideal for every home and can depend on climate.  For example, a home that sits in a northern region may need a higher SHGC to let in more radiant heat in the wintertime.  Other factors such as nearby trees or the number of windows being installed can impact the ideal SHGC as well.  If your window is under a shaded area, then a higher SHGC may be beneficial, even if you live in a warm climate.

Air Infiltration

Air infiltration ratings are based on the amount of air that seeps through a window.  The lower the infiltration number the better, as the rating reflects the cubic feet of air that can seep through a window per minute.  Infiltration rating standards are determined by the NFRC, who set the maximum air infiltration allowance at 0.3 cubic feet of air infiltration per foot of window per minute.  This means that in order for a 4 foot by 5 foot window to meet NFRC standards, it must allow less than or equal to 6 cubic feet of air infiltration per minute.  The better a window prevents leakage and infiltration, the better insulated a home will be. This means air infiltration efficiency can save a homeowner valuable dollars on their heating and cooling bills every month. Ultimately,  SoftLite windows exceed NFRC standards,  with infiltration ratings delivering results 15-30 times better than the industry standard.

Energy-Efficient Window Dealers

Whether you’re looking to improve your existing windows, or replace them entirely, SoftLite Windows and Doors offers a variety of products guaranteed to exceed industry standards. For over 80 years, homeowners have relied on SoftLite’s ability to manufacture the most reliable, durable, and high-performing windows on the market.  We utilize Low-E glass, ensure industry leading insulation and air infiltration ratings, and offer a multitude of Energy Star-qualified window styles. If you would like to learn more about the benefits of installing our stylish, aesthetic, and efficient windows, contact a dealer near you.