The recently passed Economic Stimulus Package (the American Recovery and Reinvestment Act of 2009) includes Federal tax credits that encourage homeowners to make energy efficient improvements to their homes. Replacing windows and doors with energy efficient Infinity products qualifies for this tax credit!
To qualify, a high level of energy efficiency is required. Infinity from Marvin products meet those qualifications with high performance Low-E 366 glass. Low-E 366 is available on all Infinity windows and doors, so homeowners can increase the energy efficiency of their home and qualify for the $1,500 tax credit!
U-Factor
The rate of heat loss is indicated in terms of the U-factor (U-value) of a window assembly. The insulating value is indicated by the R-value which is the inverse of the U-value. The lower the U-value, the greater a window's resistance to heat flow and the better its insulating value. To qualify for the tax credit, the U-Factor must be .30 or lower. The lower the U-Factor, the better overall performance of the window.
Northern Climate: Select windows with a U-factor of 0.35 or less. If air conditioning loads are minimal, windows with U-factors as high as 0.40 are also energy-efficient if the Solar Heat Gain Coefficient is 0.50 or higher. Some double-glazed low-e products have U-factors below 0.30. Some three-layer products have U-factors as low as 0.15.
North/Central Climate: Select windows with a U-factor of 0.40 or less. The larger your heating bill, the more important a low U-factor becomes.
South/Central Climate: Select windows with a U-factor of 0.40 or less. The larger your heating bill, the more important a low U-factor becomes.
Southern Climate: A low U-factor is useful during cold days when heating is needed. A low U-factor is also helpful during hot days when it is important to keep the heat out, but it is less important than SHGC in warm climates. Select windows with a U-factor lower than 0.75 and preferably lower than 0.60.
See www.efficientwindows.org/ufactor.cfm.
Solar Heat Gain Coefficient (SHGC)
The SHGC is the fraction of incident solar radiation admitted through a window, both admitted through a window, both directly transmitted, and absorbed and subsequently released inward. SHGC is expressed as a number between 0 and 1. The lower a window's solar heat gain coefficient, the less solar heat it transmits.
Northern Climate: To reduce heating, select the highest SHGC you can find (usually 0.30- 0.60 for the U-factor ranges required in colder climates) so that winter solar gains can offset a portion of the heating energy need. If cooling is a significant concern, select windows with a SHGC less than 0.55. Use RESFEN to understand trade-offs.
North/Central Climate: If you have significant air conditioning costs or summer overheating problems, look for SHGC values of 0.40 or less. If you have moderate air conditioning requirements, select windows with a SHGC of 0.55 or less. While windows with lower SHGC values reduce summer cooling and overheating, they also reduce free winter solar heat gain. Use a computer program such as RESFEN to understand heating and cooling trade-offs.
South/Central Climate: If you have moderate air conditioning requirements, select windows with a SHGC of 0.55 or less. While windows with lower SHGC values reduce summer cooling and overheating, they also reduce free winter solar heat gain. Use a computer program such as RESFEN to understand heating and cooling trade-offs. Southern Climate: A low SHGC is the most important window property in warm climates. Select windows with a SHGC less than 0.40.
See www.efficientwindows.org/shgc.cfm.
NOTE: U-Factor and SHGC figures should be determined by an independent rating council like the NFRC (National Fenestration Rating Council); see www.nfrc.org. NFRC provides accurate information to measure and compare energy performance of windows, doors and skylights.
This summary information is provided as a convenience and may not be relied upon as a substitute for professional tax advice. Infinity and Exterior Home Improvement disclaim all responsibility for determining whether a particular product qualifies for this or any other tax credit. All purchasers are advised to consult a professional tax advisor to determine whether the products they purchase qualify for the tax credit. More information is available at www.energystar.gov/taxcredit.