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Office of Sustainability

Windows

Windows

Energy Efficient Windows

cutout of an energy efficient window

When Buying:

Installing new windows can be expensive. Determine whether it will be more cost effective to invest in new energy efficient windows or to make energy upgrades to existing windows.
Determine your Climate Zone to know the window requirements for maximum energy efficiency in your climate.
Look for ENERGY STAR certified windows for your climate zone.

Improve Energy Efficiency of Existing Windows

Window Treatments:

Awnings can reduce solar heat gain in the summer by up to 65% on south-facing windows and 77% on west-facing windows.
Blinds—vertical or horizontal slat-type—are effective at reducing summer heat gain (up to 45% reduction in heat gain), but not winter heat loss.
Drapes and Shades can be closed on summer days to reduce heat gain (up to 33%) and on winter nights to reduce heat loss (up to 10%).

Window Inserts:

Custom-fit panels placed on window interiors can drastically increase the thermal efficiency of single-pane and double-pane windows.
Affordable and easy to install and remove.

Seal Air Leaks:

Sealing air links can save an old home 20% on heating and cooling bills.
Caulk is used to seal air leaks through cracks, gaps, or joints less than 1/4 inch wide between stationary building components and materials.
Use weatherstripping to seal the movable parts of doors and windows. Make sure to choose the proper weatherstripping for different applications.

Office of Sustainability
312-314 Corbett Hall
Orono, Maine 04469-5774
Tel: 207.581.1571
sustainability@maine.edu

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