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Energy Savings Helper

High Performance Windows

Calculate annual energy and cost savings from upgrading to ENERGY STAR High Performance Windows in Illinois using the IL TRM v14.0 deemed savings methodology.

Your Home
Select the climate zone closest to your location. Each zone has different heating and cooling savings values.
Select your home's heating and cooling equipment. Savings values assume central air conditioning — homes without AC will see somewhat lower electric savings.
Window Details
Double pane = two layers of glass (standard since the 1990s). Single pane = one layer, common in homes built before about 1980. Replacing single pane saves much more.
Total square footage of window area being replaced. Savings assume the new windows are ENERGY STAR high-performance models (U-factor 0.22-0.25 or better — ask your installer); standard replacement windows won't achieve these savings.

Frequently Asked Questions