Window Replacement Savings Calculator

Estimate how much an expected reduction in heating and cooling energy use could save each year after window replacement.

Annual heating & cooling electricity use (kWh) Electricity price ($/kWh) Expected HVAC energy reduction (%) Window project cost ($)

Formula

Annual energy saved = HVAC energy use × expected reduction. Annual dollar savings = saved kWh × electricity price. Simple payback = project cost ÷ annual savings.

Use HVAC energy rather than total household energy

Windows mainly affect heating and cooling loads. Using whole-home electricity can exaggerate savings because refrigerators, lighting and electronics are not directly reduced by better windows.

Why window savings vary

Existing window condition and air leakage.
Climate and heating/cooling season length.
Window area and orientation.
U-factor and solar heat gain coefficient.
Installation quality.
Heating and cooling equipment efficiency.

Do not judge windows only by payback

Window projects can also change comfort, condensation, noise and maintenance. This calculator evaluates only a simple energy-savings scenario and does not value those other benefits.