Air Sealing Savings Calculator

Air sealing involves closing gaps, cracks, and openings in a home's building envelope — places like around windows, doors, electrical outlets, and attic penetrations. These leaks allow conditioned air to escape and outside air to infiltrate, forcing your heating and cooling system to work harder. Reducing infiltration directly cuts the energy needed to maintain a comfortable indoor temperature.

Heating Degree Days measure how cold your climate is over the course of a year — specifically, the cumulative degrees that daily average temperatures fall below 65°F. You can find your local HDD from the National Oceanic and Atmospheric Administration (NOAA) website or by searching for your city's climate data. Higher HDD means colder winters and greater potential savings from air sealing.

Older, leaky homes can have ACH values of 1.0 or higher, while average existing homes are typically 0.4–0.8 ACH. Energy Star certified new homes target around 0.15–0.25 ACH. After professional air sealing, many existing homes can reach 0.2–0.35 ACH, which can yield significant energy savings.

This calculator provides a reasonable engineering estimate based on your home's volume, infiltration rate, climate, and fuel costs. Actual savings depend on factors like occupant behavior, existing insulation levels, HVAC equipment, and the quality of air sealing work performed. A blower door test by a certified energy auditor gives the most precise measurement of your home's actual leakage.

Natural gas is typically priced per therm. As of recent averages, US residential natural gas costs roughly $1.00–$1.80 per therm, though prices vary significantly by region and season. Check your utility bill or contact your local gas provider for the most current rate in your area.

Yes — this calculator focuses on heating energy (using HDD), but air sealing delivers similar benefits in summer by preventing hot, humid outdoor air from entering your home and cooled air from escaping. In hot climates, cooling savings can match or exceed heating savings. For a full picture, you can also estimate cooling savings using Cooling Degree Days (CDD).

AFUE stands for Annual Fuel Utilization Efficiency — it measures what percentage of fuel is converted to usable heat. Older furnaces may be 60–70% efficient, standard furnaces are around 80%, and high-efficiency condensing furnaces reach 90–98%. You can find your furnace's AFUE on its yellow EnergyGuide label or in the owner's manual.

By burning less fuel to heat your home, air sealing directly reduces carbon dioxide (CO₂) and other greenhouse gas emissions from your heating system. Natural gas produces about 117 lbs of CO₂ per MMBtu, fuel oil around 161 lbs, and propane roughly 139 lbs. Even modest reductions in heating energy use can eliminate hundreds or thousands of pounds of CO₂ annually.