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Home Air Sealing Savings Calculator

Estimate energy savings from reducing air leakage (infiltration) in your home.

Result

Estimated Annual Savings
$252
Air Leakage Reduction
40%

Assumes air leakage (infiltration) accounts for roughly a third of a typical home's heating/cooling load, a commonly cited building-science estimate - actual impact depends on your specific home and climate. This is a separate mechanism from insulation R-value: air sealing stops drafts, while insulation slows heat conduction through the material itself.

About the Air Sealing Savings

This calculator estimates the annual dollar savings from sealing air leaks in a home, based on a before-and-after air-tightness measurement expressed as ACH50 (air changes per hour at 50 pascals of pressure, the standard blower door test metric). It's built for homeowners who've had a blower door test done, or who are comparing a current leaky-home estimate against a sealing contractor's target, and want to translate that improvement into an expected cost reduction on the heating and cooling bill.

How It Works

You enter your home's current ACH50 reading, a target ACH50 after air sealing work, and your annual heating and cooling cost. The calculator computes the percentage reduction in air leakage between the two ACH50 values, then applies that percentage to the portion of your energy bill assumed to come from infiltration (air leaking in and out through gaps and cracks) rather than from conduction through walls, windows, and insulation.

Reduction fraction = (Current ACH50 - Target ACH50) / Current ACH50 (floored at 0); Annual Savings = Annual Heating+Cooling Cost x 0.35 x Reduction fraction

Formula & Methodology

First, the calculator finds how much your ACH50 is expected to drop in relative terms: subtract the target ACH50 from the current one, then divide by the current ACH50. That gives the fraction of your air leakage being eliminated. The calculator then assumes that air leakage (infiltration) accounts for 35% of a typical home's total heating and cooling energy use, a commonly cited building-science estimate, with the remainder attributed to conduction through the building envelope. Multiplying your annual heating and cooling cost by 0.35 and then by the reduction fraction gives the estimated annual savings.

Examples

Typical older home sealing project

A home starts at ACH50 10 and is sealed down to ACH50 6, a 40% reduction in air leakage. With a $1,800 annual heating and cooling bill, the calculator estimates $252 in annual savings.

Aggressive sealing on a leakier home

A drafty home measured at ACH50 12 is sealed down to ACH50 5, a 58.3% leakage reduction. On a $2,400 annual heating and cooling bill, that works out to roughly $490 in estimated annual savings.

Advantages

  • Converts a technical blower door test result (ACH50) directly into a dollar figure homeowners can weigh against sealing project costs.
  • Separates air sealing's impact from insulation's impact, avoiding double-counting savings that overlap with other home efficiency calculators.
  • Guards against nonsensical results by flooring the reduction fraction at zero when the target ACH50 isn't actually an improvement.

Common Mistakes

  • Using a rough guess instead of an actual blower door test number for current ACH50, which can throw off the savings estimate substantially since air leakage varies enormously between homes.
  • Assuming the estimated savings will show up entirely in a single utility bill, when heating and cooling costs (and therefore the dollar savings) vary by season and weather.
  • Treating the 35% infiltration share as an exact figure for your specific house rather than a general estimate, when your home's actual mix of leakage versus conduction losses could differ.

Edge Cases to Watch For

  • If current ACH50 is zero or negative, the calculator returns an error rather than dividing by zero.
  • The reduction fraction is floored at zero, so entering a target ACH50 higher than your current reading (a home that's getting leakier, not tighter) produces zero estimated savings rather than a negative number.
  • The 35% infiltration share is a fixed assumption, not something the calculator derives from your specific home; older, leakier homes or homes in milder climates may see infiltration account for a meaningfully different share of the bill.
  • This estimate is separate from insulation upgrades: air sealing addresses drafts and leakage paths, while R-value improvements address heat conducting through walls, ceilings, and floors, so this calculator won't capture savings from insulation work done at the same time.

Common Use Cases

  • Homeowners deciding whether a quoted air sealing project is worth the cost based on projected annual bill savings.
  • People who've had a professional blower door test done and want to translate the ACH50 numbers into a savings estimate they can act on.
  • Energy auditors or contractors giving clients a quick, defensible ballpark savings figure to accompany a sealing recommendation.
Written & fact-checked by the Calculateus TeamLast updated August 5, 2026How we verify our formulas

Frequently asked questions

What's the difference between air sealing and insulation?

Insulation slows heat from conducting through walls, ceilings, and floors. Air sealing stops warm or cool conditioned air from literally leaking out through gaps, cracks, and penetrations (and outside air leaking in) - a well-insulated home with poor air sealing can still lose significant energy, which is why building scientists recommend 'seal first, then insulate.'

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Conclusion

Air sealing addresses a genuinely large and often overlooked share of home energy loss, but the actual savings depend on your specific home's construction, climate, and how much of your bill infiltration really accounts for. Use this estimate as a planning figure alongside a professional energy audit, not as a guaranteed result.