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Statutory Compliance

EPA Subpart C Leak Rate Calculator

Calculate system leak rates dynamically using the EPA annualized method. Under the AIM Act (40 CFR Part 84 Subpart C), the mandatory tracking threshold dropped from 50 lbs to 15 lbs on January 1, 2026.

Annualized leak rate calculations determine if a commercial refrigeration, comfort cooling, or industrial process system is leaking beyond statutory compliance limits.

Annualized Leak Rate Formula

Leak Rate % = (Lbs Added / Full Charge) * (365 / Days Since Last Addition) * 100
The rule this calculator applies: Since January 1, 2026 the AIM Act (40 CFR Part 84 Subpart C) requires leak repair on appliances holding 15 lbs or more of an HFC or high-GWP substitute, when the annualized rate exceeds 10% comfort cooling, 20% commercial refrigeration or 30% industrial process. Ozone-depleting refrigerants such as R-22 stay under Part 82 at 50 lbs. For what changed, the repair and verification deadlines, the chronic-leaker report and who is exempt, see EPA leak rate thresholds explained.

Frequently Asked Questions

What do I need to enter to get a leak rate?

Three numbers and two choices: the full charge of the appliance in pounds, the pounds of refrigerant added at the last charge, and the number of days since the previous addition. The refrigerant and the appliance class decide which rule and which trigger rate the result is measured against. The rate appears as you type — there is no submit step.

Why does the calculator ask which refrigerant is in the system?

Because the charge at which the rule applies depends on it. An HFC or high-GWP substitute is measured against the 15 lb line in 40 CFR Part 84 Subpart C; R-22 is an ozone-depleting HCFC, is excluded from that rule by 40 CFR 84.106(a)(3)(i), and is measured against the 50 lb line in 40 CFR Part 82 Subpart F. Choosing "Other HFC/HCFC" cannot be resolved to one rule, so the calculator applies the 15 lb line and labels the result as an assumption — check which one your refrigerant is before relying on it.

Does this calculator store my results or need an account?

No to both. The arithmetic runs in your browser, nothing is uploaded, and nothing is kept once you close the tab. It is a scratchpad, not a record. Logging the addition against the equipment record in Equipment Tracker Pro is what produces something you can show later.

Why did the calculator not flag a rate that looks high?

A flag needs two things to be true at once: the annualized rate has to be above the trigger rate for the appliance class you picked, and the full charge has to reach the line at which the rule applies to that refrigerant. A 6 lb system leaking heavily is above the rate and below the charge line, so the leak-repair obligation is not triggered and the calculator does not claim it is.

Why does a comfort cooling result carry an exemption note?

Because residential and light-commercial air conditioning and heat pump systems are carved out of the leak-repair provisions, and the calculator cannot tell from a charge size which side of that line a given unit sits on. It shows the number and says the exemption may apply, rather than suppressing a result that a technician may still want on the record.

Automate Your Compliance Logbooks

Don't calculate leak rates by hand on paper. Equipment Tracker Pro computes EPA Section 608 compliance math on-site, warns you of violations instantly, and keeps every refrigerant addition logged and organized for your compliance records. If you are still choosing a tool, our guide to HVAC equipment tracking software compares the options.