HVAC Compliance Calculator

EPA Refrigerant Leak Rate Calculator

The AIM Act leak repair rule (40 CFR 84.106) took effect January 1, 2026. Enter the charge and the refrigerant you added, and this tool runs the exact EPA formula, checks the 10/20/30 percent thresholds, and lists every deadline you are on the hook for.

Mirroring EPA's own fact sheet language: this information is provided for informational purposes only and should not be relied on for compliance. The regulation of record is 40 CFR part 84, subpart C. For compliance questions EPA lists HFCEmissionsReductions@epa.gov.

Leak Rate Thresholds by Appliance Type

Repairs must be performed by a certified technician (84.106(c)(1)) and only need to bring the leak rate below the applicable threshold (84.106(d)(2)).

Deadlines Once a Threshold Is Exceeded

Deadline clocks are suspended while an appliance is mothballed (evacuated to at least atmospheric pressure and temporarily shut down) and resume when refrigerant is added back (84.106(d)(3)).

How the Two Calculation Methods Work

The formulas live in the definition of leak rate at 40 CFR 84.102, not in 84.106 itself. The definition opens with a constraint that trips people up: "The same method must be used for all appliances subject to the leak repair requirements located at an operating facility." Pick one method per facility, not per unit.

Annualizing Method (84.102, Leak rate (1))

The regulation spells it out in four steps, quoted directly:

"Step 1. Take the number of pounds of refrigerant added to the appliance to return it to a full charge, whether in one addition or in multiple additions related to same leak, and divide it by the number of pounds of refrigerant the appliance normally contains at full charge; Step 2. Take the shorter of the number of days that have passed since the last day refrigerant was added or 365 days and divide that number by 365 days; Step 3. Take the number calculated in Step 1 and divide it by the number calculated in Step 2; and Step 4. Multiply the number calculated in Step 3 by 100 to calculate a percentage."

In algebra, that works out to: leak rate = (lb added ÷ full charge) ÷ (min(days since last addition, 365) ÷ 365) × 100. The min(days, 365) cap means a top-off after 500 quiet days is treated as 365 days, never diluted further. For the first calculation after January 1, 2026, substitute 365 days as the number of days since the last addition (84.106(b)(1)).

Rolling Average Method (84.102, Leak rate (2))

Also quoted directly from the regulation:

"Step 1. Take the sum of the pounds of refrigerant added to the appliance over the previous 365-day period (or over the period that has passed since the last successful follow-up verification test showing all identified leaks in the appliance were repaired, if that period is less than one year); Step 2. Divide the result of Step 1 by the pounds of refrigerant the appliance normally contains at full charge; and Step 3. Multiply the result of Step 2 by 100 to obtain a percentage."

For the first use after January 1, 2026, count the pounds of refrigerant added since January 1, 2026 (84.106(b)(2)). A leak rate calculation is required every time refrigerant is added, unless the addition immediately follows a retrofit or a new installation, or qualifies as a seasonal variance (84.106(b)). Purged refrigerant that is destroyed at a verifiable destruction efficiency of 98 percent or greater does not count toward the rate (84.106(k)).

Worked Example: Same Leak, Two Very Different Numbers

A commercial appliance normally holds 100 lb at full charge. You add 15 lb to return it to full charge, 92 days after the last addition.

Annualizing: Step 1: 15 ÷ 100 = 0.15. Step 2: min(92, 365) ÷ 365 = 0.252. Step 3: 0.15 ÷ 0.252 = 0.595. Step 4: 0.595 × 100 = 59.5% per year. That exceeds every threshold in 84.106(c)(2).

Rolling average: if that 15 lb is the only refrigerant added in the trailing 365 days, the rate is 15 ÷ 100 × 100 = 15% per year. Below the 20% commercial refrigeration threshold, above the 10% comfort cooling threshold. Same leak event, and the method choice decides whether a 30-day repair clock starts. The annualizing method reacts fast to a fresh leak; the rolling average smooths it across the year. This example is our own construction to illustrate the formulas; the regulation and EPA's fact sheet do not publish a numeric example.

AIM Act Rule (84.106) vs Section 608 Rule (82.157)

Both leak repair rules are in force at once, split by refrigerant. HFC appliances follow 40 CFR 84.106; ODS appliances (R-22 and other CFC/HCFC systems) follow 40 CFR 82.157. The 2016 update to Section 608 had extended leak repair to HFC appliances at 50 lb, the 2020 rollback rescinded that, and the AIM Act ER&R rule reinstates HFC coverage at a tighter 15 lb trigger effective January 1, 2026.

Which Refrigerants Are Covered

The applicability test in 40 CFR 84.106(a) has a nuance that catches even experienced techs. The GWP-greater-than-53 test applies only to substitutes, and EPA defines a substitute as a substance that itself contains no HFC and no ODS (84.102). Any refrigerant containing any HFC at all is covered under 84.106(a)(1) no matter how low the blend GWP is. R-454B (GWP 465 per EPA's Technology Transitions reference table) is covered because it contains HFC-32. So are R-454C (GWP 146) and R-513A (GWP 630). The GWP escape hatch only exists for non-HFC refrigerants: HFOs like R-1234yf, hydrocarbons like R-290, CO2, and ammonia, all with GWPs at or below 53 per Table 1 to 40 CFR 84.64(b).

The GWP values the rule uses are the AIM Act exchange values in Appendix A to part 84, which are numerically identical to the IPCC AR4 100-year GWPs. Blend GWPs are the mass-weighted sum of the constituents per 40 CFR 84.64(b). The lowest exchange value assigned to any regulated substance is 53 (HFC-152), which is where the cutoff comes from. HFC-152a (GWP 124) is itself a regulated substance, so it is covered despite the low number.

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