How is the annualized leak rate calculated?

EPA Section 608 annualizes leaks: leak rate equals refrigerant added divided by full charge, times 365 divided by the days since the last addition, expressed as a percent. This extrapolates a partial-year top-up to a full-year rate.

What are the EPA Section 608 leak-rate thresholds?

For appliances with at least 50 pounds of charge, the repair triggers are 10 percent per year for comfort cooling, 20 percent for commercial refrigeration and 30 percent for industrial process refrigeration. Exceeding the threshold requires repair within 30 days.

What is global warming potential (GWP)?

GWP is how much heat a gas traps relative to carbon dioxide over 100 years. R-410A has a GWP near 2088, so one pound of it leaked is roughly equivalent to 2088 pounds of CO2, which is why high-GWP refrigerants are being phased down.

What is the AIM Act HFC phasedown?

The American Innovation and Manufacturing Act directs the EPA to cut production and import of high-GWP hydrofluorocarbons over time. Chronic leakers on refrigerants like R-404A and R-410A are strong candidates to retrofit to lower-GWP blends such as R-32 or R-454B.

Does the rule apply to small systems?

The Section 608 leak-rate repair mandate applies to appliances containing 50 pounds or more of refrigerant. Smaller systems fall outside the formal trigger, though prompt leak repair remains good practice and venting is always prohibited.

Refrigerant GWP & EPA Section 608 Quantity Calculator

Refrigerant leaks are both a cost and a compliance issue. Under EPA Section 608, commercial systems that leak above a threshold must be repaired within 30 days, and high-GWP refrigerants face phasedown under the AIM Act. This calculator annualizes your leak rate, checks it against the regulatory trigger, and reports the climate impact of the full charge.

How it works

EPA annualizes leaks from the refrigerant added since the last service:

leak_rate% = (added / full_charge) × (365 / days_since_add) × 100

That rate is compared to the threshold for the appliance type: 10 percent comfort cooling, 20 percent commercial refrigeration, 30 percent industrial process refrigeration, for systems holding at least 50 lb. The charge’s climate impact is its CO2-equivalent:

CO2e (lb) = charge_lb × GWP

Worked example

A comfort-cooling system with a 100 lb charge of R-410A receives 8 lb of top-up 90 days after its last service:

leak_rate = (8 / 100) × (365 / 90) × 100 = 8 × 4.056 ≈ 32.4%

That far exceeds the 10 percent comfort-cooling threshold, so a repair is required within 30 days. The full charge represents 100 × 2088 = 208,800 lb of CO2-equivalent, about 95 metric tons.

Tips and notes

The annualizing method means a small top-up over a short interval can imply a high annual rate, which is intentional, it flags fast leaks early. Track each addition with its date so the day count is accurate. Venting refrigerant is always prohibited regardless of charge size, and for systems that repeatedly exceed the threshold, retrofitting to a low-GWP refrigerant often costs less over time than chronic recharging plus the AIM Act supply squeeze on high-GWP gases.