Free Compliance Tools
R-407C Leak Rate Calculator
Free EPA-compliant tool · Both calculation methods · Updated for the 2026 mandate
R-407C is the refrigerant most R-22 systems were converted to when the HCFC phaseout made R-22 scarce — same high-pressure class, compatible operating envelope, straightforward retrofit. Compliance-wise, that conversion does something many owners miss: it moves the appliance out of the old Section 608 50-lb rule and into AIM Act Subpart C, where leak-rate tracking starts at just 15 pounds of charge. If you service retrofitted equipment, this calculator runs the exact math the 2026 rule requires.
1,774
A1
0
R-32 / R-125 / R-134a (23/25/52)
Calculate Your R-407C Leak Rate
Equipment Setup
Typical range: 5–30 lbs (splits/rooftops), 30–150 lbs (larger commercial systems)
Log Refrigerant Addition
Annualizing Method
rate = (lbs_added ÷ full_charge) × (365 ÷ D) × 100
Where D = days since previous addition (or 365 for the first event after Jan 1, 2026). Projects a single addition over a full year.
R-407C leak rate (annualizing)
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ADD R-407C SERVICE EVENTS TO CALCULATE
Comfort Cooling · 10% EPA threshold
0.0 lbs
0%
of 125% threshold
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R-407C Service Events
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Enter an R-407C addition above to see your EPA-compliant leak rate calculation in real time.
Track R-407C Compliance Automatically
Stop calculating by hand. Ref LeakLog automates R-407C leak rate tracking, repair workflows, audit-ready reports, and team management for the 2026 mandate.
Start Your 14-Day Free TrialR-407C Compliance Under the 2026 Rule
R-407C systems with ≥15 lbs of charge fall under Subpart C leak-rate tracking as of January 1, 2026 (GWP 1,774 — far above the rule's 53-GWP test)
Comfort cooling threshold: 10% annual leak rate; commercial refrigeration: 20%
An R-22 → R-407C retrofit flips the regime: the appliance leaves 40 CFR 82.157 (50-lb floor) and enters Subpart C (15-lb floor)
The refrigerant added immediately following a retrofit is excluded from the leak-rate calculation under §84.106(b) — but the exclusion must be documented
After a retrofit, the full charge must be redetermined for the new refrigerant — it is the denominator of every future leak rate
Regulatory Status
HFC blend subject to the AIM Act phase-down. The most common retrofit destination for R-22 comfort-cooling systems — same high-pressure appliance class (40 CFR 82.152 names them side by side). Appliances with ≥15 lbs fall under Subpart C leak-repair as of January 1, 2026.
R-407C sits mid-pack in the phase-down: its GWP of 1,774 is below R-410A's, so it consumes fewer allowances per pound, but it's not a long-term refrigerant either. It exists in the field mostly as the bridge that kept R-22 equipment running — and every one of those retrofitted systems is now a Subpart C appliance.
Common Applications
- R-22 retrofits in comfort cooling and light commercial
- Packaged rooftop units
- Split-system air conditioners
- Water chillers
- Medium-temperature commercial refrigeration
Frequently Asked Questions
What is the EPA leak rate threshold for R-407C systems?
R-407C systems used for comfort cooling have a 10% annual leak rate threshold under 40 CFR Part 84, Subpart C; commercial refrigeration applications have a 20% threshold and industrial process refrigeration 30%. Any R-407C appliance with a full charge of 15 pounds or more is covered — exceeding the threshold triggers the 30-day repair deadline and verification test requirements.
I retrofitted from R-22 to R-407C — which EPA rule applies now?
Subpart C, the 2026 rule. Before the retrofit, the appliance followed 40 CFR 82.157, which only applies at 50 or more pounds of ODS refrigerant. After the retrofit it contains no ozone-depleting substance, so §82.157 stops applying — and Subpart C picks it up at 15 pounds or more. Practically, that means a mid-size retrofitted system may have leak-repair obligations today that it never had on R-22.
Does the first charge after a retrofit count toward my leak rate?
No. Under §84.106(b), the leak rate is not calculated for an addition made immediately following a retrofit — that charge establishes the new baseline rather than measuring a leak. The addition still goes in the service records with the exclusion noted, and the appliance's full charge must be redetermined for the new refrigerant. Every subsequent addition feeds the leak-rate math normally.
What is R-407C's GWP?
1,774. That's the mass-fraction sum EPA's method prescribes (40 CFR 84.64(b)): 23% R-32 (GWP 675) + 25% R-125 (GWP 3,500) + 52% R-134a (GWP 1,430) = 1,773.85, which rounds to 1,774. Being far above the 53-GWP test, R-407C appliances at 15 lbs or more are squarely inside Subpart C.
Is R-407C being phased out?
It's being phased down, not banned. As an HFC blend it's subject to AIM Act production allocations, and its mid-range GWP means it will stay serviceable longer than R-404A but face more supply pressure than low-GWP options like R-454B. Existing R-407C systems — including retrofitted former R-22 equipment — remain legal to operate and service.
Don't Calculate By Hand
Ref LeakLog automates R-407C leak rate tracking for your entire fleet — calculations, repair workflows, deadline reminders, and audit-ready PDF reports. The rule has been in effect since January 1, 2026.
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