Free Tool — HVAC
Refrigerant Charge Calculator
Estimate refrigerant charge by system tonnage. Covers R-410A, R-22, R-32, and R-134a with GWP and ODP data for EPA 608 exam prep.
Refrigerant Charge Estimator
1 ton = 12,000 BTU/hr
Estimated Charge
7.5 lbs
2.5 lbs/ton × 3 tons
Refrigerant
R-410A
GWP
2088
ODP
0
Status
Being phased down (HFC)
* Estimated charge based on typical lbs/ton ratios. Actual charge depends on line set length, elevation change, and manufacturer specs. Always refer to the equipment nameplate.
For exam practice and estimation only — not a substitute for engineered design, manufacturer data, current codes, or a licensed professional's judgment. Verify all values before relying on them.
EPA 608 Exam Reference
The EPA 608 exam tests your knowledge of refrigerant properties, environmental impact, and handling requirements. Key facts to know:
- R-22 (HCFC-22): Phased out of new equipment production as of 2010. Can no longer be manufactured or imported for use in the US — only reclaimed/recycled R-22 is legal. ODP = 0.055.
- R-410A (HFC): Zero ODP but GWP of 2088. Being phased down under AIM Act. Replaced by R-32 and R-454B in new equipment.
- R-32: Lower GWP (675) than R-410A. Mildly flammable (A2L classification) — requires specific handling procedures.
- Recovery thresholds: Systems with 5+ lbs of refrigerant require evacuation to specified vacuum levels before repair. Know the vacuum level requirements by system pressure type.
Frequently Asked Questions
How many pounds of R-410A per ton?
Industry standard is 2–4 lbs of R-410A per ton of cooling capacity, with 2.5 lbs/ton being a common design target for residential split systems. R-22 averages closer to 3 lbs/ton and R-32 is lower at roughly 2 lbs/ton due to its higher volumetric efficiency. These ratios are for estimation only — actual charge depends on line set length, elevation, and the manufacturer's nameplate specification.
How much refrigerant does a typical residential system hold?
A typical residential split system holds 2–4 lbs of refrigerant per ton of cooling capacity for R-410A. A 3-ton system holds roughly 6–12 lbs depending on line set length and manufacturer specifications. This calculator provides an estimate based on average charge rates — always verify with the equipment nameplate and manufacturer data for service work.
What is the difference between GWP and ODP?
ODP (Ozone Depletion Potential) measures a refrigerant's ability to destroy stratospheric ozone relative to R-11. HCFCs like R-22 have non-zero ODP and are being phased out. GWP (Global Warming Potential) measures greenhouse gas impact relative to CO₂ over 100 years. HFCs like R-410A have zero ODP but high GWP — now being phased down under the AIM Act.
Is R-22 still legal to use?
R-22 production and import ended January 1, 2020. Technicians may still use reclaimed or recycled R-22 to service existing equipment. You cannot use virgin R-22 for new equipment or as a top-off for equipment with unknown leak history. R-22 service work requires EPA 608 Type II certification.
What does the EPA 608 exam cover?
The EPA 608 exam has four sections: Core (refrigerant regulations, environmental impact, safety), Type I (small appliances under 5 lbs), Type II (high-pressure systems like R-22 and R-410A), and Type III (low-pressure systems like R-11 and R-113). Most HVAC technicians take Core + Type II. Technicians who pass all four earn Universal certification.
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Calculate total fall clearance distance for lanyards and SRLs per OSHA 1926.502 — pass/fail by anchor height
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Practice 5 HVAC / EPA 608 exam questions
Real questions — each with an instant AI explanation.
HVAC / EPA 608 · Question 1 of 5
What is the primary effect of Global Warming Potential (GWP) in refrigerants?
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