A2L Charge Limit Calculator

How much A2L refrigerant can go in a room? Punch in the room size — get the max charge in 30 seconds.

Charge-limit quick check

Code (UL 60335-2-40) limits how much A2L can go into a room: max charge ≈ room volume × LFL × 0.25 safety factor. Punch in the room to sanity-check a system charge.

Room length (ft)

Room width (ft)

Ceiling height (ft)

Refrigerant

LFL override (kg/m³, optional)

Lowest gas-in-air amount that can ignite — check the refrigerant's safety data sheet (SDS).

System charge (lbs, optional)

Simplified per the UL 60335-2-40 concept — real code calculations include more factors. LFL values vary slightly by source; the override field lets you use your refrigerant's SDS value. Always verify against the OEM manual and local code.

Retooling for A2L?

Run the full 21-point readiness checklist — tools, training, and safety for R-454B and R-32 work.

Open the checklist

Sizing charges all day? Keep the schedule full too.

Shops are winning A2L changeout jobs right now. See how CoolBooked fills your calendar with them automatically — no missed calls, no paperwork.

Learn about CoolBooked