R-454B · R-32 · R-410A
Charge A2L systems by the numbers.
Gauge pressure and line temp in, superheat or subcooling out, with R-454B bubble and dew points handled correctly. Two inputs. One answer. Under 30 seconds.
- Free
- iPhone & iPad
- Works offline
- No account
Who it’s for
Making the jump from R-410A? So is everyone.
Built for residential HVAC techs and apprentices moving to R-454B and R-32. The new refrigerants need different PT references, glide handling, and room safety math than what you have been running for a decade. This puts all of it on your phone instead of scattered across manufacturer PDFs.
- Superheat and subcooling in seconds. Enter suction or liquid pressure in psig and line temp in °F. Get the actual number with typical-range context and an optional OEM target comparison.
- Glide handled right. R-454B superheat uses dew point, subcooling uses bubble point, automatically. The app will not let you mix them up.
- Max allowable charge from room dimensions. Length, width, and mount location in. Max A2L charge in pounds out, for floor, wall, or ceiling units.
- Active mitigation toggle. Systems with leak detection and response controls get the expanded limit. The passive number stays on screen for reference.
- PT tables built in. R-454B, R-32, and R-410A data ship inside the app. Basements, mechanical rooms, rooftops. Zero bars, full function.
- A2L quick reference. Refrigerant comparison, safety rules, and a bubble-and-dew explainer. The cheat sheet stays in your pocket.
- PDF job reports. Export any calc as a one-page PDF with your company name, tech name, and license number. Generated entirely on the device.
- History that writes the ticket. Every calc auto-saves with a timestamp and optional job label. Pull it back up at the truck.
The numbers behind the numbers
Sourced data, shown sources.
- Max charge formula: structured per UL 60335-2-40 / ASHRAE Standard 15.2, with the attribution shown on every result and PDF.
- Flammability limits: LFL values from ASHRAE 34-2022 (R-454B 0.303 kg/m³, R-32 0.307 kg/m³), with installation heights for floor, wall, and ceiling mounts.
- Active mitigation: expanded limit attributed to UL 60335-2-40 Ed. 3 Annex GG.
- PT data sources shown on every result: Chemours Opteon XL41 (NIST REFPROP 10.0) for R-454B, Daikin / Hudson Technologies (NIST) for R-32, National Refrigerants Reference Guide 7th Ed. for R-410A.
- Field units throughout: °F, psig, square feet, pounds.
- Honest results: typical ranges are shown for context, never pass-fail badges, and every result carries a disclaimer. It is a calculation aid, not a substitute for the OEM charging procedure or code compliance.
Get it
Free. On your gauges’ side before the next A2L call.