About HVAC PT Charts
A field reference for HVAC professionals: verified pressure-temperature charts for 60 refrigerants, plus calculators and guides for the daily charging, diagnostic, and retrofit work that depends on them.
What HVAC PT Charts is
HVAC PT Charts is a free reference and tooling resource for refrigerant service technicians, equipment specifiers, and HVAC engineers. The site covers every refrigerant a technician is likely to encounter in modern service — from current A2L refrigerants (R-32, R-454B, R-454C, R-1234yf) to legacy HCFCs still in service (R-22, R-123) to industrial naturals (R-717 ammonia, R-744 CO₂, R-290 propane).
| Refrigerant detail pages | 60 | Full PT chart, properties, safety class, retrofit paths |
| Calculators | 9 | PT, superheat, subcooling, combined, system diagnostic, charge, saturation properties, PT comparison, retrofit compatibility |
| Long-form guides | 5 | PT chart reading, SH/SC fundamentals, high head pressure diagnosis, GWP rankings, safety classifications |
| Operating-pressure references | 9 | R-410A, R-22, R-32, R-454B, R-134a, R-404A, R-407C, R-454C, R-744 |
| Pair comparisons | 13 | R-22 vs R-410A, R-32 vs R-410A, R-410A vs R-454B, plus 10 other retrofit / transition decisions |
How the data is built
Saturation data for the 60 refrigerants in the dataset comes from one of two primary-source paths.
| Source path | Refrigerants | Method |
|---|---|---|
| CoolProp 7.2.0 REFPROP-compatible Helmholtz EOS | ~50 | Saturation pressures are computed with CoolProp at every °F from −40 to 150 (or the refrigerant's critical temperature, whichever is lower). |
| Manufacturer datasheets Honeywell, Chemours, Arkema, AGC | ~10 | For blends CoolProp doesn't model (R-448A, R-450A, R-1336mzz(Z), etc.) values come from the named manufacturer datasheet with the URL recorded per refrigerant. When transcription is pending, the page displays an honest disclosure with the source citation — never a fabricated value. |
Values are computed with the open-source CoolProp library (version shown on each chart) or transcribed from the manufacturer's published PT chart, and the build checks them against reference values (R-22 = 121.44 PSIG at 70°F, R-410A = 201.76 PSIG at 70°F, etc.). If any value drifts more than ±5%, or if any saturation pressure exceeds the critical pressure (physically impossible), the build fails and the page is never published.
How the data stays correct
Every safety classification is stored as a fixed value that the page can only display, never guess — so a refrigerant can't be shown with the wrong class. The reference numbers on each page are pulled directly from the verified dataset, and the writing for one refrigerant can never appear on another refrigerant's page.
- No fabricated PT values. Every saturation pressure comes from CoolProp or a named manufacturer datasheet. When source data isn't available, the page shows an honest disclosure naming the missing source, not a guess.
- No mixed-up copy. The writing specific to one refrigerant appears only on that refrigerant's page.
- Safety class can't be misdisplayed. R-32 always shows A2L; the classification is fixed in the verified dataset and simply rendered, never inferred.
- Every claim has a source. Inline citations on each refrigerant page and a provenance footer on every page.
- The build blocks bad data. If PT data drifts outside ±5% of reference values, or if any saturation pressure exceeds the critical pressure, the build fails before anything is published.
Editorial principles
The structural sections of each page — PT chart, properties grid, comparison cards — are drawn from the verified dataset, while the written context (history, applications, retrofit guidance, service notes) is authored separately for each refrigerant. When that written context hasn't been completed for a refrigerant, the data sections still appear and the narrative sections are simply omitted — never filled with boilerplate.
- No paragraph over 3 sentences. Information density is high; text walls are not.
- Every factual claim cites a source from the source registry.
- Reference values (NBP, Tcrit, GWP, etc.) come from the data layer, not from prose retyping.
- No fake author personas. Author = the Organization.
- No emoji as decoration. Use icons (lucide-react) when a visual marker is needed.
- No paywalls, no signup, no email harvesting. Display advertising via Raptive supports the cost of keeping the dataset free.
Open data
The full PT chart for every refrigerant is downloadable as CSV or JSON from the refrigerant's detail page footer. Our text and the CoolProp-computed data are licensed under Creative Commons Attribution 4.0; the manufacturer-published tables (R-438A, R-448A and R-514A) keep their publisher's terms. Use the CC BY data for HVAC service apps, training simulators, OEM internal tooling, academic research, building-energy modeling, or any other purpose — attribute the source and the underlying primary source for the specific values (CoolProp citation, manufacturer datasheet citation).
Every PT chart page has CSV and JSON downloads — at /data/refrigerant/<slug>/json and /csv — our computed tables under CC BY 4.0, the manufacturer-published tables under their publisher's terms.
What this site is not
HVAC PT Charts is reference material, not replacement for formal HVAC training, equipment OEM service literature, or jurisdictional code compliance. A few intentional non-features:
- Not a substitute for EPA Section 608 certification. Legal handling of refrigerants in the US requires Section 608 certification. The site does not replace the formal training pathway.
- Not a substitute for equipment OEM service literature. Reference targets here (target superheat / subcooling, charge nameplate values) are generic. Always defer to the equipment OEM's charging procedure for the specific equipment.
- Not a Manual J load calculator. Heat load and equipment sizing belong in ACCA Manual J / S / D software (Wrightsoft, Elite, CoolCalc). This site covers refrigerant-side service measurement, not upstream load calculation.
- Not a live refrigerant price feed. Distributor pricing changes with AIM Act allocations, weather, and import dynamics. Use your distributor for current quotes.
- No user accounts, no signup, no chat AI bolted on top. The site is what it is: structured data, calculators, and reference guides. Visit, look up what you need, leave.