HVAC Pressure-Temperature Charts
Verified saturation data for 61 refrigerants — every value sourced and cited. 9 calculators, 13 pair comparisons, 4 long-form guides. No signup, no paywall, CC BY 4.0.
Quick reference — most-used refrigerants at 70°F
Saturation pressure at 70°F. Click any card for the full chart, properties, and retrofit guidance.
Find a refrigerant
All 61 refrigerants in the dataset. Filter by type, safety class, GWP bucket, or search by name / trade name / chemistry.
Calculators
9 calculators built on the verified dataset. Bubble vs dew handled automatically for zeotropic blends. Imperial and metric units.
Charging and diagnostic
Superheat
Suction PSIG + line °F → superheat with diagnostic context.
Subcooling
Liquid line PSIG + °F → subcooling with overcharge / undercharge interpretation.
Combined SH / SC / PT
Both sides + pattern-matching diagnostic banner.
System Pressure Diagnostic
8-input expert system: flagged findings with evidence and ordered recommendations.
Refrigerant Charge
Line-set length adjustment to nameplate. Per-foot oz from CoolProp liquid density.
Lookup and reference
Refrigerant comparisons
Direct pair comparisons for the most-asked decisions. 13 pair pages total covering residential, commercial refrigeration, chillers, and naturals.
R-22 vs R-410A
Homeowner replacement decision — why retrofit isn't a drop-in.
R-32 vs R-454B
The two leading R-410A replacements — decided largely by OEM preference.
R-410A vs R-454B
Direct A2L replacement for new equipment installs.
R-22 vs R-32
Legacy HCFC vs modern A2L — full replacement only.
R-134a vs R-513A
Chiller drop-in: 56% GWP reduction, same A1, same POE oil.
R-744 vs R-290
CO₂ transcritical vs propane A3 charge-limited — the natural refrigerant choice.
Refrigerant comparison guide — the framework behind these decisions
Operating pressure references
Typical suction and discharge pressures by ambient temperature, with diagnostic procedure. For field-troubleshooting reference.
Long-form guides
Conceptual references for the methods behind the calculators and the decisions behind the comparisons.
Refrigerant Comparison Guide
Framework for choosing between refrigerants across 5 axes — thermo, safety, environment, regulation, practical.
Superheat & Subcooling Fundamentals
What they are, how to measure, target values, the 4 diagnostic patterns.
How to Read a PT Chart
Bubble vs dew, glide, critical point truncation, common pitfalls.
High Head Pressure Causes
Diagnostic decision tree for high-side pressure problems.
About this site
Six guarantees behind every number on every page.
Verified data
CoolProp 7.2.0 (REFPROP-compatible Helmholtz EOS), plus named manufacturer datasheets (Honeywell, Chemours, Arkema, AGC) for blends CoolProp doesn't model.
One source of truth
Every chart, every calculator, every comparison reads from the same Zod-validated refrigerant record. No copies, no drift.
Structural safety class
A1 / A2L / A3 / B1 / B2L comes from a typed enum — impossible to mislabel R-32 as A1 even on pages without editorial content yet.
IPCC AR5 GWP
The figure EPA uses for the AIM Act 700-GWP threshold. AR6 values shown where they differ meaningfully.
No signup, no paywall
Open access to every chart, calculator, and dataset. Site is ad-supported via Raptive — no email gates, no popups, no required accounts.
Downloadable dataset
Full PT data for every refrigerant available as CSV or JSON under CC BY 4.0. Free for any use with attribution.