The Interactive ASHRAE
Psychrometric Chart
Plot moist air states, chain air-handling processes and export professional reports — all in your browser, in I-P units (°F, CFM, grains, BTU) per ASHRAE Fundamentals 2021. Free version available instantly.
Why PsychroView instead of Excel or legacy tools?
Legacy solutions
- ✗ Excel spreadsheets — no chart, formula errors slip through
- ✗ Desktop software — installation, license management, dated UI
- ✗ Single-purpose online calculators — one process, no export
PsychroView
- ✓ Interactive psychrometric chart right in the browser
- ✓ The full air-handling sequence in one calculation (14 processes)
- ✓ Vector PDF and DXF for technical reports
Psychrometric calculation tools for HVAC design
Everything you need for psychrometric calculations in HVAC projects.
Psychrometric chart
Interactive ASHRAE-style Carrier chart (and Mollier) with isolines, zoom, pan and dark mode. Full control over axis range and step, in I-P or SI units.
Process chain
Heating, cooling, humidification, energy recovery and mixing in one continuous calculation. Multiple process sets to compare variants side by side.
Export to PDF, DXF and more
Detailed reports with a results table and chart for project documentation. Vector PDF, plus DXF for AutoCAD, Excel, Word and HTML.
Cloud storage
Projects sync to the cloud automatically and securely. Access them from any device.
Share by link
Generate a read-only link and share results with colleagues or clients — no sign-up required.
Automatic target iteration
PsychroView iterates the process chain to hit your target air state — from the required air parameters combined with cooling load, moisture load or heat loss.
Drag points on the chart
Grab any state point and drag it — downstream processes and all results recalculate instantly.
Example projects
Ready-made project templates you can duplicate as the starting point for your own project.
Climate data
Design input values from freely available weather databases — plus import of your own climate data (JSON or CSV).
Calculations Verified Against ASHRAE Fundamentals 2021
Psychrometric calculations are implemented precisely per Chapter 1 of the ASHRAE Handbook — Fundamentals, including the real-gas correction (enhancement factor), with results available in I-P or SI units. Deviations against the ASHRAE reference tables stay below 0.02 % for saturation pressure, 0.08 % for humidity ratio and 0.043 Btu/lb for enthalpy — well within the accuracy of typical measuring instruments.
Read the full conformance documentation →Frequently Asked Questions
Is PsychroView free to use? +
Yes — basic access to the psychrometric chart is free and requires no registration. More features available with complete registration.
What standard are the calculations based on? +
Calculations follow ASHRAE Fundamentals 2021, Chapter 1 (SI), using the Hyland-Wexler equations. The maximum deviation of saturation pressure against the ASHRAE reference tables is 0.041 %.
Can I export the psychrometric chart to CAD? +
Yes. PsychroView exports the chart as DXF for AutoCAD, as well as vector PDF and PNG at any resolution. Results tables can also be exported to Excel, Word and HTML.
How many processes can I chain together? +
Without registration you can draw two processes. With registration you get more processes.
What is a psychrometric chart? +
A psychrometric chart is a graphical representation of the properties of moist air — dry-bulb temperature, humidity ratio, enthalpy and relative humidity. HVAC engineers use it to plot and size air-handling processes such as heating, cooling, humidification and dehumidification.
What is the difference between a psychrometric chart and a Mollier diagram? +
Both show the same thermodynamic data for moist air; they differ in axis convention. The Mollier h-x diagram, common in Europe, is effectively a rotated version of the ASHRAE-style psychrometric chart used in North America. PsychroView lets you work in either view.
Start now — it's free
No credit card. No installation. Open the app and start calculating.