Psychrometric Chart Calculator Excel |best| Jun 2026

[ W = 0.62198 \cdot \fracp_wP - p_w ] where ( P ) is total atmospheric pressure (typically 101.325 kPa at sea level). The factor 0.62198 is the ratio of molecular weights of water (18.01528) to dry air (28.9645).

ASHRAE TC 9.9 recommends strict dew point ranges (e.g., 41.9°F to 59°F). Use your calculator to convert sensor RH/temperature into dew point and trigger automated alerts. psychrometric chart calculator excel

(Note: Professional engineers often use the more complex ASHRAE formulation for higher precision across wider temperature ranges.) [ W = 0

Proprietary software often uses "black box" algorithms. In Excel, you see every formula. You can validate the calculations against ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) standards. Use your calculator to convert sensor RH/temperature into

Add IFERROR wrappers. Use conditional formatting to highlight when RH exceeds 100% (fog region) or drops below 0%.

| Feature | Excel Calculator | Dedicated Software (e.g., PsychroChart, CoolProp) | |---------|----------------|--------------------------------------------------| | Cost | Free (with Excel) | $100–$1000+ | | Transparency | Full formulas visible | Black‑box models | | Customization | Endless (add duct sizing, cost, controls) | Limited to built‑in functions | | Integration | Link to other spreadsheets (load calc, energy models) | Export/import only | | Accuracy | High (same ASHRAE equations) | High | | Ease of sharing | Excel file via email | Requires software installation |

(m³/kg dry air )