Formula & worked example
ṁwater=ṁdry-air·(Wtarget−Win); ṁair≈ρ·Q.
5,000 CFM at 1.20 kg/m³ with humidity ratio rising from 0.004 to 0.008 kg/kg requires about 40.8 kg/h of added moisture.
HVAC engineering calculator · Updated Sep 17, 2026
Humidification Load Calculator — Airflow, Humidity Ratio & kg/h
Size first-pass humidification moisture capacity from airflow and entering/target humidity ratio, with kg/h, lb/h and water L/h outputs.
Inputs
Live result
Humidity-ratio rise 0.004 kg/kg
Dry-air flow approximation 2.8316847 kg/s
Base moisture addition 40.77626 kg/h
Design capacity with allowance 44.853886 kg/h
Design capacity 98.885891 lb/h
Approximate liquid-water equivalent 44.853886 L/h
Assumptions & limits
- Air density is user-entered rather than silently fixed.
- This is the airstream moisture load; infiltration, envelope leakage, process moisture and distribution losses may require separate allowance.
Frequently asked questions
What does this Humidification Load Calculator calculate?
Size first-pass humidification moisture capacity from airflow and entering/target humidity ratio, with kg/h, lb/h and water L/h outputs.
Why are the assumptions shown?
HVAC results depend on air properties, measured conditions and design conventions. MAXScanner exposes the governing assumptions so the result can be checked instead of hiding them behind a single number.
Can this replace final HVAC design?
No. Use it for transparent sizing and cross-checking, then verify final selections against measured conditions, equipment data and applicable design standards.