HVAC Airflow & BTU Load Calculator

Inputs

Airflow (Q)

Supply, return or ventilation airflow through the coil or heat exchanger.

m³/h

Temperature difference (ΔT)

Air temperature rise for heating or drop across a cooling coil. Use the absolute difference.

°C

Target sensible load (q_t)

Target sensible capacity used to back-calculate required airflow and ΔT.

Air density (ρ)

Air density at the coil or duct condition. Room-temperature sea-level air is about 1.2 kg/m³.

kg/m³

Specific heat (cₚ)

Specific heat of air. Dry air near room temperature is about 1.006 kJ/(kg·K).

kJ/kg·K

Default result

Sensible load(q)

3.353kW

Pass

sensible-only capacity from airflow and temperature difference

Also computed

Airflow for target load(Q_req)1,342m³/h

ΔT for target load(ΔT_req)16.57°C

Cooling tons equivalent(tons)0.9535tons

Airflow per ton(CFM/ton)555.6cfm/ton

high airflow per ton; check coil leaving-air temperature and noise

Air mass flow(ṁ)0.3kg/s

Method notes 3 notes

Sensible heat only: q = ρ · cₚ · Q · ΔT. It does not include latent/moisture load.
With standard air, the same relation is the common imperial shortcut q ≈ 1.08 × CFM × Δ°F.
Use Manual J/ASHRAE load methods, equipment data and psychrometrics for final HVAC equipment sizing.