HVAC Load Calculator
HVAC Load: Sensible kW = ρ × Q × cp × ΔT. Methodology stated, your own inputs only.
In short
HVAC Load: Sensible kW = ρ × Q × cp × ΔT. Methodology stated, your own inputs only.
Formula: Sensible kW = ρ × Q × cp × ΔT. Latent kW = ρ × Q × hfg × Δw. Total = sensible + latent.
What this calculator does
HVAC Load: Sensible kW = ρ × Q × cp × ΔT. Methodology stated, your own inputs only. Worked example, questions and limitations included.
Use it to turn Airflow, Air density at your conditions (≈1.2 near sea level — enter yours), Dry-bulb temperature difference, Humidity ratio difference (blank = sensible only) into a checked result you can compare, copy, or rerun with different assumptions.
The page shows the formula, a numeric worked example, and the assumptions that affect this facilities calculation.
Inputs and what they mean
- Airflow
- — number value.
- Air density at your conditions (≈1.2 near sea level — enter yours)
- — number value.
- Dry-bulb temperature difference
- — number value.
- Humidity ratio difference (blank = sensible only)
- — number value.
How to use it
- Enter each value in the unit shown next to the box (use the unit converter first if your numbers are in other units).
- Check the breakdown to see every intermediate step.
- Read the limitations before relying on the result.
Formula
Methodology: air-side psychrometric load from ASHRAE Handbook — Fundamentals, with cp = 1.006 kJ/kg·K and hfg = 2,501 kJ/kg.
This is the load carried by an airstream, not a full room load calculation (no solar, occupancy or envelope).
Links: Cooling Load, Heating Load and BTU pages cover room-based estimates.
Sensible kW = ρ × Q × cp × ΔT. Latent kW = ρ × Q × hfg × Δw. Total = sensible + latent.
Inputs used: Airflow, Air density at your conditions (≈1.2 near sea level — enter yours), Dry-bulb temperature difference, Humidity ratio difference (blank = sensible only).
Worked example
Ventilation air
- Sensible = 2 × 1.2 × 1.006 × 10 = 24.144 kW.
- Latent = 2 × 1.2 × 2,501 × 0.004 = 24.010 kW.
- Total = 48.154 kW.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Limitations and assumptions
- Air-side only; not a design load calculation.
- Constant properties assumed across the coil.
- Results are estimates built only from the figures you enter. No electricity, fuel or gas price, equipment efficiency or benchmark is built in — tariffs vary by supplier, region and time, and equipment data must come from the manufacturer. Designs and installations must be checked by a qualified professional.
- The result depends on the values you enter for this hvac load calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.
Reference: ASHRAE
Last reviewed:
Common questions
Where does the humidity ratio come from?
A psychrometric chart or calculator for your entering and leaving air conditions. Check the formula, example, and limitations on this page before using the result for a real facilities decision.
Is this a room load calculation?
No. It is the heat an airstream carries. Full room loads need solar, envelope, people and equipment gains.
Why enter air density?
It changes with altitude and temperature; the 1.2 figure is only near sea level. Check the formula, example, and limitations on this page before using the result for a real facilities decision.
How do I use the HVAC Load Calculator?
Enter the required values for Airflow, Air density at your conditions (≈1.2 near sea level — enter yours), Dry-bulb temperature difference, Humidity ratio difference (blank = sensible only). The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.
What formula does the HVAC Load Calculator use?
Sensible kW = ρ × Q × cp × ΔT. Latent kW = ρ × Q × hfg × Δw. Total = sensible + latent. The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone.
Can the HVAC Load Calculator be used for exact decisions?
Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.
Sources
Method based on ASHRAE.
Cite this page
Free Calculator. (2026, October 20). HVAC Load Calculator. https://freecalculator.tech/tools/hvac-load-calculator
"HVAC Load Calculator." Free Calculator, 20 Oct. 2026, https://freecalculator.tech/tools/hvac-load-calculator.
HVAC Load Calculator — Free Calculator, https://freecalculator.tech/tools/hvac-load-calculator
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