# HVAC Load Calculator

> HVAC Load: Sensible kW = ρ × Q × cp × ΔT. Methodology stated, your own inputs only.

Page: https://freecalculator.tech/tools/hvac-load-calculator
Last reviewed: 2026-10-20

## Formula

Sensible kW = ρ × Q × cp × ΔT. Latent kW = ρ × Q × hfg × Δw. Total = sensible + latent.

- 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).

## Inputs

- 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

2 m³/s, density 1.2, 10 K difference, humidity ratio difference 0.004.
1. Sensible = 2 × 1.2 × 1.006 × 10 = 24.144 kW.
2. Latent = 2 × 1.2 × 2,501 × 0.004 = 24.010 kW.
3. Total = 48.154 kW.

## 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.

## 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.

## Sources

- ASHRAE — https://www.ashrae.org/technical-resources/ashrae-handbook

## Cite this page

- APA: Free Calculator. (2026, October 20). HVAC Load Calculator. https://freecalculator.tech/tools/hvac-load-calculator
- MLA: "HVAC Load Calculator." Free Calculator, 20 Oct. 2026, https://freecalculator.tech/tools/hvac-load-calculator.
- Link: HVAC Load Calculator — Free Calculator, https://freecalculator.tech/tools/hvac-load-calculator