HVAC Volume Load Calculator calculates heating and cooling loads based on room volume. Enter floor area, ceiling height, occupancy, and insulation values to estimate HVAC requirements using W/m³ or BTU/h·ft³ units.
About watts per cubic meter (W/m³). In this calculator, heating and cooling intensities are expressed relative to room volume. W/m³ indicates how much power is required for each cubic meter of space, which is especially useful for tall rooms or industrial spaces where ceiling height significantly affects thermal loads.
About kilowatts (kW). As in area-based calculations, kilowatts are used for larger loads. One kilowatt equals 1,000 watts. Converting a volume-based load into total kW helps you size equipment such as boilers, heat pumps, or cooling units.
About BTU/h·ft³. In Imperial units, load intensity is often expressed as BTU/h per cubic foot. This reflects how much energy is needed to heat or cool a given volume of air. It allows designers in the US and other Imperial-system regions to quickly evaluate requirements based on familiar standards.
Calculation. Heating and cooling loads are estimated using the space volume (area × height), intensity factors, and internal gains.
Volume = Floor Area × Ceiling Height
Cooling Load = (Cooling Intensity × Volume) + (Internal Gains × Area) + (Occupants × 75 W)
Heating Load = (Heating Intensity × Volume)
- Example 1: A 120 m² room with 2.7 m ceiling height = 324 m³ volume. At 40 W/m³ cooling intensity and 12 W/m² internal gains, with 4 people → ≈15.3 kW cooling load.
- Example 2: The same room with 25 W/m³ heating intensity → ≈8.1 kW heating load.
- Example 3: A heating load of 25,000 BTU/h = 25,000 ÷ 3,412 ≈ 7.33 kW.
Corresponding tools. For area-based HVAC load calculations without ceiling height, use the HVAC Load Calculator. You can also explore other HVAC and MEP tools such as duct sizing, CFM calculation, and voltage drop calculators.
