Office cooling-load estimate
Use this free cooling load calculator for an early estimate of an office room cooling requirement. The Area Load Method combines an entered sensible allowance per floor area with occupant sensible and latent heat, plus optional fresh-air load. It is not a detailed hourly building simulation. Calculate without an account and compare the component totals before using a result in an equipment discussion or a draft schedule.
Inputs and the actual formula
Enter room length, width, ceiling height, room type, occupancy, area load allowance, indoor temperature and outdoor conditions. Area sensible load equals length × width × allowance in W/m². Total sensible load adds occupant sensible heat and optional fresh-air sensible heat; total latent load adds occupant latent heat and optional fresh-air latent heat. The selected Office profile uses 75 W sensible and 55 W latent per person.
Worked example: assumed 40 m² office
Assume length 8 m, width 5 m, ceiling height 2.8 m, Office occupancy of five people, and an area allowance of 100 W/m². Assume outdoor dry-bulb temperature 33°C, outdoor relative humidity 55%, indoor dry-bulb temperature 24°C and desired indoor relative humidity 55%. These are illustrative assumptions, not prescribed Singapore design conditions. Turn fresh air off for this reproducible Area Load Method example.
Reproducing the displayed answer
The assumed area is 40 m² and volume is 112 m³. Area sensible heat is 4,000 W; five assumed occupants add 375 W sensible and 275 W latent. The result is 4,650 W, or 4.65 kW. With the engine’s fixed supply temperature of 13°C, air density of 1.204 kg/m³ and specific heat of 1,005 J/(kg·K), the sensible supply airflow is approximately 328.69 L/s.
Humidity and ventilation limitations
The requested 55% indoor humidity is a design assumption for this example, not an editable Area Load Method input. The current engine fixes room relative humidity at 50% when computing optional fresh-air enthalpy. With fresh air disabled, outdoor conditions and room humidity do not alter the 4.65 kW result. Do not use that result as the complete ventilated-office duty. Reassess ventilation, envelope, solar gains, lighting and equipment before selecting equipment.
Singapore project review
Treat this output as a draft for review, not a stamped design or an approval. For a Singapore submission, check the applicable SS553 requirements and the project specification with the responsible designer. Verify the input schedule, record the assumptions, and reconcile the calculation with drawings and manufacturer data. This tool does not identify every applicable requirement, certify compliance, or replace professional judgement about installation, operation, safety, and maintenance. Retain the calculation date and revision so later changes can be traced to their original assumptions.