Cooling Load Estimation for Commercial Buildings
Cooling Load by Building Type
| Building Type | BTU/sq ft (Cooling) | Key Load Factors |
|---|---|---|
| Office (standard) | 30–40 | Computers, lighting, occupancy |
| Office (data-heavy) | 40–60 | Servers, workstations, UPS |
| Retail store | 20–30 | Display lighting, door openings |
| Restaurant | 35–50 | Kitchen equipment, high occupancy |
| Hospital | 40–60 | Medical equipment, ventilation |
| Warehouse | 8–15 | Minimal, mainly roof load |
| Server room | 60–120 | Extreme equipment density |
Frequently Asked Questions
How do you estimate cooling load for a commercial building?
Use ASHRAE Manual N or the CLTD method. For quick estimation: offices need 30–40 BTU/sq ft, retail 20–30, restaurants 35–50, server rooms 60–120 BTU/sq ft. Add internal loads for equipment and occupancy.
What is the cooling load per person?
Each person adds approximately 400 BTU/h sensible heat (body temperature) and 200 BTU/h latent heat (moisture), for a total of 600 BTU/h. In a conference room with 20 people, that's 12,000 BTU/h just from occupancy.
How do internal loads affect cooling?
Internal loads (people, equipment, lighting) add heat that the AC must remove. A typical office with 50 people and 50 computers adds 50,000+ BTU/h of internal heat. This is why commercial buildings need more BTU/sq ft than residential.
Disclaimer: For preliminary design only. Verify against local codes and professional engineering requirements.