Heat load calculator
How much CRAC capacity does your room actually need?
Enter your room dimensions, IT racks, occupants and envelope class. We compute total sensible heat load, kW/m² density, and recommended installed CRAC capacity with N+1 / 2N redundancy headroom.
Step 1 · Room class
Step 2 · Room dimensions & load
Net usable floor area of the IT room
Total IT racks (excluding empty)
Diversified average. >15 kW triggers high-density
Maximum simultaneous occupants
Average IT load as % of nameplate. 0.95 is conservative for production data halls.
N = base, N+1 = one spare, 2N = fully duplicated
Result
Sensible heat load
42.5 kW
0.71 kW/m² density
Installed CRAC capacity (N+1)
59.5 kW
Includes 20% headroom + redundancy multiplier
Recommended topology
DX (perimeter or in-row)
Load decomposition
IT equipment
40.00 kW
94%
Envelope gain
1.80 kW
4%
Lighting
0.60 kW
1%
Occupants
0.20 kW
0%
Infiltration
2.02 kW
5%
Our engineers turn this into a full bill of materials, redundancy schematic and commissioning plan within one business day.
Methodology
How the calculation works
1. IT load. Rack count × diversified kW per rack. We multiply by a diversity factor (default 0.95) to reflect that not every rack runs at nameplate simultaneously. Production data halls average 0.85-0.95; lab and dev environments lower.
2. Lighting. 10 W/m² for modern LED lighting. Older fluorescent fits-out can run 18-22 W/m².
3. Occupants. 100W sensible per person at peak. Sustained occupant load is rare in mature data centres but spikes during maintenance windows.
4. Envelope gain. 20-50 W/m² depending on room class. Office conversions with external windows are at the high end; purpose-built insulated halls are at the low end.
5. Infiltration. 5% of the subtotal, representing door-cycling air ingress, cable-penetration leakage, and unsealed raised-floor returns.
6. Redundancy headroom. N+1 multiplier ~1.4×, 2N multiplier 2.4×. Includes a base 20% headroom for diversity, growth and commissioning margin even at N.
This calculator returns sensible heat load only. Latent load (humidity control) varies regionally — Brisbane and tropical sites need explicit dehumidification sizing on top of the sensible kW. For deployments above 50 kW IT load we recommend a CFD-modelled load assessment.