How to size a UPS for a server room

Sizing a UPS for a server room comes down to load, runtime and redundancy. Get these right and the rest follows.

Total the load

Add up the wattage of everything the UPS will protect — servers, storage, switches. Use watts, not just VA, and leave 20–30% headroom for growth and inrush.

Plan the runtime

Decide whether you need minutes for a clean shutdown or longer autonomy to ride through outages or reach a generator. Battery cabinets extend runtime.

Redundancy

For high availability, use a modular or parallel system (N+1) so a module can fail or be serviced without dropping the load.

For mid rooms look at the Powerware 9150; for larger loads the 9330. Need a hand? Ask for a free sizing consultation.