This depends on your load and the type of equipment that you have connected to the UPS. For example, if you have 3000W of load drawn by your equipment, it is advised choose a slightly larger UPS unit 5kVA or 6kVA. This way you will have coverage for incoming surges and/or heavy machinery drawing larger load when they first start up. If you don’t know your current load give our friendly team a call to scope up the right size UPS for you.