Battery System or Standby Generator?
The right choice depends on how long your outages last and what you need to power. Battery systems switch instantly and run silently - they handle short outages and cover sensitive electronics without interruption. Standby generators burn LP or natural gas and run indefinitely, making them the better option for multi-day outages or heavy loads like central AC and well pumps. Many homeowners use both: a battery system for automatic coverage and a generator for extended events.
Sizing for Your Home
Start with your critical loads. A refrigerator draws 100-200W, a sump pump 750-1,500W, a window AC unit 500-1,500W, and a central AC system 3,000-5,000W. Add up what you want to run at the same time, then add 20% for startup surges. For battery systems, multiply watts by hours to get the watt-hours of capacity you need. For generator sizing, match peak wattage of your largest motor loads.
Transfer Switch: What You Need
Every whole-home backup system requires a transfer switch or interlock to safely connect to your panel. Standby generators include an automatic transfer switch. Portable generators require one installed by a licensed electrician. Some battery systems - like the EcoFlow DELTA Pro Ultra with Smart Home Panel 2 - include their own circuit-level management that does not require a full panel replacement. Budget for professional installation when purchasing a standby generator or panel-connected battery system.
240V and Split-Phase Output
Standard US homes run on 240V split-phase power for high-draw appliances - electric dryers, water heaters, central AC, and EV chargers. Not all generators and battery systems support 240V. If you need to run 240V appliances during an outage, verify the unit explicitly offers split-phase 240V output. The Anker SOLIX F3800, EcoFlow DELTA Pro Ultra, and Cummins RS-series standby generators all provide true 240V split-phase output.
