Portable Generator Sizing for Home Outages
Start with the loads you truly need to keep running, then account for startup surge.
A generator should be sized from essential loads rather than the square footage of the house. Refrigeration, sump pumps, furnaces, well pumps and some tools can draw substantially more power for a moment when motors start.
List the essentials first
Write down the running wattage of the appliances and systems you want at the same time. Then identify motor-driven equipment with higher starting requirements.
Fuel choice changes ownership
Gasoline is widely available; propane stores differently and dual-fuel machines add flexibility. Consider what fuel you can safely store and realistically obtain during an outage.
Connection method is a safety decision
Never improvise a connection to household wiring. Transfer equipment and home electrical connections should follow manufacturer instructions and applicable electrical requirements; use a qualified electrician when required.
Portable generators stay outside
Engine-driven portable generators produce carbon monoxide. Operate them outdoors and follow the manufacturer's placement and ventilation instructions.
A strong benchmark to compare
Westinghouse WGen9500DFc
A current dual-fuel example rated by Westinghouse at 9,500 running watts on gasoline / 8,500 on propane, with 12,500 / 11,200 peak watts respectively. It's also marketed as transfer-switch ready.
Never run a portable generator indoors
Generator sizing comes after safe placement and connection planning. Before purchasing, confirm safe outdoor placement and a compliant home connection method with a qualified electrician.
Research shortlist, not HH Tested. Always follow manufacturer safety instructions and local electrical requirements.
Our buying rule
Start with the problem and the constraints, then buy the simplest product that solves them reliably. Bigger, more powerful or more expensive is not automatically better.
Shop for the right fit
Use the buying criteria above to compare current listings and manufacturer specifications. Prices and availability can change.
Compare on Amazon (paid link)Last updated September 2026. Product specifications and retailer availability can change; verify current manufacturer specifications before purchase.
See our full portable-generator comparison →