What Is a Whole-House vs. Partial-House Backup?

Whole-house backup means every circuit in your home stays powered during an outage, requiring a larger generator (typically 22 kW or more) sized to handle your home's full simultaneous electrical load. Partial-house (or "essential circuits") backup powers only a selected subset — refrigerator, well pump, some lighting, one AC zone — using a smaller, less expensive generator (commonly 10–14 kW) and a load-management or circuit-selection setup at the transfer switch. Most residential installations fall somewhere between these extremes, tailored to which circuits actually matter to the homeowner.