What Size Whole House Generator Do I Need?

The useful answer comes from the home's electrical loads and your backup priorities—not from square footage alone.

Start with what you want to run

Some homeowners want essential circuits. Others want central air conditioning, water heating, cooking and most normal household loads. Those choices change the required capacity.

Large loads matter

Central HVAC equipment, pumps, electric water heaters, ranges, dryers and other high-demand equipment can shape generator sizing. Motor starting demand can also be higher than normal running demand.

Load management can change the design

A load-management system can prioritize or temporarily shed selected loads so the generator does not have to support every large appliance at the same instant.

Learn how load management works →

Why square-foot rules are incomplete

Two homes of similar size can have very different electrical equipment. A load assessment and the actual equipment specifications provide a more defensible basis for system design.