How Much Backup Power Does a House Need?

Estimate critical loads and runtime before deciding how large a backup system should be.

Start with requirements

Backup planning starts with outage scenarios. A short outage for a refrigerator and communications is a different design problem from running heating, cooling or an entire home for days.

Think in systems

Compare options by critical loads, startup surge, runtime, charging or fuel availability, installation, maintenance, noise, ventilation and safe operating location.

Questions worth answering

• What exact loads need power, and for how long?
• What peak or startup demand must equipment handle?
• What installation, ventilation, protection or code constraints apply?
• What happens when expected generation, charging or fuel is unavailable?
• Which assumptions can you measure before spending money?