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Power Prepared guide

How Much Backup Power Does a House Need?

Estimate backup needs from watts, watt-hours, essential loads and desired runtime.

Editorial standard: Seller performance claims are treated as claims unless independently substantiated. Electrical and high-speed rotating equipment can be hazardous.

Step 1: list essential loads

Record each device's running watts and expected hours of use.

Step 2: calculate energy

Multiply watts by hours to estimate watt-hours. Add margin for conversion losses and uncertainty.

Step 3: check peak power

Make sure the inverter or generator can handle simultaneous loads and startup surges. Whole-home loads can be dramatically larger than an essentials-only plan.

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