Add the wattage of appliances that must operate during an outage, then allow for power factor and headroom.
Minimum indicative inverter rating
1,016 VA
Consider the next standard size above 1,016 VA, after checking surge loads.
Motor and compressor starting surges may require a larger inverter.
Verify continuous and surge ratings with the manufacturer.
Required VA = load watts × safety factor ÷ power factor.
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