Backup generator size calculator

Work out roughly how many watts of backup generator you need based on your home size and how much you want to keep running during an outage.

Recommended generator size

12,000 watts

This is an estimate of continuous watts needed; an electrician will size the exact generator based on your appliances and HVAC.

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Actual sizing depends on your specific appliances, HVAC tonnage, and starting wattage, confirmed by a load calculation.

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Your calculator details and estimate are included with your inquiry so electricians can bid on your specific job. Just add your area, timeline, and contact info.

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Enquiries submitted through our contact forms may be passed to partner providers who can do the work, and we may receive a referral fee. Our rankings are based solely on our published scoring method and are never influenced by referral fees.

Get quotes from generator installation electricians

Ranked by our published rubric from recent Google reviews, weighted by relevance to this service (the same order as the category page).

Super Fast Electric
4.9(668) 93
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American Air, Plumbing, and Electrical
4.9(9949) 93
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JCD Electric
5.0(145) 92
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All Electric Services
4.9(1568) 89
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Quantum Force Electric LLC
5.0(145) 88
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