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What size generator to run a Air compressor (1 HP)?

Typical draw: 1500W running / 3000W starting. One of the toughest small-shop starting loads.

SIZING PLATE1 LOADS · +25% HEADROOM
Total running watts
1,500 W
Peak (largest start)
3,000 W
Buy at least
1,900 W rated
Look for ~1,900W running / 3,000W surge or better.

Right size: Mid-size inverter (3,500W / 4,000W surge)

Typical price $600-1,400 · e.g. Champion 4250 open-frame inverter, Westinghouse iGen4500, Generac GP3500iO

RV 13,500 BTU AC (especially with soft-start), fridge + window AC, storm essentials for smaller homes. The sweet spot of quiet, portability, and real capacity for most first-time buyers.

See current prices on Amazon

One size up: Mid-size portable (6,500W / 8,100W surge)

Typical price $700-1,200 · e.g. Westinghouse WGen6500, Champion 6250, Generac GP6500

Storm essentials with margin: fridge, freezer, sump pump, furnace fan, well pump (240V models), lights and electronics together. Louder open-frame design; electronics prefer models with THD under 5% or an inverter.

See current prices on Amazon

Add more appliances

Real outages aren't one appliance. Adjust the full load below — your Air compressor (1 HP) is pre-checked.

SIZING PLATE1 LOAD · +25% HEADROOM
Total running watts
1,500 W
Peak (largest start)
3,000 W
Buy at least
1,900 W rated
Look for ~1,900W running / 3,000W surge or better.

Peak assumes your largest motor starts while everything else runs — the honest worst case. Start big motors one at a time and a smaller unit may cope, but this number won't let you down.

Kitchen
Heating & cooling
Pumps & well
Electronics
Medical & safety
Lighting
Laundry
Household
Tools & outdoor
RV & camping

Generators that fit

Right size: Mid-size inverter (3,500W / 4,000W surge)

Typical price $600-1,400 · e.g. Champion 4250 open-frame inverter, Westinghouse iGen4500, Generac GP3500iO

RV 13,500 BTU AC (especially with soft-start), fridge + window AC, storm essentials for smaller homes. The sweet spot of quiet, portability, and real capacity for most first-time buyers.

See current prices on Amazon

One size up: Mid-size portable (6,500W / 8,100W surge)

Typical price $700-1,200 · e.g. Westinghouse WGen6500, Champion 6250, Generac GP6500

Storm essentials with margin: fridge, freezer, sump pump, furnace fan, well pump (240V models), lights and electronics together. Louder open-frame design; electronics prefer models with THD under 5% or an inverter.

See current prices on Amazon
This site earns commissions from qualifying purchases made through links to Amazon and other retailers, at no extra cost to you. Wattage figures are typical estimates — actual draw varies by model. Always verify against your appliance's nameplate, and consult a licensed electrician for any panel or hardwired connections.