What size generator do I need?
Plain-English guides to working out how many watts you need.
What size generator do I need for 200 amp service?A 200 amp panel is rated for 48,000 W, but that's not your load. Most homes back up essentials with 5,000–10,000 W. How to size to what you run.
What size generator do I need for a 30 amp RV?A 30 amp RV can draw 3,600 W at most. That's a ceiling, not a size. One 13,500 BTU AC plus basics needs about 2,200 running and 4,000 starting W.
What size generator do I need for a 50 amp RV?A 50 amp RV can draw up to 12,000 W, but two 13,500 BTU ACs plus the basics need about 5,700 running and 7,500 starting watts. Sizes for 1, 2 or 3 ACs.
What size generator do I need for an electric water heater?An electric water heater uses 3,000–4,500 W at 240 V. Plan on 5,500+ running watts, a 240 V outlet and a transfer switch. Sizes explained.
What size generator do I need to run a gas furnace?A gas furnace only needs power for its blower and controls: about 700 running and 1,800 starting watts. Why an inverter is the safer pick.
What size generator do I need to run a microwave?A microwave draws more than its cooking watts: a 1,000 W model can pull 1,500–2,000 W. Most need a 2,000–3,500 W generator. How to read the label.
What size generator do I need to run a refrigerator and freezer?A fridge and freezer together need about 700 running and 1,500 starting watts. A 2,000 W generator usually covers both. Older units need more.
What size generator do I need for a space heater?A space heater uses up to 1,500 W on high, with no start-up surge. One heater needs 1,800+ running watts; two need 3,600+. Sizes, run time and tips.
What size generator do I need for a sump pump?A 1/2 HP sump pump needs about 1,000 running and 2,150 starting watts. Add a fridge and you need about 3,000–3,500 W. Here's the math.
What size generator do I need for a travel trailer?Most travel trailers need 2,000 W without AC, or about 3,000–4,500 W to run one roof AC. Sizes by AC, trailer length and what you plug in.
What size generator do I need for a well pump?A 1/2 HP well pump runs on about 1,000 W but needs a 2–3 kW generator to start. Most are 240 V. Sizes by HP, and how to hook it up safely.
What size generator do I need for a window AC?Window AC watts by BTU, from 5,000 to 12,000. An 8,000 BTU unit needs about 750 running and up to 2,000 starting watts. Sizes and a table.
What size generator do I need?Add up running watts, then add the one biggest start-up surge. Most homes need 3,000–4,500 W for the essentials. Here's the simple math.
What size generator do I need to run a house?Essentials need about 3,000–4,500 W. Add a well pump or window AC and it's 5,000–7,500 W; central air needs 7,500–10,000 W. Sizes by home, with the math.