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What size generator do you need for an RV air conditioner?
Updated
Using the typical figure in our calculator, a 13,500 BTU RV air conditioner needs about 1,500 running watts and 3,000 starting watts. With headroom, look for at least 1,900 running watts, and make sure the starting number is covered. A generator sold as "2,000 watts" will not start it.
The math, with and without the microwave
- Air conditioner alone3,000 starting watts
- Air conditioner and microwave4,000 starting watts
| What you run | Running watts | Starting watts | Look for at least |
|---|---|---|---|
| 13,500 BTU RV air conditioner | 1,500 | 3,000 | 1,900 running |
| Air conditioner and microwave | 2,500 | 4,000 | 3,150 running |
The second row is the one that catches people. The air conditioner runs fine, then someone heats up lunch and the generator trips. Add your own mix in the wattage calculator. A 15,000 BTU unit needs more than the figures above, so check its label.
Which picks fit
- The Champion 4000-Watt Dual Fuel has 3,000 running and 4,000 starting watts on gas, a TT-30R RV outlet and a CO shutoff, at about 52 pounds. It covers the air conditioner. With the microwave on too, 2,500 running watts fits under 3,000 on gas but leaves little room. The caveat: on propane it drops to 2,700 running watts, and the listing we read gave no propane starting figure.
- The Westinghouse iGen5000DF has 3,900 running and 5,000 peak watts and a TT-30R outlet. Owners with RVs say it handles a 15,000 BTU air conditioner. The caveat: it weighs about 105 pounds, so it rides in the truck bed, not the storage bay.
- The WEN 56235i does not fit this job. Its 2,350 surge watts is under the 3,000 needed to start the air conditioner, and it has no 30 amp RV outlet.
All five are compared on the roundup page.
Noise rules at the campground
In national parks, federal rule 36 CFR 2.12 bans running a generator above 60 decibels, measured on the A-weighted scale at 50 feet. Many other campgrounds set their own limits and quiet hours. Maker noise numbers are claims, and they use different distances. Champion claims 64 dBA from 23 feet. Westinghouse claims "as low as 52 dBA" for the iGen5000DF and does not give a distance in the part we read. Neither number tells you what a ranger's meter will read at 50 feet with the air conditioner running, because an inverter gets louder as the load goes up. More on this in inverter vs open frame.
RV safety
The 20 foot rule applies to campers too. Set the generator well away from your RV and your neighbor's, with the exhaust pointed away from windows, vents and tents. Never run it in a storage bay, under a slide-out or inside a toy hauler garage. Keep a working battery CO alarm inside the RV.
Safety first, every time
- Carbon monoxide kills. Never run a generator indoors, in a garage, in a shed or on a porch, even with the door open. Keep it at least 20 feet from the house. Point the exhaust away from windows, doors and vents. Put battery CO alarms inside your home.
- Never backfeed. Do not plug a generator into a wall outlet or dryer outlet. It can kill a utility worker or a neighbor and can start a fire. To power home circuits you need a transfer switch or an interlock kit, installed by a licensed electrician.
- Without that, run heavy-duty outdoor extension cords from the generator straight to each appliance.
- Let the engine cool before you refuel. Store fuel outside the house.