What Size Generator Runs an RV Air Conditioner? (BTU Chart)

Last verified 2026-08-28 · every wattage cites its source · methodology

The RV air conditioner is the load that decides this: with no mitigation you're sizing to ~6,600W, with load-shedding at compressor start ~5,800W, and with a soft-start kit ~5,700W — the popular 3,400–4,500W RV inverter class only works with mitigation, not on the naive worksheet.

The list, with sourced watts

Appliance	Running watts	Starting (surge)
RV air conditioner (10,000 BTU class)	1,500	1,100
RV air conditioner (13,500 BTU)	1,800	2,800
RV air conditioner (15,000 BTU)	2,000	3,500
RV refrigerator	180	600
RV power converter/charger (45A class)	800	—
Microwave oven (1000 W cook power)	1,000	2,000

No mitigation (everything may start at once) — peak 5,480W

the default worksheet method — the most conservative answer

Peak demand: 5,480W · unit must also sustain 3,980W running (+10–20%)

Westinghouse WGen5300
5,300W rated · 6,600W starting · gasoline
Spec: manufacturer

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Honda EU7000iS
5,500W rated · 7,000W starting · gasoline (EFI) · inverter
Spec: authorized_dealer

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Load-shed at compressor start — peak 3,500W

switch other loads off while the AC compressor starts, then run them together — needs discipline or an EMS. The unit must still sustain the whole kit running.

Peak demand: 3,500W · unit must also sustain 3,980W running (+10–20%)

Westinghouse WGen5300
5,300W rated · 6,600W starting · gasoline
Spec: manufacturer

As an Amazon Associate, needwatts.com earns from qualifying purchases. Links below are affiliate links — this never affects our wattage math or which units we list.

See Westinghouse WGen5300 on Amazon →

Honda EU7000iS
5,500W rated · 7,000W starting · gasoline (EFI) · inverter
Spec: authorized_dealer

As an Amazon Associate, needwatts.com earns from qualifying purchases. Links below are affiliate links — this never affects our wattage math or which units we list.

See Honda EU7000iS on Amazon →

Soft-start kit installed — peak 4,730W

a soft-start kit "can cut surge ~50%+" (etrailer's claim; kit-dependent)

Peak demand: 4,730W · unit must also sustain 3,980W running (+10–20%)

Westinghouse WGen5300
5,300W rated · 6,600W starting · gasoline
Spec: manufacturer

As an Amazon Associate, needwatts.com earns from qualifying purchases. Links below are affiliate links — this never affects our wattage math or which units we list.

See Westinghouse WGen5300 on Amazon →

Honda EU7000iS
5,500W rated · 7,000W starting · gasoline (EFI) · inverter
Spec: authorized_dealer

As an Amazon Associate, needwatts.com earns from qualifying purchases. Links below are affiliate links — this never affects our wattage math or which units we list.

See Honda EU7000iS on Amazon →

Data note: rv_ac_10000btu starting range is derived from two qualitative claims (no exact published class start figure) — provisional; corroborate against the specific unit's LRA before printing point data.

Adjust this list in the calculator →

What size generator do I need for an RV air conditioner?

Naive worksheet: ~6,600W. With load-shedding at compressor start or a soft-start kit, a smaller class covers the same rig — see the three tiers above.

Do soft-start kits really work?

Per etrailer (cited on our RV rows), a soft-start kit can cut the compressor's start surge roughly in half — kit-dependent, so treat the halved figure as an estimate and confirm against your kit's spec.

Why do starting watts matter?

The AC compressor briefly draws far more than its running watts. The generator must cover everything running plus that single start surge — or shed load while it starts.

Sources

UDPOWER RV AC wattage guide (BTU-class table) (vendor)
KME Vehicle AC Store - RV AC amps by BTU size (vendor)
RV With Tito - RV AC power use (vendor)
etrailer 'What Size Generator to Run an RV Air Conditioner' (vendor)
Grounded Electric generator wattage chart (licensed-electrician authored) (vendor)
OptingOutofNormal.com RV Appliance Power Consumption chart (PDF) (vendor)
Progressive Dynamics PD9245C product specifications (manufacturer)
Wattage Worksheet '3R0WATTGUIDE' (generator reference guide, Home Depot-hosted PDF) (vendor)
A-iPower Wattage Chart (Sam's Club-hosted PDF) (vendor)
Champion Power Equipment 'Choosing a Generator' wattage flyer (manufacturer)

Figures are conservative sizing values chosen from the range these sources report. Your appliance's nameplate is authoritative.