Generator sizing Last reviewed June 2026

What Size Generator for an RV? A Complete Guide

By the WhatSize editorial team 5 min read Standards-reviewed

TL;DR

A small RV (class B/camper) needs a 2,000-2,500W generator. A medium RV (class C/travel trailer) needs 3,000-3,500W. A large RV (class A/fifth wheel) with 2 AC units needs 5,000-7,500W.

Looking for a different size? See What Size Generator for a 2,000 Sq Ft House? or browse all generator sizing guides.

RV Generator Sizing: AC is Everything

When sizing an RV generator, your single biggest load is the air conditioner. A 13,500 BTU RV AC unit draws about 1,600W running but needs 2,500-3,000W to start. If you have two AC units (common in large fifth wheels and class A motorhomes), you could need 5,000W or more for starting surge alone.

After AC, the next biggest loads are the microwave (1,000W), water heater (1,200W if electric), and converter/battery charger (500-1,000W). The good news is you probably won't run all of these at the same time — and your RV's power management system may help you prioritize loads.

For most RV owners, a 3,500W generator is the sweet spot. It can handle one AC unit, the microwave, refrigerator, lights, and devices without constant load management.

Top picks for this size

BEST OVERALL

Westinghouse 5000W Dual Fuel Inverter #ad

5000W, Dual Fuel, Remote Start, Super Quiet

★★★★☆ 4.7 · 19.3K+ ratings

Dual Fuel (Gas/Propane)Remote Electric StartRV Ready

$949 approx

Check price

BUDGET

Champion 2500-Watt Dual Fuel Inverter #ad

★★★★ 4 · 136+ · $549

Amazon

These Amazon-available picks meet the calculated spec. For region-specific or licensed contractor-installed options, consult a local professional. See our Disclaimers.

RV Generator Options by RV Type

Small camper / pop-up / teardrop (no AC or small 5,000 BTU): 1,500-2,000W inverter generator — Honda EU2200i or similar
Class B van / small travel trailer (1 AC unit, 13,500 BTU): 3,000-3,500W — Westinghouse 3,500W or dual Honda EU2200i in parallel
Class C / large travel trailer (1 AC + microwave + converter): 3,500-4,500W — Champion 4,500W
Class A / fifth wheel (2 AC units, full kitchen, washer/dryer): 5,000-7,500W — Generac or Cummins Onan built-in

Frequently asked questions

What size generator do I need for an RV?

A 13,500 BTU RV AC needs about 2,500-3,000W to start, so a single 2,000W generator won't be enough. However, some Honda generators can be paired in parallel to deliver 4,000W total. Alternatively, consider a soft start kit for the AC unit to reduce starting surge.

Is it better to get a built-in RV generator or portable?

Built-in generators (like Onan) run on the RV's propane/diesel and are permanently installed — convenient but expensive ($3,000-5,000). Portable generators ($500-1,200) are cheaper and can be used elsewhere, but require manual setup, fueling, and security measures.

How much fuel does an RV generator use?

A 3,500W portable generator at 50% load uses about 0.5-0.6 gallons per hour. At full load (running AC, microwave, etc.), up to 1 gallon per hour. Budget for 1 gallon per 2-3 hours of runtime for realistic mixed usage.