The right size for an RV comes down to one question: are you running the air conditioner, or not? Without AC, the essentials in most rigs, lights, the water pump, the fridge, charging, a few small appliances, are a light load that a mid-range portable handles comfortably. Add an air conditioner and everything changes, because its compressor demands a big jolt to start. So before you shop, sort your needs into those two buckets.
Two very different setups
It helps to see the split plainly. Here's what each side of that line tends to look like:
Essentials, no AC
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Adding the air conditioner
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Most of the frustration people run into comes from treating these two setups as the same job. They aren't. The essentials are easy; the air conditioner is the variable that decides how much generator you actually need.
Start with a simple load list
List what you'd genuinely run at the same time in the rig, and note the running watts of each from its label. Lights, the pump, charging, and the fridge together stay modest. Add them up, and that running total is what your generator's continuous rating has to cover, with headroom to spare. The startup surge idea carries straight over from home use, and it's worth a read if you haven't.
The mechanics of running versus starting watts are laid out in Running Watts vs. Starting Watts.
The air conditioner is its own question
RV air conditioners are the single biggest reason sizing goes sideways, because the compressor's starting surge is large and it depends on more than just the unit's label, elevation and outside temperature both play a part, as does whatever else is drawing power at the moment it kicks on. That's enough of a topic that it has its own guide.
Whether a given AC is supported is covered in detail in Can a Portable Generator Run an RV Air Conditioner?.
Why inverter power matters in a rig
An RV is full of sensitive electronics, control boards, a TV, laptops, chargers, and those prefer clean, stable power. The inverter models in this lineup produce exactly that, with low harmonic distortion, and they run quieter, which matters a great deal at a campground with quiet hours and neighbors nearby. For RV use, an inverter model is almost always the right call over an open-frame unit.
The trade-offs between the two types are spelled out in Inverter vs. Open-Frame Generator.
Placement still applies on the road
The safety rules don't relax just because you're camping. The generator runs outside and well away from the rig, never inside any compartment, including the generator compartment, and never under the RV. Keep it clear of windows and vents with the exhaust pointed away, because carbon monoxide is just as dangerous at a campsite as it is at home, more so when people are sleeping close by.
Full placement and CO guidance is in the Portable Generator Safety guide.
Where the lineup lands for RV use
For essentials without AC, a mid-range inverter model carries a typical rig with room to spare. If you intend to run an air conditioner, size up and check the AC question carefully first:
| Model | Continuous | Typical RV fit |
|---|---|---|
| S2500iS | 1.9 kW | Lightest essentials, weekend use |
| S3200iS | 2.6 kW | Essentials with more headroom |
| S3600iS | 3.0 kW | Essentials, and a starting point for AC questions |
| S4500iS | 3.6 kW | The most headroom for AC and mixed loads |
Not sure your AC will start on a given model? That's exactly the kind of thing to check before buying. Learn more
Questions people ask
Do I really need an inverter model for an RV?
For sensitive electronics and quiet campground use, yes, it's the sensible choice. Inverter power is clean and the units run quieter.
Can I run my RV air conditioner on a portable?
Sometimes, it depends on the AC's running and starting watts, elevation, temperature, and what else is running. See the dedicated AC guide.
What runs fine without AC?
Lights, the water pump, the fridge, charging, and small appliances are a light load a mid-range inverter handles easily.
Where do I put the generator at a campsite?
Outside and well away from the rig, never in a compartment or under the RV, with the exhaust pointed away from people.
Last updated: July 3, 2026 · Reviewed by: SIOKIUU Power Support