Portable Generator Buying Guide (2026): Size, Fuel, Outlets and Safety
Affiliate disclosure: This post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases. The example generators below link to manufacturer pages because we couldn’t verify their Amazon listings for this guide. No manufacturer paid for placement.
How we evaluated: WildJoule has not bench-tested these generators. This portable generator buying guide uses manufacturer specifications from Honda, Champion (via a dealer spec page) and Westinghouse, plus Generac’s published THD guidance, checked October 7, 2026.
This portable generator buying guide comes down to four numbers: the running watts you actually need, the starting watts your biggest motor demands, the outlet your house or RV plugs into, and how loud the thing is at the distance you’ll be sleeping. Get those right and the brand matters less than most reviews suggest. Get one wrong and you end up with a generator that trips every time the well pump kicks on.
The short answer
For an RV or camping, buy a 2,000–3,500 W inverter generator with a TT-30R outlet if you need it. For home backup through a transfer switch, buy a 7,000–10,000 W dual-fuel unit with an L14-30R or 14-50R outlet. Expect roughly 10% less output on propane than on gasoline. Never run any of them indoors or in a garage.
Let me put this plainly: I haven’t run these generators, and I don’t have one in a shed out back. What I do have is a long history with power cuts that come without warning, which is exactly the situation a generator is bought for. So I worked from the spec sheets and the safety guidance, and I tried to keep this to the decisions that actually change what you buy.
Step 1: size the generator to your loads
Add up the running watts of everything you want on at the same time. Then find the single load with the biggest starting surge, usually a well pump, fridge compressor, AC or furnace blower, and add its extra starting watts on top. Motors commonly draw two to three times their running watts for a second or two at start-up; the label or manual gives the real figure.
A rough example with illustrative numbers: a fridge (say 200 W running), a sump pump (say 800 W running) and lights and chargers (300 W) add to about 1,300 W. If the sump pump needs an extra 1,300 W to start, you want at least 2,600 W of starting capacity, more if the fridge compressor might kick on at the same moment. A 2,200 W inverter generator would struggle; a 3,500 W running / 4,500 W starting unit has margin. Check your own labels, because these vary a lot by model. Our household power usage calculator helps if you don’t know your loads.
Step 2: inverter or conventional
Inverter generators produce cleaner power and throttle the engine down at light loads, so they’re quieter and sip fuel when you’re only charging phones. Conventional (open-frame) generators run at fixed speed, are louder, and give you more watts per dollar. Generac says power under 6% total harmonic distortion counts as clean for sensitive electronics, that typical portable generators produce 9–15% and some reach 30%, and that its inverter models produce 3% or less. Our inverter generator vs conventional generator comparison covers this in detail.
Step 3: pick the fuel
| Fuel | Pros | Cons |
|---|---|---|
| Gasoline | Highest output, easy to find | Goes stale in months without stabiliser; hard to store in quantity |
| Propane | Stores for years, cleaner carb | About 10% less output on the same engine |
| Dual-fuel | Switch to whichever you have | Slightly more expensive; still check the propane rating |
The propane penalty shows up clearly in the spec sheets. The Westinghouse WGen9500DF is rated 9,500 W running on gasoline and 8,500 W on propane. Champion’s 4,500 W dual-fuel inverter (model 200988) is listed at 3,500 W running on gasoline and 3,150 W on propane. Both are roughly a 10% drop. Size to the propane figure if propane is what you’ll actually run.
Step 4: match the outlets to what you’re plugging in
- TT-30R (30 A, 120V): the standard RV plug. Champion’s 200988 has one; many small inverter generators don’t.
- L14-30R (30 A, 120/240V): the twist-lock most transfer switches and inlet boxes expect.
- 14-50R (50 A, 120/240V): found on larger units like the WGen9500DF; useful for 50 A RVs and bigger inlets.
- 5-20R household outlets: fine for extension cords, but use a cord rated for the load. Our generator extension cord picks cover gauge and length.
Portable generator buying guide: three example generators
| Honda EU2200i | Champion 200988 | Westinghouse WGen9500DF | |
|---|---|---|---|
| Type | Inverter, gas | Inverter, dual-fuel | Conventional, dual-fuel |
| Running watts | 1,800 W | 3,500 W gas / 3,150 W LP | 9,500 W gas / 8,500 W LP |
| Starting / peak | 2,200 W | 4,500 W | 12,500 W gas / 11,200 W LP |
| Noise (maker-stated) | 48–57 dB(A) | 61 dBA | 74 dBA |
| Weight | 47.4 lb | 103 lb | 211 lb (dry) |
| Key outlets | 120V household | TT-30R, 5-20R | L14-30R, 14-50R, GFCI 5-20R |
| CO shutdown | CO-MINDER | Not listed in the spec we found | No CO sensor |
| Warranty (residential) | 3 yr | 3 yr | 3 yr |
These aren’t ranked picks, and this portable generator buying guide isn’t a best-of list. They show how different the three size classes are. The Honda is light and quiet enough for a campground and can be paired with a second unit for 4,400 W through its parallel feature. The Champion covers a travel trailer with a 30 A plug. The Westinghouse is a home-backup machine: a transfer-switch outlet, 240V for a well pump, and the weight and noise that come with it.
Note the Honda EU2200i model listed on Honda’s page is marked as not available in California, and Westinghouse lists the WGen9500DF as not CARB compliant. Californians should filter for CARB-compliant models first.
Step 5: safety is part of the purchase
Carbon monoxide is the reason generators kill people. Run a generator outdoors, far from windows, doors and vents, and never in a garage, even with the door open. A unit with automatic CO shutdown (Honda’s CO-MINDER, or similar systems from other brands) adds a layer of protection, but it doesn’t replace distance. Our portable generator carbon monoxide safety guide covers placement, and the CPSC portable generator safety center has the official guidance.
Connecting to a house needs a transfer switch or interlock installed by an electrician. Back-feeding through a dryer outlet with a double-male cord can energise the utility line and injure line workers.
Accessories worth budgeting for
A cover that lets you run in rain, wheels for a 200 lb frame, a proper cord, and a parallel kit if you’re pairing two inverters. Our generator accessories guide links to each: running covers, wheel kits and parallel kits.
When a generator isn’t the right buy
If your outages are short and your loads are small, a battery power station may serve you better: no fumes, no noise, no fuel to rotate. If outages run for days, a generator’s refuelling advantage is hard to beat. Our generator vs power station comparison works through that decision, and the home backup power guide covers hybrid setups that use both.
Two decisions trip up more buyers than wattage. The first is fuel: our propane vs gas generator comparison shows the roughly 10% output you give up on propane and what you gain in storage. The second is air conditioning: a generator for central air conditioner loads needs 240 V and a plan for the compressor’s start-up surge. For a quiet 120 V unit with long run times, see the Honda EU3000iS review.
Still unsure about step 1? Our what size generator do I need guide has a 17-appliance wattage chart and a worked example. And once you’ve picked a generator, a transfer switch for your generator is the safe way to feed house circuits.
Frequently asked questions
What size portable generator do I need?
Add the running watts of everything you’ll run at once, then add the extra starting watts of the biggest motor. Most RV owners land at 2,000–3,500 W; most home-backup setups at 7,000–10,000 W.
Is propane or gasoline better for a generator?
Propane stores far longer and is easier to keep on hand, but expect about 10% less output. Dual-fuel gives you the choice.
Can a portable generator run my whole house?
Usually not every load at once. A 9,500 W unit through a transfer switch can cover the essentials, including a 240V well pump, if you manage big loads like electric dryers and ranges.
Are inverter generators worth it?
For camping, RVs and sensitive electronics, yes: they’re quieter and produce cleaner power. For home backup where watts per dollar matters most, a conventional unit is often the better value.
Do I need a transfer switch?
To power house circuits, yes, or an approved interlock. Back-feeding through an outlet is dangerous and illegal in most places.
Two follow-ups for specific jobs: generator for well pump sizing by horsepower, and the Champion 4500W inverter generator review if you want one dual-fuel unit for a 30A trailer and outages.
Load-by-load sizing guides: well pump, sump pump, furnace and RV air conditioner. For fuel planning, see how long will a generator run on a tank.
Last updated: October 7, 2026. This portable generator buying guide uses manufacturer-stated specs, not WildJoule test results. We do not display live prices.