The Complete Buyer's Guide to Portable Generators

A portable generator is one of those purchases where it's surprisingly easy to spend $400 on the wrong thing and find out during a blackout. The market is flooded with models that look similar on a spec sheet but behave very differently when you actually plug a refrigerator into them. This guide walks through every decision point, in the order you should think about them, so the unit you end up with is one you'll still be glad to own three years from now.

What a portable generator actually is

A portable generator is a small internal-combustion engine connected to an alternator. The engine burns fuel — gasoline, propane, natural gas, or diesel — and spins a copper-wound rotor that produces alternating current. The result is electricity you can use at a campsite, jobsite, tailgate, or during a home power outage. "Portable" is a relative term: the smallest inverter units weigh under 30 pounds, while open-frame "portables" can push 250 pounds and require two adults and a ramp to move.

There are three broad categories. Open-frame conventional generators are the classic loud, gas-powered units you've seen on construction sites — high wattage, simple internals, cheaper per watt, but they run at a fixed 3,600 RPM regardless of load. Inverter generators use electronic conversion to produce cleaner power (low total harmonic distortion) and throttle their engines up and down based on demand, which makes them quieter and more fuel-efficient. Solar generators aren't really generators at all — they're large lithium battery banks with an inverter built in, charged from wall power or solar panels — but they're sold and shopped alongside fuel-burning units, so we'll treat them together.

The single most important spec: running watts

Manufacturers love to lead with peak (or "starting" or "surge") wattage because the number is bigger. What matters for sustained use is running watts — the continuous output the generator can sustain indefinitely. Peak wattage is only available for a few seconds, just long enough to absorb the inrush current when a motor (a fridge compressor, a sump pump, a power tool) kicks on.

A generator advertised as "5,000 starting / 4,000 running watts" can run loads totaling 4,000 watts continuously, with brief peaks up to 5,000. If you exceed running watts continuously, the generator will throw a breaker, overheat, or shut down on overload protection. We have a separate piece on running vs starting watts — read it before you pick a wattage class.

Fuel type: the next big fork

Fuel is the second decision because it ripples through everything else — runtime, storage, cost per kilowatt-hour, cold-weather performance, and how loud the generator is.

Gasoline

Gasoline is the default. Engines start easily in warm weather, fuel is available almost everywhere, and gas generators tend to produce the highest peak output for the money. The downsides are real: untreated gasoline degrades in as little as 30 days, ethanol-blended fuel attracts water that ruins carburetors during long storage, and pump availability collapses precisely when you need a generator most — during a regional outage when stations have no power for their pumps.

Propane (LPG)

Propane stores indefinitely. A 20-pound BBQ tank you bought five years ago is still ready to go. Propane burns cleaner, leaves less carbon deposit in the engine, and is usually a quieter combustion. The trade-offs: you typically get 10 to 15 percent less wattage on propane than gasoline, cold-weather starting can be harder below freezing, and you need to keep tanks on hand.

Dual-fuel and tri-fuel

Dual-fuel generators run on either gasoline or propane via a selector switch. Tri-fuel units add natural gas, which is appealing if your home has a gas line. For most buyers the dual-fuel premium (typically 10 to 20 percent over a gasoline-only equivalent) is worth it for the storage flexibility alone. The deeper dive lives in dual-fuel vs single-fuel.

Diesel

Rare in true portables. Diesel makes sense in the larger 8,000W+ class for jobsite or marine use, where fuel storage is already part of the equation, but you're shopping a smaller pond and prices run higher.

Solar / battery

Solar generators (technically portable power stations with solar input) burn no fuel at all, produce zero emissions, and can run indoors. They cost more per usable watt-hour than a fuel generator, and a multi-day outage will exhaust them unless you have substantial solar panel input. They shine for short outages, apartment use, and quiet camping. See solar generator vs gas for the head-to-head.

Inverter or conventional?

If your loads include anything with a sensitive electronic board — a modern refrigerator, a laptop, a CPAP, a phone charger, an LED TV — you want inverter technology, which produces a clean sine wave with total harmonic distortion (THD) typically below 3 percent. Conventional open-frame generators routinely run at 8 to 25 percent THD, which is fine for resistive loads (incandescent bulbs, heating elements, basic power tools) but can damage electronics over time.

The other reason to choose inverter is noise. Inverters throttle their engines to load, which means at quarter load they're whisper-quiet — typically 48 to 55 decibels at seven meters, less than a normal conversation. Conventional generators run at full RPM regardless of load and usually sit in the 68 to 78 decibel range, which is unpleasant at a campsite and outright illegal in many state and national park quiet hours. We unpack the full comparison in inverter vs conventional.

Runtime and tank size

Runtime is reported as "X hours at 25 percent load" or "at 50 percent load," and the percentage matters enormously. A generator that runs 14 hours at quarter load might run only 5 hours at 80 percent load. For overnight power, you want enough runtime to sleep through without refueling. For multi-day home backup, you're calculating gallons per kilowatt-hour and stockpiling fuel accordingly.

A useful rule of thumb: gasoline generators consume roughly 0.5 to 0.8 gallons per hour at 50 percent load for every 4,000 running watts. So a 4,000W unit at half load eats about a gallon every 1.5 to 2 hours.

Noise (dBA at 7 meters)

Generator noise is reported in dBA at a measurement distance — usually seven meters (about 23 feet). The number rises dramatically as you get closer; a 60 dBA reading at seven meters is roughly 73 dBA at one meter. A few reference points:

Safety features that should be non-negotiable

Three features have moved from "nice to have" to "table stakes" since 2019, and you should not buy a new generator that lacks them:

• CO shutdown. A built-in carbon monoxide sensor that kills the engine when ambient CO climbs above safe levels. Honda calls theirs CO-Minder, Westinghouse uses CO Sensor, DuroMax uses CO Alert. Whatever the brand name, this feature has saved lives in confined-space situations where users misjudged ventilation.
• Low-oil shutdown. Cuts the engine when oil drops below safe pressure. Without it, a slow leak or forgotten oil change destroys the engine in minutes.
• GFCI-protected outlets. Required by OSHA for jobsite use and a smart baseline for home use too.

Connectivity: outlets and parallel capability

Look at the outlet panel before you buy. The minimum useful set: two or more 120V 20A household outlets (standard three-prong), a 120V 30A locking outlet (TT-30R) for RV hookups, and ideally a 120/240V 30A or 50A locking outlet (L14-30R or 14-50R) if you plan to connect to a home transfer switch.

Parallel capability lets you connect two identical generators together to double the output. This is how someone with a Honda EU2200i can run a 13,500 BTU RV air conditioner — by adding a second EU2200i and a parallel cable for a combined 4,400 starting watts. Parallel is a smart upgrade path if you're not sure how much power you'll eventually need.

Weight, wheels, and how you'll actually move it

The 47-pound Honda EU2200i is genuinely one-hand portable. A 250-pound open-frame 10,000W unit is a two-person job with a ramp. Most mid-sized units (4,000 to 8,000W) ship with a wheel kit and folding handle, which makes flat-ground transport manageable but doesn't help with stairs, truck beds, or rocky terrain. If your storage and use spots aren't level and accessible, weight matters more than spec sheets suggest.

Warranty and brand support

Three-year warranties are standard across the mid-market (Champion, Westinghouse, WEN, DuroStar). DuroMax offers five years on some inverter models. Honda's three-year warranty is industry-respected because Honda actually services warranty claims through a dealer network rather than mail-back. Generac's longer residential standby warranties don't usually apply to their portable line.

Customer service experiences vary widely by brand and by year. Forum reports suggest Westinghouse and Champion are roughly comparable on parts availability, with WEN often praised for responsiveness on replacement units. Honda's dealer network gives it a structural advantage for in-person service. None of these brands are perfect, and most generators sold in the consumer market are assembled overseas regardless of which name is on the panel.

What to skip on the spec sheet

A few features get marketing space they don't deserve:

• "App connectivity." Useful for high-end Honda owners who want runtime monitoring from inside the house. For most users, you'll never open the app twice.
• Pure copper windings. Brands tout this, but the practical difference vs aluminum-copper alloy windings is small in a consumer unit.
• "Eco mode" or "Smart Throttle." Real on inverters, often marketing on conventional generators. If it's a true inverter, the throttle adjusts to load. If not, the badge is decoration.
• Peak wattage as the headline number. Always check running watts first.

Matching the generator to the use case

Camping and tailgating

Closed-frame inverter, 1,800 to 2,500 running watts, under 60 pounds, under 60 dBA at quarter load. Examples that have earned their reputation: Honda EU2200i (the benchmark), Westinghouse iGen2500/iGen2800, Champion 2500W inverter, WEN 56235i.

RV use

Inverter generator with a TT-30R outlet, 3,000 to 4,500 watts depending on AC size, parallel capable if you have a 13,500+ BTU rooftop AC. A 30-amp RV needs about 3,000W minimum to run the AC plus a few outlets; a 50-amp RV (with two AC units) wants 5,500W or larger. The roundup with current model picks is in best generators for RV use.

Home backup (essentials)

4,000 to 7,500 running watts will cover a refrigerator, furnace blower, a few lights, and a sump pump simultaneously. Dual-fuel is strongly recommended at this size. Add a manual transfer switch or interlock kit for code-compliant whole-circuit feeding.

Home backup (full)

9,000 to 12,500 watts to cover central air, a well pump, or an electric range. This is the upper end of "portable" — expect 200+ pounds and a wheeled frame. Beyond this you should be comparing portables against permanently installed standby units, which we cover in whole-house vs portable.

Jobsite

Open-frame conventional, 5,000 to 8,000 watts, OSHA-compliant GFCI outlets, full metal roll cage. Trade quiet operation and clean power for ruggedness and price-per-watt.

A pre-purchase checklist

1. Add up the running watts of every appliance you want to run at the same time. Multiply the largest motor-driven appliance's running watts by 2 to estimate its starting surge.
2. Add a 20 percent buffer above your running-watts total. Generators are healthiest running at 50 to 75 percent of capacity, not redlined.
3. Decide on fuel — gasoline, dual-fuel, or solar — based on your storage situation and outage duration risk.
4. Decide inverter or conventional based on what you're powering. Anything with a circuit board wants inverter.
5. Check the dBA spec at 25 percent load. If the manufacturer only lists peak dBA, the unit is loud.
6. Confirm CO shutdown and low-oil shutdown are included.
7. Confirm the outlet set matches your intended use (TT-30R for RV, L14-30R for transfer switch).
8. Check warranty terms, not just length — what's covered, what's not, and how claims are handled.

Where to buy

Generators are sold through Amazon, eBay, big-box hardware stores (Home Depot, Lowe's, Tractor Supply), generator specialists (Electric Generators Direct, Generator Mart), and direct from manufacturers. Pricing varies week to week — late spring and pre-hurricane-season often have promotional pricing, while a regional storm event will sell out inventory at any price.

The bottom line

The right portable generator is the one sized correctly for your loads, with the fuel flexibility that matches your storage and outage risk, with clean enough power for your electronics, quiet enough for where you'll use it, and from a brand whose customer service you can stomach when something inevitably needs attention. Spend a few hours on this decision and you'll have a piece of equipment that performs reliably for a decade. Rush it and you'll be back here in two years.