What to Look for in a Generator: Key Features Compared

A good generator matches the right type to your wattage needs, runs on a fuel you can store or reach, and includes real safety features like carbon monoxide shutoff. Everything else, from runtime to brand support, refines that core choice.

Those criteria shift with the job. A homeowner covering a fridge and furnace during winter outages needs something different from a contractor running saws or a camper charging phones.

Most buyers worry about two things: buying too little power and having the unit stall under load, or paying for capacity they never use. Safety is the quieter worry. A generator placed or wired wrong can hurt people, not just fail to help.

Before you compare any model, write down the three or four things you would actually plug in during an outage. That short list decides almost every choice that follows.

What Should You Look for in a Generator?

Generator buying criteria cover type, power output, fuel and safety features, plus supporting details like runtime, noise and portability. Each one shifts with how you plan to use the machine.

For home backup, power output and safe house connection come first, and a standby or larger portable unit makes sense. On a job site, durable outlets, tank size and easy transport matter more. For camping, weight and quiet running beat raw wattage, which points to a small inverter model or a battery power station.

Fuel cuts across all three. Gasoline is simple for occasional use, while propane or natural gas suits storm-prone homes that need long, low-fuss runtime. If you want the full buying process from first question to final pick, our guide on how to choose a generator walks through it step by step.

Which Type of Generator Fits Your Situation?

Home standby units cover the most of a house, portable generators balance output and flexibility, inverter models win on quiet and clean power, and power stations suit small, fume-free loads. Narrow to one type first, then look at specs.

Home Standby Generators

Home standby generators are permanently installed, start automatically when the grid drops, and can power most or all of a house. They suit owners who face frequent or long outages and don’t want to haul out a machine in the dark.

These units connect to a natural gas line or a large propane tank, so there is no refueling during an outage. An automatic transfer switch handles the handoff to your home circuits.

Output typically runs from 5,000 to 20,000 watts. That range covers anything from essential circuits to a whole house with central air. Cost runs about $3,500 to $7,000, and that doesn’t include installation, which needs a licensed electrician and often a permit.

The trade-off is commitment. You pay more upfront, and the unit stays put. For a renter or someone who faces one outage every few years, that’s more machine than the job needs.

Portable Generators

Portable generators are the flexible, lower-commitment option for backing up key circuits, job sites and outdoor work. You roll one out, fuel it and connect it by hand.

Models Consumer Reports tested ranged from 3,000 to 8,500 watts, and prices generally run from $400 to $2,000. That’s enough to run a refrigerator, some lights, a sump pump and a few electronics, but rarely a whole house at once.

You can feed appliances through heavy-duty extension cords or, with a transfer switch and inlet, feed household circuits directly. If you want the hookup steps, read up on how to power house with generator before storm season arrives.

Portables also earn their keep away from home. They run saws, compressors and tools where there’s no outlet.

The catch is routine. Someone has to set it up, refuel it and keep it outdoors, every time the power fails.

Inverter Generators

Inverter generators deliver cleaner power for electronics, run quieter and come in lighter frames than conventional portables. That makes them the pick for camping, tailgating and small loads.

The clean output matters for laptops, phones and modern appliances with sensitive circuitry. If you want the mechanics behind it, how does an inverter generator work explains the conversion step.

Tested models ranged from 900 to 7,600 watts, with prices from about $300 to $5,000. Weight swings widely. Compact camping versions start around 30 pounds, while large whole-house inverter units of 5,000 watts and up can top 250 pounds.

The output ceiling is the limit. Small inverter models can’t cover a whole house, and the big ones cost more than a comparable conventional unit. If your list includes a well pump or central air, check that the rating covers it before you commit.

Portable Power Stations and Solar Generators

Portable power stations and solar generators are battery-based, so they run without fumes, almost silently, and can be used indoors and in more places than any engine. They store limited energy, though, and struggle with heavy loads.

Two numbers matter. Capacity in watt-hours tells you how long the battery lasts, and output in watts tells you what it can run at once. A unit with plenty of watts but small capacity will power a space heater briefly and then quit.

You can recharge from a wall outlet, a vehicle or solar panels. They fit phones, laptops, CPAP machines, lights and small fans well.

For a multi-day outage with a fridge and furnace to run, they work as a supplement, not a replacement for a fuel-powered unit.

How Much Power Do You Need?

The right wattage comes from three checks: the starting versus running difference, the appliances that dominate your load, and the headroom you leave above that total. Do them in that order and the number mostly sets itself.

What Is the Difference Between Starting and Running Watts?

Running watts are the continuous power an appliance draws, while starting watts are the short surge a motor needs to get going. A generator rated only for your running load can stall when a compressor kicks on.

Motor-driven appliances are the culprits. Their starting demand runs two to three times their running power. Refrigerators, freezers, sump pumps, well pumps and air conditioners all work this way.

Lights, phone chargers and a laptop draw about the same at startup as they do while running, so they barely register.

Here’s how to use this. Add up the running watts of everything you want on at once. Then find the single motor-driven item with the biggest surge and add its extra startup demand on top. Stagger the startups, and the surge never stacks.

A generator’s label usually lists both a starting and a running rating. Size to the running number, and confirm the starting number covers your biggest motor.

Which Appliances Drive Your Total Load?

Water heaters, dryers, well pumps, refrigerators and HVAC are the high-draw items that decide generator size. A few of them can double your total.

Heating elements pull the most. A water heater needs roughly 4,000 to 5,000 watts, and a dryer 2,000 to 6,000 watts. Exact numbers vary by model, so check the nameplate on your own appliances.

Motors come next. Well pumps, refrigerators and air conditioners draw less while running, but they bring the startup surge from the previous section.

Lights, routers, TVs and chargers add little.

Most of these big loads don’t need to run during an outage. Skip the dryer, heat water before the power goes out, and run the well pump on a schedule. A home that wants several large appliances plus a window air conditioner often lands near 5,000 watts.

Cutting two or three heavy loads from your list can drop you a full size class. For a deeper walkthrough, see how big of a generator do i need.

How Much Headroom Should You Leave?

Size your generator 10 to 20 percent above your expected demand. That margin protects the engine and keeps voltage steady when loads change.

The common rule of thumb says don’t run a generator at its full rated output for long. A machine pinned at its limit works harder, runs hotter and wears faster. Voltage can also sag when a motor starts, and that stresses electronics.

The margin also covers estimation errors. Nameplate numbers are approximate, and it’s easy to forget a load.

Think about what you might add later. A new freezer, a window AC for a bedroom or a sump pump can push a tight setup over the edge. If you expect changes, step up one size class now, since resizing later means buying again.

To turn all this into a number, the steps in how to size a generator show the math in order.

Which Fuel Is Right for You?

Gasoline offers the easiest supply and strongest output, propane and natural gas store longer and burn cleaner, and dual or tri-fuel models let you switch between them. Match the fuel to your outage pattern and your storage space.

Gasoline

Gasoline is the most common portable fuel because it’s easy to find and gives high output. It asks more of the owner in storage and upkeep.

You can buy it at any station, which is a big advantage until a widespread outage empties the pumps and the lines. It also has a short shelf life. Left in a tank or can for months, it goes stale and can gum up a carburetor.

Good habits fix most of that. Add fuel stabilizer when you store gas, rotate your cans, and don’t leave a full tank sitting all year.

Refueling is another cost. A long outage means repeated trips, and you have to let the engine cool before filling. Running a generator also burns more than most people expect, so check how much gas will your generator use before you decide how many cans to keep.

For occasional use and the best power per dollar, gasoline is hard to beat.

Propane and Natural Gas

Propane and natural gas burn cleaner and store longer than gasoline, but they deliver less output. Propane lives in tanks you can keep for years, while natural gas comes through a line from the utility.

Propane stores well, so a few filled cylinders sit ready without going bad. A bulk tank gives you days of runtime.

Natural gas removes refueling entirely. The risk is supply. Pressure can drop or service can be shut off after a major storm or earthquake. If you live where hurricanes hit, generator hurricane preparation covers fuel planning in more detail.

Both fuels produce less power than gasoline from the same engine. A unit rated at a given wattage on gasoline will deliver less on propane or natural gas, so size up if you plan to use them.

They suit homeowners who want low-maintenance fuel and expect long outages.

Dual Fuel and Tri-Fuel Models

Dual fuel and tri-fuel generators let you switch between fuels, usually gasoline and propane, with tri-fuel adding natural gas. The price of that flexibility is lower output on the alternative fuels.

The benefit shows up when supply gets tight. If gas stations are dry, you can connect a propane cylinder. If you have a natural gas line, a tri-fuel model can tap it.

Expect less power on propane or natural gas than on gasoline. Check the rating for each fuel on the label, and make sure your essentials fit within the lowest one.

These models fit people who face varied conditions: a storm-prone region, a mix of home and job-site use, or anyone who wants a backup plan for their backup plan.

If you know you’ll only ever use one fuel, a single-fuel model is simpler.

What Runtime, Noise and Portability Features Matter?

Daily use comes down to how long a tank lasts, how loud the engine runs and how easy the unit is to move and start. Check all three before you buy.

Runtime and Tank Size

Runtime depends on tank size and load level together, so a bigger tank doesn’t guarantee a longer run. A reasonable target is at least 10 hours on a tank for portable units, enough to cover an overnight outage without a midnight refuel.

Manufacturers rate runtime at a specific load, often a partial one. Run heavier and the tank empties faster. That’s why a published figure is a ceiling, not a promise.

Continuous running has limits too. Engines need oil checks and rest, and long outages mean planned refueling and shutdowns.

Think about your pattern. If your outages last a few hours, runtime barely matters. If they last days, a larger tank or a fuel hookup that avoids refueling saves effort and risk. The question of how long can a generator run goes deeper on those limits.

Noise Level

Noise differs by type: inverter models are quietest, conventional portables are loudest, and standby units generally sit in between. It affects use at home, at a campsite and near neighbors.

Inverter engines adjust speed to match the load, so they often run quietly under light demand. Conventional portables hold a steady speed and sound the same whether you’re powering a lamp or a saw.

Standby units run outdoors against the house and are generally easier to live with than portables, though you’ll still hear them.

Noise rules apply. Campgrounds often limit generator hours or volume, and neighbors notice an engine running all night. Manufacturers list decibel ratings, but they’re measured at specific distances and loads, so compare them on equal terms.

If you’re camping, tailgating or living on a small lot, quiet is worth prioritizing.

Weight, Wheels and Starting Features

Weight, wheel kits and electric or remote start decide how easy a generator is to move and start in an emergency. A heavy unit without wheels is a real problem when the power is out and it’s dark.

Think about handling first. Can you get it from the garage or shed to the yard alone? Is there a path without steps? A wheel kit and a handle make a big difference.

Storage footprint matters too. Measure the space before you buy.

Starting is the other piece. Electric start means a button instead of a pull cord, and remote start lets you fire it up from inside. These matter most when a generator sits unused for months, because a cold, tired engine is harder to pull-start, especially for older owners or in cold weather.

Which Safety Features Should a Generator Have?

Safety comes down to a CO sensor with automatic shutoff, outdoor placement with proper clearance, and a transfer switch for house connection. Treat these as buying criteria.

Carbon Monoxide Protection

Carbon monoxide is an odorless, deadly gas from running engines, and a CO sensor with automatic shutoff reduces the risk by stopping the generator when levels build up near it.

Many newer portable generators include this feature. If the sensor detects dangerous CO, the engine shuts down. Look for it on the spec sheet, since it can be a deciding factor between two otherwise similar models.

It supports good habits but never replaces them. The sensor only measures near the generator. The safest approach is still to run the unit outdoors and well away from the house.

Alarms inside the home matter just as much. Install battery-powered or battery-backup CO alarms on every level and near sleeping areas. CO can seep in through gaps, and an alarm gives you warning even when everything seems fine.

Never run any fuel-burning generator in a garage, basement, shed or enclosed space, even with the door open.

Safe Placement and Operation

A portable generator belongs at least 20 feet from the house, with exhaust pointing away from windows, doors and vents. Place it on a dry, level surface and let it breathe.

That distance applies to the home and to equipment like central or window air conditioners, which could pull exhaust inside.

Rain and moisture are a hazard around electricity. If you need protection, use a covered but ventilated setup, like an open-sided canopy designed for generators. Don’t enclose it.

Follow the manual for grounding. Some units need a ground rod, and others don’t.

Refuel only when the engine is off and cool. Spilled gas on a hot engine can ignite.

Cords should be rated for the load and kept free of damage. The basics of how to use a generator are worth reviewing before you need one.

Transfer Switch and Safe House Connection

A transfer switch is the safe way to feed household circuits because it prevents backfeed into the utility lines. Without one, you shouldn’t connect a generator to your home wiring.

Backfeed sends power back out through the grid, where it can injure or kill utility workers repairing lines. A transfer switch isolates your house from the grid before the generator connects.

There are two main types. A manual switch makes you flip it yourself, while an automatic one detects the outage and switches on its own, as with standby systems.

Extension cords alone work, but they only power a few appliances, and you’ll run cords through doors or windows. A transfer switch lets you power hardwired items like furnaces and well pumps. Installation needs a licensed electrician, and you can read how to install a generator transfer switch for what that involves.

Does Brand Reliability Really Matter?

Brand reliability matters most through parts and service access, owner-reported reliability and engine pedigree. A generator you can’t get repaired is a generator that fails when you need it.

Start with support. Check whether parts are stocked and whether authorized repair shops exist near you. A fix that takes weeks to source is no use in a storm season.

Owner reviews come next. Look for patterns over several years, such as starting trouble after storage, fuel system issues or failed controls. One bad review means little, but a repeated complaint tells you something.

Engine pedigree is the third check. Many generators from different brands use engines from a handful of engine makers, and a proven engine often means easier parts.

Names like Generac, Honda and Briggs & Stratton come up often, and that’s not an endorsement. Some brands draw weak reviews because of thin service networks or hard-to-find parts, not just build quality. Judge by support and track record, not the name on the housing.

What Does a Quick Generator Buying Checklist Look Like?

Work through use case, type, wattage, fuel, safety features, runtime and noise, and brand and support, in that order. Each step narrows the next.

• Use case: home backup, job site or camping
• Type: standby, portable, inverter or power station
• Wattage: running load, largest startup surge, plus a margin
• Fuel: gasoline, propane, natural gas or a multi-fuel setup
• Safety: CO shutoff, safe placement, transfer switch
• Runtime and noise: tank life and neighbor tolerance
• Brand and support: parts, service and owner track record

If two models tie, the one with better safety features and local support usually wins.

Most apartment leases and condo bylaws ban fuel-burning generators on balconies and patios, and carbon monoxide doesn’t care what the lease says. A renter with a warm fridge and no yard still needs some way to keep essentials running before the next storm. What can a building-friendly backup actually power, and what do you do if the rules rule out an engine?

Can You Use a Generator Indoors or in an Apartment?

No. A fuel-burning generator never belongs indoors, in a garage or on a balcony, because its exhaust carries carbon monoxide that can build up fast, even in open or ventilated spaces.

Engines need to run outdoors with open air around them, and an apartment balcony usually fails that test. Fumes drift back inside through doors and windows, and neighbors share the risk.

Apartment dwellers have safer options. A battery-based power station runs silently and without exhaust, so it can sit indoors. It can charge phones, run a laptop, power lights and keep a small device like a CPAP going. It struggles with a refrigerator for long or anything with a heating element.

Some buildings also have their own backup, often a generator that covers elevators, hallway lights and sometimes common areas. Ask management what it covers.

Match the backup to the loads that matter most, and keep any engine well outside.

What Local Rules Can Limit Where You Run a Generator?

Noise ordinances, HOA restrictions and permit requirements vary by city, county and community, so check them before you buy. Learning about them after the purchase can leave you with a machine you can’t use.

Noise ordinances may limit hours or decibel levels. Some HOAs restrict where a generator can sit, whether it can be visible, or whether permanent installs are allowed at all.

Permanent installs usually involve more. A standby generator or a transfer switch typically needs a permit, and the work generally calls for a licensed electrician. Gas line connections have their own requirements.

A quick call to your city or county office answers most of this, and your HOA documents cover the rest. Ask about setback distances, noise limits and inspection requirements.

If rules are strict, an inverter model or a battery power station may fit where a conventional portable wouldn’t.

Why Do Stored Generators Fail to Start, and How Do You Prevent It?

Stored generators fail mostly because of stale fuel and gummed carburetors, and you prevent it with fuel stabilizer, battery upkeep and regular run-ups. A few habits separate a unit that fires on the first pull from one that won’t.

Gasoline left for months degrades and leaves varnish in the carburetor, which blocks small passages. Add stabilizer when you fill the tank or cans, or run the carburetor dry before long storage. If yours still balks, generator won’t start walks through the usual causes.

Electric-start models need a healthy battery. Keep it charged, and use a maintainer if the unit sits for long stretches.

Run the generator periodically, for a short session under a light load every month or two. That circulates oil, burns off fresh fuel and shows you problems while there’s still time to fix them.

Check oil and replace it on schedule. These small steps protect the purchase far better than any extra feature.

Which Extra Features Are Worth Paying For, and Which Go Unused?

Extras worth paying for protect the engine and speed up starts, so features that earn their place are different from features that often go unused. Higher-end models pay off for heavy or frequent use, while a simpler one covers light needs.

Features That Earn Their Place

Low-oil shutoff, electric start, a fuel gauge, quality outlets and parallel capability are the extras that matter in real use. Each pays off in a specific situation.

Low-oil shutoff stops the engine before it runs dry, which protects it if you forget a check. Electric start helps anyone who dreads yanking a cord in the cold. A fuel gauge saves guessing during a long run.

Outlets matter if you use different tools or appliances. Having the right types, including a twist-lock outlet for a transfer switch cable, avoids adapters.

Parallel capability lets you link two compatible small inverter units for more power, and it’s useful if you want portability now with room to grow.

Higher-end models make sense for frequent users, home backup owners and anyone who relies on the machine daily. To weigh that question honestly, are expensive generators worth it covers where the extra spend returns value.

Features That Often Go Unused

Oversized capacity and unneeded smart controls are the extras that rarely change results for typical buyers. A basic model covers the need when your plan is simple.

Capacity beyond your actual load just means a bigger, heavier, thirstier machine. If your list tops out at a fridge, lights and a few chargers, a mid-size unit does the job.

Smart features like app monitoring, Wi-Fi connectivity and elaborate displays look good in a listing. Many owners never open the app after the first week.

A better approach is to buy for the plan you wrote down earlier. Pick the type, fuel and wattage that match it, add the safety essentials, and stop there. For a sense of where the dollars go, how much does a generator cost breaks it down.

Generator Buying FAQs

What is the rule of thumb for how much to load a generator?
Avoid running a generator at its full rated output for long periods. Keeping your expected load a bit below the limit reduces engine wear and keeps voltage steadier. Stagger motor startups so surges don’t stack, and add a modest margin above your calculated total so small mistakes don’t overload the unit.

What size generator does a typical home need?
Add the running watts of the appliances you actually want powered, then check the largest motor’s starting surge and add a margin. Homes running a few big appliances plus a window air conditioner often land at a mid-size portable or a standby unit. Skipping heavy loads like the dryer lowers the number.

Can a portable power station replace a gas generator?
For short outages and small loads, yes. Power stations run phones, laptops, lights and medical devices quietly and without fumes. For multi-day outages or heavy loads like a furnace blower or well pump, stored battery energy runs out fast, so a fuel-powered unit remains the more dependable choice.

Do I need a transfer switch?
If you want to power hardwired circuits like a furnace or well pump, yes. A transfer switch prevents backfeed into utility lines and lets you run household circuits safely. If you only plan to power a few appliances through extension cords, you can skip it, but the cords limit what you can run.