Portable Generators:
The Complete Guide
for Homeowners
How to choose the right portable generator for your home — what size you need, which type to buy, the best brands, and the safety rules you can’t ignore.
The Affordable, Flexible Backup Power Option
A portable generator is a gasoline-powered engine that generates electricity when the grid goes down. Unlike a standby generator, you store it in your garage, wheel it outside when you need it, fill it with gas, and start it manually. It’s not as convenient — but it costs a fraction of the price.
A quality portable generator in the $800–$1,500 range can keep your refrigerator running, power some lights, run a window AC unit, and charge your devices. For homeowners who experience occasional short outages and don’t want to spend $10,000 on a standby system, a portable generator is often the right answer.
The critical caveat: portable generators produce carbon monoxide and must always be used outdoors, at least 20 feet from any window or door. CO poisoning kills dozens of people every year during storm outages. This is the one rule you cannot compromise on.
Is a Portable Generator Right for You?
A portable generator makes sense if you:
- Want backup power at a much lower upfront cost than standby
- Only experience outages a few times per year, lasting a day or less
- Don’t need to power central AC — just essentials
- Also want to use it for camping, job sites, or tailgating
- Rent your home and can’t install permanent equipment
- Are willing to manage fuel storage and manual startup
Which Type Do You Need?
Not all portable generators are the same. There are three main types, each suited to different situations.
Dual-Fuel Generator
Runs on gasoline or propane. The best choice for home emergency use — propane stores indefinitely, so you’re always ready even if gas stations are out after a storm.
Inverter Generator
Quieter, cleaner power output. Ideal for sensitive electronics (laptops, TVs, medical devices). More fuel-efficient but generally lower wattage and higher cost.
Conventional Portable
The most common and affordable type. Loud, simple, and reliable. Great if you just need raw wattage to power appliances and aren’t worried about noise or clean power.
What Size Portable Generator Do You Need?
Portable generator power is measured in watts. The key is adding up the wattage of everything you want to run at the same time.
| Generator Size | What It Can Power | Typical Cost | Best For |
|---|---|---|---|
| 2,000–3,500W | Phone charging, lights, small TV, fan | $300–$700 | Camping, very basic backup |
| 4,000–5,500W | Fridge, lights, outlets, window AC (small) | $500–$1,000 | Apartment or small home essentials |
| 7,000–9,000W Most Popular | Fridge, lights, AC, sump pump, well pump | $800–$1,800 | Average home — covers most needs |
| 10,000–12,000W | Nearly whole-home coverage (no central AC) | $1,500–$3,000 | Larger home, maximum portable coverage |
The Wattage Rule You Need to Know
Every appliance has two wattage numbers: running watts (what it uses normally) and starting watts (the surge needed to kick on). Your generator’s peak wattage must handle the highest starting surge. A refrigerator might run at 150W but need 600W to start — that surge matters.
The most common mistake: buying a generator that’s just barely big enough for your running load, then having it trip or struggle every time the fridge compressor kicks on. Build in 20–25% headroom above your calculated load.
What Does a Portable Generator Cost?
The generator itself is just part of the picture. Here’s the full cost to budget for.
Generator Unit Cost
A good-quality portable generator for home use runs $700–$1,800. You can find cheaper units, but sub-$500 generators often have reliability issues and poor surge handling. Don’t cheap out on something you’re counting on during a storm.
Transfer Switch — Don’t Skip This
To safely connect a portable generator to your home’s wiring, you need a manual transfer switch installed by an electrician. Cost: $300–$800 installed. Without one, you’re running extension cords — which works but is inconvenient and won’t power hardwired appliances like your furnace or well pump.
Never backfeed power through an outlet into your home’s wiring without a transfer switch. This is called “backfeeding” and it’s extremely dangerous to utility workers and can cause fires.
Ongoing Costs
- Gasoline: A 7,500W generator uses roughly 0.6 gallons/hour at half load. A 3-day outage at 12 hours/day = about 22 gallons
- Fuel stabilizer: $8–$15/year to keep stored gas fresh
- Oil changes: Every 100 hours of use, about $20 in supplies
- Generator cover: $30–$80 to protect it in storage
Best Portable Generator Brands
Four brands dominate the portable generator market. Here’s how they stack up.
The gold standard for portable generators. Honda’s EU series inverter generators are legendary for reliability, fuel efficiency, and quiet operation. They cost more — but they last 20+ years with proper care. If you want the best, buy Honda once.
Full Honda Review →The most popular brand for budget-conscious buyers. Champion’s dual-fuel models in the 7,500–9,000W range are a favorite for home backup. Not as refined as Honda, but reliable and well-supported with a 3-year warranty and good parts availability.
Full Champion Review →Westinghouse packs in a lot for the price — electric start, remote start, dual-fuel capability, and solid wattage. Their iGen and WGen series are consistently well-reviewed. A strong choice if you want more features at a mid-range price point.
Full Westinghouse Review →Right alongside Honda at the top of the inverter generator market. Yamaha’s EF series is ultra-quiet, fuel efficient, and produces clean power for sensitive electronics. Ideal for homeowners who prioritize quiet operation over raw wattage.
Full Yamaha Review →Portable Generator Safety — Read This First
Carbon monoxide from portable generators kills dozens of Americans every year. These rules are non-negotiable.
Never Run Indoors
Never operate a portable generator inside your home, garage, basement, or any enclosed space — even with windows open. Carbon monoxide is odorless and invisible. It can reach dangerous levels in minutes. Every year, people die running generators in attached garages.
20-Foot Rule
Keep the generator at least 20 feet from any window, door, or vent — including your neighbor’s. Exhaust must point away from all structures. CO can drift into your home even through closed windows if the generator is too close.
Install a CO Detector
Put a battery-operated carbon monoxide detector on every level of your home before you ever run a generator. Test it monthly. This is your last line of defense if something goes wrong.
Never Refuel While Running
Always turn the generator off and let it cool for at least 2 minutes before adding fuel. Gasoline spilled on a hot engine can ignite instantly. Store fuel in approved containers away from the generator.
Do You Need a Transfer Switch?
A transfer switch is an electrical device installed next to your main panel that safely connects your generator to your home’s wiring. There are two types:
Manual Transfer Switch ($300–$800 installed)
The most common choice for portable generators. You manually flip a switch to transfer power from the grid to your generator. It protects utility workers from backfed power, prevents damage to your generator when grid power returns, and lets you power hardwired circuits like your furnace, well pump, and hardwired lighting. An electrician installs it in a few hours.
Interlock Kit ($100–$300 installed)
A less expensive alternative — a metal bracket that prevents your main breaker and generator breaker from being on at the same time. Functionally similar to a transfer switch at a lower cost. Not available for all panel types but worth asking your electrician about.
Running on Extension Cords (No Transfer Switch)
You can run extension cords directly from your generator to appliances — this is how many people use portable generators. It works fine for refrigerators, lamps, and devices. The downsides: you can’t power hardwired circuits, cords run through doors or windows (a security and weather risk), and it’s less convenient. If you go this route, use heavy-duty 12-gauge extension cords rated for outdoor use.
Pros and Cons of Portable Generators
- Much lower upfront cost than standby ($700–$1,800 vs. $5K–$15K)
- No professional installation required for basic use
- Can be used for camping, job sites, tailgating
- Easy to store in garage when not needed
- Available immediately — no lead time or permit process
- Dual-fuel models run on propane (infinite shelf life)
- Must be started and managed manually during an outage
- Requires fuel storage and refueling every 8–18 hours
- Carbon monoxide risk — outdoor use only, 20 feet from home
- Loud — 65–75 decibels at 23 feet
- Can’t power central AC or whole home
- Gasoline goes stale in 30–60 days without stabilizer
- Needs transfer switch for hardwired circuits
Frequently Asked Questions
No. Even with the garage door fully open, carbon monoxide can accumulate to dangerous levels inside the garage and drift into your home. Always run portable generators outdoors, at least 20 feet from any windows, doors, or vents. There are no exceptions to this rule.
Most manufacturers recommend running for no more than 500 hours before a full service. During a single outage, you can run continuously as long as you have fuel and stop periodically to let it cool slightly when refueling. Change the oil after every 100 hours of use.
Generally no — at least not with a typical portable generator. Central AC units require 15,000–20,000+ starting watts, which exceeds most portable generators. Window AC units (5,000–12,000 BTU) are much more manageable and can typically be run on a 7,500W+ generator. If whole-home AC during outages is a priority, a standby generator is the right solution.
Run the fuel tank dry or add fuel stabilizer before storing for more than 30 days. Store in a cool, dry place — a garage or shed works fine. Change the oil before extended storage. Start it up and run it for 20–30 minutes every 3 months to keep the engine in good condition. Keep a fresh spark plug on hand.
Running watts is the continuous power an appliance needs to operate. Starting (or surge) watts is the temporary extra power needed to start a motor-driven appliance like a refrigerator, AC, or sump pump. Your generator’s rated wattage must handle the highest starting surge in your home. Always check both numbers when sizing — a generator that handles your running load may still trip on the starting surge.