Every November, as the first ice storm warnings appear, the same conversation happens in hardware stores across the country. A homeowner stands in front of a row of generators, from a suitcase-sized unit to a boxed machine the size of an air conditioner, and asks which one will keep the furnace and the fridge going. The honest answer is that the question is incomplete. The right generator depends on what you need to run, how long outages last where you live and how much effort you are willing to put in when the lights go out.
Three families of machines cover almost every household: conventional portable generators, inverter generators and permanently installed standby generators. They differ in cost, noise, convenience and the work required to use them safely. This guide explains each, shows where each fits and gives you a sensible way to choose before the next storm rather than during it.
Short answer: a conventional portable gives the most watts per dollar for occasional outages, an inverter is quiet and clean for essentials, and a standby unit is for frequent or long outages when you want it automatic.
The one safety rule that applies to all of them
Before anything else, there is a rule that must be stated every time generators come up. A running generator produces carbon monoxide, a colorless, odorless gas that kills people every winter. A portable generator must never be run indoors, in a garage, in a crawl space or near a window, door or vent, even with the door open. Standby generators are installed outdoors at a distance set by code. If anyone in the household feels dizzy, nauseous or unusually tired during an outage, get everyone into fresh air and call emergency services. We do not give medical advice, and no article replaces a carbon monoxide alarm and the manufacturer’s manual.
Conventional portable generators
A portable generator is a wheeled, open-frame machine with an engine, usually running on gasoline and in some models propane or both. It sits outside, and you connect appliances through extension cords or, with a properly installed transfer switch or inlet, through the house wiring.
The lowest cost per watt. Large output for the price, enough in bigger models to run a furnace blower, a refrigerator, lights and a sump pump. Widely available and easy to service.
Loud, often loud enough to annoy neighbors. Fuel must be stored, refreshed and handled. You have to move it, start it, refuel it every few hours and keep it dry. The output voltage can be less clean than an inverter, which matters for sensitive electronics.
Households with occasional outages, a modest budget and someone willing to run the machine by hand.
Inverter generators
An inverter generator produces power in a way that creates a cleaner, steadier output and lets the engine speed change with the load. The result is a machine that is quieter and more fuel-efficient than a conventional portable of the same size.
Quieter, lighter and cleaner power for phones, laptops and modern appliances. Good fuel economy at light loads. Many can be linked in pairs for more output.
Higher cost per watt. Smaller maximum output than large conventional units. Still requires fuel handling and outdoor operation.
Households that want to run the essentials quietly, camping and tailgating owners and anyone whose neighborhood or rules make noise a problem.
Standby generators
A standby generator is installed permanently beside the house, connected to the home’s natural gas or propane supply and to the electrical panel through an automatic transfer switch. When the grid fails, it starts itself within seconds.
Automatic. No fuel to carry, no cords to run, no one to stand in the cold at midnight. Large output, often enough for the whole house. Can run for days on a piped fuel supply.
The highest total cost, including the machine, installation, permits and a concrete or composite pad. Installation must be done by licensed professionals and is subject to local code and utility requirements. Needs regular maintenance, like a car engine.
Households with frequent or long outages, medical or business reasons for continuous power, or homeowners who simply do not want to think about it.
Side by side
- Relative cost. Conventional portable: Lowest. Inverter portable: Moderate. Standby: Highest, plus installation.
- Noise. Conventional portable: Loud. Inverter portable: Quieter. Standby: Moderate, depends on enclosure.
- Output range. Conventional portable: Medium to large. Inverter portable: Small to medium. Standby: Medium to whole-house.
- Fuel. Conventional portable: Gasoline, propane or dual fuel. Inverter portable: Gasoline or dual fuel. Standby: Natural gas or propane.
- Effort in an outage. Conventional portable: High. Inverter portable: High. Standby: Very low.
- Installation. Conventional portable: None, but safe hookup needs planning. Inverter portable: None. Standby: Licensed professionals and permits.
- Best for. Conventional portable: Short outages, higher load on a budget. Inverter portable: Quiet essential loads. Standby: Frequent outages, whole-house convenience.
How to decide: four questions
- A few hours twice a year suggests a portable unit or even a power station. Multi-day outages suggest either a large portable with a solid fuel plan or a standby unit.
- Write a load list. Our guide to sizing a generator shows how. A refrigerator, furnace fan and a few lights need far less than a whole house.
- A machine that has to be started in freezing rain by someone who is away or unwell is a poor fit. If operation is a concern, standby is the reliable answer.
- Add the machine, cords or inlet, transfer equipment, fuel storage and maintenance.
Fuel matters more than most people expect
A generator is only as good as its fuel. Gasoline goes stale in a few months unless treated and stored correctly, which is the usual reason a generator will not start. Propane stores almost indefinitely but delivers somewhat less power from the same engine. Natural gas on standby units avoids storage but depends on the utility line staying up, which is usually reliable in storms but not guaranteed. Our guide to fuel, storage and maintenance goes through the options.
Connecting to the house: do not improvise
How the generator is connected to the home is as important as which one you buy. Backfeeding a house by plugging a generator into a wall outlet, using a “suicide cord” or similar improvised connection, is illegal in many places and can kill utility workers and neighbors. The proper methods, a transfer switch or an interlock and inlet, must be installed by a licensed electrician in line with local code. We do not give wiring instructions. Our article on transfer switches and safe hookup explains what the electrician does and what to ask.
Do you need a generator at all?
Sometimes the answer is no, or not yet. For a few hours of lights, phones and internet, a portable power station, a large battery with outlets, can be quieter, safer to use indoors and maintenance-free. We compare them in portable power stations. A power station will not run a furnace for days, but for many short outages it is the simplest tool.
Holiday sales and winter timing
Generators sell out when storms are forecast, and prices are least favorable then. Holiday and late-season sales can be a good moment to buy, but compare models by output, fuel, run time and warranty, not by the discount. Check what is included, such as wheel kits, covers and fuel, and the reputation of the seller’s service network. Buy early, run the machine once under load while the weather is calm and keep the manual with it.
The short version
Choose a conventional portable for the lowest price per watt and occasional outages, an inverter for quiet and clean power at lower loads and a standby unit when convenience and long outages justify the cost. Whatever you pick, never run it indoors, plan the hookup with an electrician and treat fuel as part of the purchase. The best generator is the one that is ready and safe on the night you need it.
Frequently asked questions
Can I run a generator in the garage with the door open?
No. Carbon monoxide builds up even with the door open. A portable generator belongs outdoors, away from windows, doors and vents.
Do I need a transfer switch?
If you want to power the house wiring rather than run extension cords, yes, installed by a licensed electrician under local code.
Is a bigger generator always better?
No. An oversized unit costs more to buy and run. Size it to a load list, with a margin.
