When the power goes out on the Gulf Coast, most homes fall back on one of three things. Some have a portable generator in the garage, some have a standby generator wired into the house, and a growing number have a battery on the wall. Each one keeps something running. They get there in very different ways.
How each one works
A portable generator is a gas engine on a frame. You roll it outside, fill it with fuel, start it and run extension cords or a transfer cord into the house. It runs as long as there's gas in the tank and someone to refill it.
A whole house standby generator is bolted to a pad next to the house and wired into your electrical panel. It usually runs on natural gas or propane and starts on its own when the grid drops.
A home battery mounts on a wall in the garage or outside, close to the electrical panel. It stays charged from the grid, or from solar panels if you have them, and switches the house over to stored power when an outage hits. There's no engine and no fuel.
Carbon monoxide
This is the difference that matters most. Generators burn fuel, and the exhaust carries carbon monoxide, which you can't see or smell. The U.S. Consumer Product Safety Commission tells people to run portable generators outdoors only, at least 20 feet from the house, with the exhaust pointed away from windows, doors and vents. It also says a porch or a carport is too close, and that opening windows doesn't make indoor use safe.
That's a hard rule to follow at 2 a.m. in the rain, and the CPSC repeats the warning every year for that reason. A battery doesn't burn anything, so it has no exhaust at all. It can sit in an attached garage.
Fuel during a long outage
A portable generator needs gas every day it runs. Gas stations need power to pump, so when the outage is widespread, some of them can't sell fuel at all. Having enough on hand means keeping cans of gasoline at the house.
A standby generator on a natural gas line avoids most of that, as long as gas service stays on. On propane, it runs as long as the tank holds out.
A battery has a fixed amount of stored energy. When it runs low, it needs the grid or the sun to refill. With solar panels on the roof, it can recharge every day the sun is out, even while the grid is still down.
Starting up and switching over
You have to start a portable generator yourself and move cords around to whatever you want powered. Standby generators and batteries both switch on automatically. A battery usually takes over fast enough that the lights barely flicker, which matters if someone in the house uses a CPAP machine or an oxygen concentrator.
Noise
Generators are loud, and the neighbors hear yours too. A battery is close to silent.
Upkeep
Engines need oil changes, test runs and fresh fuel. A portable generator that sat all summer may not start when you need it. A battery has no engine to service.
How long each one runs
This is where generators have the edge. A standby generator on a natural gas line can run for days without anyone touching it. A battery runs as long as its stored energy lasts, and that depends on its size and on what you're running. Central AC uses far more power than a fridge, lights and Wi-Fi. We go through it in more detail in how long a home battery will run your house.
Pairing a battery with solar panels closes most of that gap, because the panels refill the battery every sunny day.
Which one fits your home
If you want to keep the whole house running for a week straight with no sun, a standby generator on natural gas is hard to beat. If you'd rather have no fuel, no exhaust and no noise, and you want the house to switch over by itself, a battery is the cleaner choice, and it pairs naturally with solar.
The way to know what a battery would cover in your home is to size it from your actual electric use. We do that during a free in-home assessment, using your electric bill.