Home backup power, one layer at a time

Start by making a list. Ready.gov suggests taking an inventory of everything in your home that runs on electricity, then planning batteries and other backup sources for the items you truly need. That short list decides how much power you need.

Know your numbers

Two figures do most of the work. Watts tell you how hard a device pulls at any moment. Watt-hours (Wh) tell you how much energy a battery holds. A device label or its charger usually lists the watts.

Our wattage calculator does this math for a whole list at once, including generator sizing, or you can run it by hand for each item. Phones and lights barely dent a battery. Anything that makes heat, like a space heater, kettle or hair dryer, drains one fast and is better left for when the grid is back.

Open the wattage calculator

Build it in four layers

1. Light for every personReady.gov recommends flashlights for every household member. A headlamp keeps both hands free, and a lantern lights a whole room.
2. Phone powerA charged power bank keeps your phone ready for alerts, maps and family calls. Charge it now and top it up every few months.
3. A portable power stationA rechargeable battery with outlets that runs quietly and gives off no exhaust, so it can sit indoors. Sized right, it covers a router, lamps, a fan and a laptop.
4. A generator, outdoors onlyFor bigger loads like a refrigerator, a fuel generator does the heavy lifting. It also brings the strictest safety rules, listed below.

Medical devices come first

If anyone in your home relies on a powered medical device or refrigerated medicine, put that at the top of the list. Ready.gov advises talking with your medical provider about an outage plan, including how long medicine can be stored at higher temperatures. Ask the device maker how many watts it draws, then size your battery with room to spare. It also helps to tell your electric utility that someone at home depends on powered medical equipment, and to ask whether it keeps a list of those customers.

Generator rules worth memorizing

• Run generators and store fuel outdoors only, at least 20 feet from windows, doors and vents, and away from attached garages (Ready.gov, CDC, CPSC). Never run one inside a home or garage, even with doors and windows open.
• Never plug a generator into a wall outlet. To power household circuits, have a licensed electrician install a transfer switch or an interlock and inlet.
• Put battery-backed carbon monoxide alarms on every level of the home. CO has no color and no smell.
• Keep the generator dry and out of rain or floodwater.
• Connect appliances with heavy-duty extension cords rated for the load.
• Let the engine cool before you refuel.
• Follow the manufacturer’s instructions for setup and maintenance.

Keep going

Sources: Ready.gov, Power Outages (inventory, flashlights, medical needs, food storage and generator safety); CDC, Carbon Monoxide Poisoning Basics; CPSC, Carbon Monoxide Information Center (generators at least 20 feet from the home). Product details are from each Amazon listing as of November 14, 2026, and the First Alert CO710 product page.