Pick a generator that fits your house, then run it safely

01Portable, inverter, or standby — what each one is for

Fuel-burning generators fall into three broad groups. They overlap a little, but each is built around a different job, and buying the wrong type is the most common expensive mistake.

02Add up what you actually need to run

Sizing comes down to two numbers. Running watts is what a device draws once it's going. Starting watts is the brief surge a motor or compressor needs to get moving — and it's often two to three times higher. Your generator has to cover all your running loads plus the single biggest startup surge.

1. List the must-haves

   Think in terms of a long outage, not a cozy evening. Refrigerator, freezer, sump pump, furnace blower, well pump, a few lights, phone charging, and any medical equipment.

2. Find each device's wattage

   Check the nameplate sticker, or the manual. If you only see amps, multiply by the voltage (120V or 240V) for an approximate watt figure.

3. Total the running watts

   Add up everything you plan to run at the same time. Leave yourself a cushion of about 20 percent so the generator isn't running flat-out for days.

4. Add the largest starting surge

   Only one motor usually starts at a time, so add the biggest single surge — often the well pump, sump pump, or a window AC — on top of your running total.

5. Stagger the big loads

   Start motors one at a time and let each settle before switching on the next. That alone lets a mid-size generator handle a surprising amount.

03Get power into the house the right way

There are really only two safe ways to use a portable generator — heavy-duty extension cords run to individual appliances, or a properly installed transfer switch or interlock that feeds selected circuits. Anything else risks the people working on the lines and your own wiring.

1. Pick your circuits

   Work with the electrician to choose six to ten circuits — kitchen fridge, sump pump, furnace, a few lights — that match your generator's output.

2. Match the inlet and cord

   The inlet box and generator cord need matching plugs and amperage, typically a 30-amp or 50-amp twist-lock. Confirm before you buy either.

3. Practice the switchover

   Run through the sequence once in daylight — start the generator, plug in, flip the switches — so you're not learning it by flashlight.

04Store fuel so it's ready when you need it

In a wide-area outage, gas stations often can't pump. The fuel you have on hand when the storm hits may be all you get for several days, so plan around it.

1. Know your burn rate

   Check the manual for run time at half load. Multiply out how many gallons, or how many propane tanks, a three-day outage would take.

2. Treat gasoline and rotate it

   Untreated gas can start to break down within a few months. Add fuel stabilizer when you fill the cans, and pour older fuel into your car so the stock stays fresh.

3. Store it outside the living space

   Keep approved containers in a detached shed or well-ventilated area away from the water heater, furnace, and any flame. Check local rules on how much you're allowed to keep.

4. Keep propane tanks upright and outdoors

   Never store or refill propane tanks indoors or in a garage. A few spare filled cylinders is the simplest long-term fuel reserve.

5. Run the generator monthly

   Start it and put it under some load for 15–20 minutes. A machine that sat all year with old gas in the carburetor is the one that won't start.

05Carbon monoxide — the rules that keep people alive

Generator exhaust contains carbon monoxide, which you can't see or smell. Poisonings spike after nearly every major storm, and many happen because a generator was run somewhere that felt sheltered — a garage, a basement, a porch.

• Run it outdoors only, at least 20 feet from the house, with the exhaust pointed away
• Never in a garage, basement, crawlspace, shed, or enclosed porch — even with doors open
• Keep it away from your neighbors' windows and air intakes too
• Use a generator tent or canopy designed for wet weather instead of moving it closer to shelter
• Install battery-powered or battery-backup CO alarms on every level and near bedrooms
• Know the symptoms: headache, dizziness, nausea, confusion — get to fresh air and call 911

If a fuel generator doesn't suit your home — you're in an apartment, you can't store fuel, or you need power indoors — a battery power station may be the better fit. Our backup power guide covers those options.