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Backing Up Your Essentials

Portable Generators in an Emergency

Backing up your home may not mean backing up everything. A portable generator is an excellent way to protect your most essential lights and appliances. This is especially important in emergency situations where you may not have time to purchase a generator that will back up your whole home. The most important thing is covering your key circuits that will help you survive the outage.

We know you love your home and, in an ideal world, you would cover all of it, but that may not be possible on short notice. Truth be told—some rooms are simply more important than others during an extended outage. The kitchen is one such room, and potentially your living room, where your family can congregate. However, the upstairs spare bedroom that is used once a year when family comes to visit probably falls into the “nonessential” category. For that reason, you can choose a backup power solution based upon protecting only those critical rooms—and their lights and appliances—during a power outage. Investing in a portable generator is a particularly cost-effective solution to provide power. Portable generators are typically not large enough to back up your entire home, but they can go a long way during an emergency.

When choosing a portable generator, the first order of business is to do a little math (we apologize in advance). Once you’ve identified those lights and appliances you can’t live without, start adding up how much power they require in watts. For things like lights, it’s a pretty easy question to answer, because light bulbs are identified by their wattage. A microwave oven is another appliance typically identified by its wattage. But other appliances might mean doing some additional calculations (again, we’re sorry). Fortunately, they’re not difficult.

Determining how many watts an appliance uses requires multiplying the volts it requires times the amps of current that flow through it.

Watts = Volts x Amps.
Thus, if your appliance draws 20 amps of current from a 120-volt outlet, it uses 2400 watts (20 x 120) of electricity.

Once you have your list, add all of it up to get the total watts you need to back up those appliances.


Then it’s a simple matter of finding a portable generator that delivers at least that amount of power. It’s important not to use a generator too small for the job. Overloading a portable generator can damage it, leading to costly repairs or worse — turning your several-hundred-dollar investment into a rather large and heavy doorstop.

Two Important Things to Think About:

  • As you tally up your power needs, it’s important to consider the additional power needed to start motors in appliances that have them, such as refrigerators or freezers. Motors require a very brief (a second or two) surge of electricity to start the motor — a surge that can exceed its running watts by as much as three times. So, for appliances like that, it’s best to multiply their running watts by a factor of three.

For example, if your refrigerator needs 700 watts of electricity for normal operation, you should account for 2100 watts to ensure you have enough power to start its motor. This practice will give you a buffer for that momentary surge of electricity, which incidentally is called “surge watts.” Many portable generators can deliver a brief surge of power above their rated output, but again, it’s better to be safe — especially if you are powering several appliances with motors.

  • Portable generators cannot power hard-wired appliances, like a furnace or well pump, without a transfer switch. For that reason, when considering a portable generator you should limit yourself to those appliances you can plug into an extension cord. You will operate your portable generator outside your home and run extension cords through doors or windows to your appliances.

Portable Power ✓

To learn how to choose the best portable generator for your needs, download our "How to Choose a Portable Generator" guide.