Some generators can be more of a hassle than stormy weather

If recent storms and power outages have helped you conclude that life has become too unpredictable not to own a generator, you'll probably be told that the most important consideration is how much wattage you need to keep your household humming. But as Consumer Reports discovered in its recent generator tests, choosing between a portable and a stationary generator also depends on your ability to run and maintain it.

The Ratings of portable and stationary generators we've just posted cover 14 models, and there are pros and cons for each type. Then there's what fits your lifestyle.

Portable models are okay if you can wait from a few minutes to an hour to get back online. Unless you've had fair warning, you'll need to move the generator into place and make sure you have fuel on hand to run it. Not everyone can store gallons of gasoline or multiple 20-pound tanks of propane. (During a storm, you may find roads that are closed and gas stations with pumps that don't work.) And because of safety concerns, not everyone in the household will be able to start the generator or operate the transfer switch. And a portable generator may not be a good choice for someone who works a long way from home and can't get there in time to restore power.

Even though they cost more, there are none of those concerns with a stationary generator. Since it's mounted outdoors, nobody needs to wheel it out of the garage. Fuel isn't an issue because you can get more than 200 hours from a 250-gallon propane tank, and unlimited hours if you have a natural-gas hookup. And in addition to starting up automatically when the power goes out, stationary generators routinely start themselves up to self-diagnose. An arrangement with a local dealer gets you necessary maintenance before a power outage.

We also found issues that are model-specific, such as generators that offer electric start—but no battery (about $50 extra). One portable model is heavy enough that it might as well be a stationary unit; another is lighter, but wheels are $150 extra. And some models, including one stationary unit, provided power that was uneven or low-voltage, which makes motorized appliances and sensitive electrics run hotter.

—Ed Perratore