As Winter Approaches, Generating Answers

Inclement weather also increases the risk of electrical shock from connecting extension cords to a wet generator. Most residential portable generators -- unlike their military counterparts -- are not designed for rain exposure, Kelly said. People who splurge on a high-performance $1,500 generator may skimp on an extension cord, not knowing that thin wiring increases the risk of overload or fire, Kelly said.

During a power outage, some people attempt to re-energize their home's electrical wiring by directly connecting their generator to the electrical outlet dedicated to their clothes dryer. These "suicide connections" are aptly named, Rubala warned.

Consumer Reports in October found that most portable generators fall substantially short of their advertised claims for power and running time on a single tank of gasoline. Big portable generators are gas guzzlers. During a 48-hour outage that knocks local service stations offline, these units will consume 40 or more gallons of gasoline, making at-home fuel storage a problem, Rubala said. The relatively short shelf life of gasoline requires periodically replacing stored gasoline.

With ample fuel, most portable generators can be kept running for days, with occasional breaks for checking and changing oil. Some manufacturers, however, warn against long run cycles.

Consumer Reports also found that most portable units deliver inconsistent voltage, which exposes unshielded electronics to potentially damaging power surges. Using a good surge suppressor will reduce the risk.

Portable generators produce carbon monoxide and should not be operated indoors, in garages (even with the doors open), or in confined spaces outside.

Limitations aside, "a 5,000- to 7,000-watt unit can get you through a three- or four-day power outage very easily," Rubala said, "but you have to be willing to work with it." The rule is simple: Do not overload the generator. If you need to operate energy-intensive devices, rotate them in shifts.

Stationary Generators

Paul Offutt discovered in 2003 that his new 5.5-kilowatt portable generator was too anemic to power the one-horsepower pump inside his 550-feet-deep well at his Middletown, Md., home. After being left "dead in the water" several times, he learned that motorized items -- pumps, refrigerators and heating and cooling systems especially -- become momentary energy hogs when they start. A one-third-horsepower sump pump may need just 1 kilowatt to run, but 2 kilowatts to start up.

In 2004, Offutt spent about $5,000 for a 15.5-kilowatt stationary unit. He enjoys the convenience, self-sufficiency and peace of mind, he said. He expects to recoup most of his investment when he sells his house.

Big, beefy stationary generators can crank out 10 to 60 kilowatts -- enough to keep a busy house running indefinitely, provided there's an uninterrupted supply of natural gas or propane. Consumer Reports rated the overall performance of stationary units much higher than that of portables.

Stationary generators are costly. However, small units aren't always the best value, Kelly said, as they can require higher relative installation costs. Kelly quoted a $6,000 to $9,000 installed price for a 16-kilowatt Generac unit, depending on location and complexity of installation.

"Sometimes it's cheaper to buy a bigger generator than to install a smaller unit that requires more elaborate installation," he said. "You can get double the wattage for a minor additional cost and it's going to last the life of the home."

The largest residential generator unit Kelly has installed was a 250-kilowatt monster with a $45,000 price tag. "It was for an extremely large mansion with elevators," he said.

Building codes require stationary units to be installed by a licensed electrician and plumber.

When a sensor detects a power outage, a transfer switch starts the generator within seconds, sending current to designated, priority household items. Should the utility's power resume seconds later, the generator shuts down either immediately or after a preset "exercise program," Kelly said.

The better stationary models are quiet enough to comply with all but the strictest noise rules, Rubala said. Routine maintenance is typically limited to checking and changing oil.

In 2004, Maryland home builder Mark Lancaster had a 25-kilowatt propane-fired generator installed next to his 7,800-square-foot residence in Frederick County. A big generator made sense, he said, because his house is computer-controlled and future buyers will expect reliable power.

The backup unit provides sufficient power for refrigeration, heat, primary lights, home office, televisions and more. "Most of the basement lights are not wired in," Lancaster said. "I don't think I'll be running downstairs to play pool [during a power outage]. That's kind of over the top."

Battery-Based Systems

Whole-house battery systems are silent, emission- and maintenance-free, and ideal for townhouses, said Fred Banner of Banner Power Co. in Rockville, which sells such systems. These units are not typically installed in apartments or condominiums because of limitations with space and access to electrical panels, he said.

His company's battery units deliver 4.5 to 18 kilowatts. The top seller -- a 12-kilowatt model -- costs about $20,000 installed, has a footprint the size of a four-drawer file cabinet turned horizontally, carries a five-year warranty and is solar compatible. This system will supply critical needs "for one to two days," he said.

For people concerned about longer power outages, his firm also sells a 12-kilowatt gasoline-powered generator (with voltage regulator) that can recharge the drained batteries in about one hour, he said. Banner said his own 8-kilowatt system at home powers his critical needs and has plenty of reserve.

Regardless of the backup system chosen, Banner said people should make sure it is engineered to support the load connected to it. People hoping for a whole-house solution may purchase a medium-size stationary generator only to learn it does not have the capacity to keep their central air conditioning going.

There are also portable battery units suitable for condominium and apartment use. Xantrex Technology Inc. sells in Canada its PowerHub 1800, which delivers enough power to run a refrigerator or microwave individually, or multiple loads simultaneously, said Xantrex's Grant Dunbar. The product, scheduled for a 2007 release in the United States, has a modular design that allows the easy addition of car or marine batteries, for additional run time.

Kelly isn't convinced on batteries, for most applications. "If the outage lasts a day or two," he said, "you're right back where you started from."