Blackouts are nothing new, but major storms over the past two years have hammered home the importance of electrical power. Last fall Hurricane Sandy pummeled the Northeast, disrupting power for more than 8 million customers and leaving families homeless as temperatures dropped. Sandy blew in just 12 months after a historically destructive snowstorm hit the same region. In fact, 2011 was among the nation’s worst years on record for grid-disabling natural disasters, with power interruptions longer than 24 hours affecting 21 million customers. Sadly, Sandy promised a second consecutive year of dire power-outage numbers.

While big-box stores quickly sold out of portable gasoline-powered generators after the storm, Generac, Briggs & Stratton, and Kohler announced that they would ramp up production of standby generators, which can energize a home nonstop for days. But these sophisticated machines also can cost more than $20,000 installed, and some are the size of a Fiat 500. Here are six points to help you decide whether they’re worth the investment.

1. What They Are

Standby generators offer a steadfast solution to extended outages. Unlike portable generators, they’re installed permanently on a concrete pad in your yard and will provide uninterrupted backup for days. That’s because they’re connected directly to your home’s electrical panel and powered by an external fuel supply, such as natural gas, liquid propane, or diesel. Smaller, air-cooled essential-circuit units (below) are slightly larger than portable generators and can energize just a few circuits at a time. Larger, liquid-cooled whole-house systems will do just as their name suggests—they’ll comfortably power an entire home.

2. How They Work

The brains behind the operation is an automatic transfer switch that disconnects you from your utility after detecting an interruption in service. Once your home is safely off the grid, the switch starts up the generator before transferring its power to the home’s electrical panel. At the heart of the system is an internal combustion engine, which is usually fueled by the local natural gas supply. Where natural gas isn’t available, liquid propane or diesel stored in a large tank nearby can be used. Keep in mind these systems rely on a finite amount of fuel that could run dry if storm damage prevents delivery or increased demand hampers supply.

When municipal power resumes, the switch shuts down the generator and reconnects your house to the grid. This seamless operation makes standby generators ideal for families with small children, as well as those needing uninterrupted use of electric-powered medical equipment. They’re also crucial for anyone running a home business. The transfer switch acts as a safety mechanism too: It prevents back-feeding electricity to the grid, a potentially lethal practice that can start fires and harm utility workers attempting to restore your neighborhood’s power.

3. Installation Drawbacks

Cities often have noise ordinances restricting the installation of generators. A machine may be rated at 62 decibels, but that’s often measured at 25 feet. What does that sound like? Imagine a neighbor idling a Harley—tolerable in a rural environment but unacceptable in a tight city lot. Additionally, most building codes require generators to be at least 5 feet from a house opening and 5 feet from flammable materials, making urban installations tricky. Fuel-tank placement is almost always restricted, especially near parking lots and schools. Read More