It's the force behind your heater, your lights, your TV and computer. It's your power supply, and if you take it for granted, you might be left in the dark.

When the lights go out, food also starts to spoil and heat and cold shut off—often in extreme temperatures, creating a health concern for children and the elderly. And what's worse, sump pumps in basements and crawl spaces won't operate when they are most needed to discharge storm water, which can lead to thousands of dollars of damage.

Being without power for few hours is a nuisance. Not having power for days, weeks or even longer can be both costly and dangerous.

The good news is that an automatic standby generator can return your home to full power within seconds. It works even when you're not home. In contrast to a portable generator, an automatic standby generator senses an outage and begins to produce power immediately. There are no extension cords to plug in, gas tanks to fill or switches to flip.

Even better news is that although automatic standby generators were reserved almost exclusively for hospitals, television and radio stations or the very wealthy, advances in technology have made automatic standby generators more affordable and available to mainstream America.

Automatic standby generators rank high on Remodeling Magazine's annual "Cost vs. Value Report," which measures the popularity and return on investment for home improvement projects. Depending on the number of essential circuits required, homes can be protected for about $2,000 plus installation with an 8-kilowatt unit.

HOW IT WORKS

Unlike a portable generator, which can be dangerous and difficult to operate, an automatic standby generator operates on your LP gas or natural gas supply. The generator monitors incoming voltage from the utility line and when power is interrupted, it senses a problem and transfers to standby power.

Within seconds, the generator supplies electricity to the essential circuits you've chosen. When utility voltage returns, the electrical load is transferred back to the utility line.

Sound pretty simple? It is. There are no levers to pull to activate power, no pull cords to yank to start a generator motor and no potentially harmful carbon monoxide fumes due to the fact that the unit is permanently installed outdoors in a safe and secure location. In fact, most automatic standby generators look like the compressor for a central air conditioning system. With a little creative landscaping, you'll never know it's there.

FINDING A FIT

If you think an automatic standby generator might be for you, the first step is to determine what systems in your home you need or want to have powered during an outage. Although you can back-up your entire home, it is typically more cost efficient to back-up essential circuits, which can include some lighting (kitchen, bathroom, basement), a sump pump, a refrigerator and/or freezer, a television, a computer, a microwave, a garage circuit (to operate an automatic door opener) and a security system.

You may also opt to include a home office, an electric water heater (or the electrical supply for ignition for a tankless or hybrid water heater), and a well or irrigation pump.

The next step is to determine the amount of power (in watts) that each of the desired systems requires. Wattage may be listed on the product—if it's listed in amps, multiply by 120. An electrical circuit is about 1650 Watts, a refrigerator 725, a furnace, 750, a water heater 4500-5500. To calculate lights, add the wattage of bulbs.

Then add those numbers to establish the total amount of power needed, which, in turn, will determine the size of the generator needed in kilowatts (kW)—each kilowatt is 1,000 watts. Most residential automatic standby generators range in size from 8kW to 16kW (though there are smaller and larger units) and retail from between $2,000 to $3,500 plus installation.

Leading brands have an "exercise" mode, which will automatically start the generator motor on a regular predetermined schedule—typically weekly—to make sure the device is operating properly. Failure will result in a warning light or alarm, which will allow for necessary maintenance or repairs. Beyond regular "exercising," the oil level should be checked regularly and other maintenance performed as suggested by the manufacturer.

For more information on automatic standby generators, visit www.guardiangenerators.com.