Blackouts are nothing new, but major storms over the past two years have hammered home the importance of electrical
power. A standby generator can ensure your home remains energized 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.
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.
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.
4. They’re Not For Rookies
Hire a professional to assess not only your load needs (see No. 5), but also the logistics of
installing a generator in your home. If you’re planning on connecting to your local natural gas system, you’ll need
a high-pressure, high-volume line. Most generators require gas supplied at 5 to 7 inches of water-column pressure,
which isn’t available in some towns.
Installing a standby generator is no DIY project, either. It requires advanced electrical and
plumbing skills, as well as knowledge of local building codes. You’ll also need permits before you start and
inspections when you’re done. Because of these complexities, professional installations can sometimes triple the
cost of a generator.
5. They’re Big and You need one
The higher the generator’s capacity, the more circuits it can power at once. However, the size of
your generator should be determined by your needs in an emergency, temporary situation—you’re not looking to power
each and every appliance and gadget during desperate times. The chart below will give you some idea of how much
electrical capacity you’ll need, though you should consult a professional for an accurate load analysis. He or she
will calculate the combined load of the devices you intend to run simultaneously while also considering the starting
wattages of motor-driven appliances such as refrigerators and AC units.
Many homeowners choose a generator based on what they can afford, and with good reason. A quality
essential-circuit system starts at around $3000, and that’s not including installation. Then there’s the price of
fuel: A fully loaded 7-kw unit consumes around 140 cubic feet of natural gas per hour. Based on average rates
nationwide this summer, that’s $2.23 per hour. Expect at least double that with a 22-kw unit. Keep in mind
that large, whole-house systems can add significant value to a home.
6. We Maintain them for You
Like cars, standby generators run nonstop for many hours, so they have to be maintained as if they
were, well, cars. Generally, bigger units require more care.
“After 24 to 48 hours of continuous use, get it serviced,” installer Pat Porzio says. “After around
10 days, have a professional change the oil and the filter.”
Your generator will stay healthy through a lifetime of outages if you check the engine oil daily
during use, run it at no more than 75 percent of its rated capacity, replace overworked or deformed motor brushes,
and avoid starting or stopping it under load whenever possible.