Add up the items you need to power before making your choice
Power outages are often the collateral damage of severe snow and rain storms and other acts of nature. After you've experienced a few you're more likely to consider getting a generator to keep your home’s electricity humming. But before you buy think about whether you want to power your whole house or if you can get by for a few days with just the basics. Here's what we recommend when it comes to choosing the right generator size.
Generators come in two types: portable and stationary, also called standby. Portables cost less to buy and install, but you’ll need to keep it fueled and maintained yourself. A portable also needs to be wheeled outdoors, started, and connected to what you want to power. A stationary model, by contrast, needs to be professionally installed outdoors, which adds expense, but it starts automatically when power cuts off and also performs its own periodic checks—and displays a warning if it needs service.
What to Know About Wattage
To determine generator size, the easiest way is to add up the wattages of everything in your home you want to power with a generator. But some appliances, such as an air conditioner, refrigerator, and sump pumps, require more wattage (called surge watts) when they’re cycling on. It can also be difficult to gauge how much power certain hard-wired appliances, such as your furnace, require. For these reasons we suggest you consult with an electrician, and select a model with a slightly higher rated wattage that will accommodate additional products you might buy.
Also, figure in a few hundred dollars more to install a transfer switch, which allows easy connections for a portable generator. (Stationary generators often come with one.) This component also keeps utility power from frying the circuits you’re protecting once the power returns—and potentially protects any utility workers who might be working on the line. It also protects your generator.
Our generator buying guide lists what the various wattage ranges of both portable and stationary generators will support..
Get Wise About Size
To figure out what generator size you need, follow these simple guidelines. The larger the generator, the more you're likely to pay.
- Just the basics: Small portable (3,000 to 4,000 watts)
What it powers: Refrigerator, sump pump, several lights, television.
- Basics plus creature comforts: Mid-sized portable or small stationary (5,000 to 8,500 watts)
What it powers: The basics, plus portable heater, computer, heating system, well pump, more lights.
- A larger load: Large portable (10,000 watts)
What it powers: Everything above plus small electric water heater, central air conditioner, electric range.
- The whole house: Large stationary (10,000 to 15,000 watts)
What it powers: Same as large portables, plus clothes washer, electric dryer.
Some Top Performers
Here are some recommended models from testing over 37 models.
- Kohler PRO7.5E, $1,400, a 6,300-watt portable that supplied plenty of power, and cleanly, with less noise than many competing models;
- Generac RS7000E, $900, a 7,000-watt model that performed nearly as well;
- Generac 6237, $2,250 (with transfer switch), a stationary generator that delivers 7,000 watts using natural gas and 8,000 using propane; and
- Kohler 14RESAL, $3,700 (with transfer switch), a larger stationary generator that supplied 12,000 watts using natural gas—and 2,000 more with propane.
Whichever generator size you choose, don’t wait until a major storm is forecast to buy it. In addition to facing a more limited selection, you’ll cheat yourself out of the weeks you need to plan your purchase and get it installed before you can enjoy the protection of a generator that will serve you for years to come.
For more information contact South Shore Generator in Wareham, MA.