Generator Buyer's Guide

We've all experienced downpours, blizzards or tropical storms that have caused the occasional power outage. Generators can ensure that such events don't leave you in the dark. Home generators supply your house or RV with power during prolonged outages, providing your family with amenities such as heat and a running refrigerator. Also, portable units bring at-home comfort and convenience to camping trips and other outdoor excursions by running heaters, lights and power tools at locations miles away from electrical outlets.
Before choosing the right generator for your needs, there are several factors to consider.

Mobility and Weight

Relative to their size, generators aren't lightweight. Some portable generators, especially larger models, feature wheels for convenience. These are best handled by at least two able-bodied people when lifting from truck boxes or trailer beds.

Compact generators are lighter, though this is generally at the expense of power and fuel capacity. It's important to remember that the weights listed in generator specifications do not include fuel.

Power Requirements

When determining generator power requirements, consider the appliances with the highest power needs first. The power required to start these applications will determine the rated power of the generator you should choose for your needs.
Peak Power
Peak power is the maximum power a device can supply at a specified wattage for a brief amount of time (usually only a few seconds). Peak power is most often encountered when an appliance powered by an electric motor is started because motors use substantially more energy at startup than to run once they’ve been turned on.

Resistive Power vs. Reactive Power

Resistive appliances, like light bulbs, use the same amount of power from when they are turned on until they are shut off. Resistive appliances do not usually operate with an electric motor.

Reactive appliances have a peak-power requirement. Because of this, they need the added power of an electric motor to start. We've all seen lights dim when a refrigerator or dryer turns on; these are both examples of reactive appliances.

Determining Wattage

The generator requirement of any given appliance can be determined by using this simple formula: Volts x Amps = Watts.

With this formula, you only need to know two of the variables to calculate the third.

For example, you may want a generator to power a 120-volt coffee maker that requires 6 amps of current. By multiplying the given variables (120 volts x 6 amps), you are easily able to determine that operating this coffee maker will require 720 watts of power.

A generator should never be operated at its maximum power output for more than 30 minutes. Rated power, or 90% of maximum power, is a more reliable measure of safe generator use. Exceeding this specified power rating on any device by more than the marginal level of safety that’s been set by the manufacturer can cause operating temperatures to reach unsafe levels and result in damage to the device.

Recreation Wattage Estimation Guide
Application Approximate Starting Wattage Approximate Running Wattage
RV Air Conditioner
11,000 BTU 1600 1010
13,500 BTU 2800 1800
15,000 BTU 3300 2000
RV Refrigerator 600 180
Blender 850 400
Electric Grill (tabletop) 1650 1650
Slow Cooker 170-270 170-270
Radiant Heater 1300 1300
Fan (portable) 120 40
Satellite Reciever 250 250
DVD Player 350 350


Home Wattage Estimation Guide
Application Approximate Starting Wattage Approximate Running Wattage
Refrigerator or Freezer
(Energy Star)
1200 132-192
Microwave Oven
650 watts 1000 1000
800 watts 1300 1300
1000 watts 1500 1500
Incandescent Lights as indicated on bulb
(i.e. 60W)
as indicated on bulb
(i.e. 60W)
Tube type 300 300
Flat Screen (20") 120 120
Flat Screen (46") 190 190
Coffee Maker (4 cup) 600 600
Dishwasher (Cool Dry) 540 216
Electric Fry Pan 1500 1500
Automatic Washer 1200 1200
Radio 50-200 50-200
Window Air Conditioner
(10,000 BTU)
2200 1500
Laptop 200-250 200-250
Desktop 600-800 600-800
Monitor (LDC style) 30 30
Printer 400-600 400-600
Garage Door Opener 1420 720
Air Compressor
1/2 hp 1600 975
1 hp 4500 1600

Inverter Generators

Inverter generators are ideal for powering sensitive electronics such as computers, televisions, cell phones and tablets. These units use the technologies of both generators and inverters to output AC current, convert it to DC current and then invert it back to clean AC power that will charge sensitive devices.

Making the Wise Choice

Whether you’re in need of a portable generator to supply power at the campsite, or a large home generator to use as an alternate power source when the electricity goes out, it’s important to keep all of these factors in mind when making a purchasing decision. Knowing the wattage required, factoring peak power appliances, as well as determining the generator size and weight that best fit your needs, will not only allow you to choose a generator with confidence, it will also make life easier at home, work, in the RV or around camp.