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Commercial Generator Buying Guide

How to Select the Right Commercial-Grade Generator

Commercial-Grade Generators

Power your business anywhere. Our portable generators are built for the jobsite, are easy to transport and provide a continuous supply of power. They also come in a wide range of wattage options. Our portable inverter generators offer similar capabilities but with reduced noise. For your more permanent needs, we offer standby generators that are installed to provide backup power to a residence or facility in the case of a power outage.

Calculating Power Requirements*

Choose the best commercial generator by calculating your power requirements first. To do this, add the total running wattage of the equipment you need to operate. Then, add that total with your equipment’s single-highest starting wattage. If you do not know the wattage, calculate it by multiplying volts and amps.

Starting Wattage & Surge

Starting wattage is the extra amount of power your equipment needs to start. Surge wattage represents the maximum amount of wattage your generator can produce. Because tools with motors or compressors, such as pressure washers and air compressors, require significant starting power, starting and surge wattage must be considered when choosing your generator. Overloading can damage your equipment and the generator. If you do not know the starting wattage of your equipment, you can safely estimate it at 3 times the running wattage.

Think Economically

Generator prices increase exponentially with size. You may be able to save more money by purchasing multiple, smaller generators instead of a single, larger generator. Large generators are great options when your job demands a lot of wattage or a constant rate of flow in one location. If your job calls for the same total wattage spread across multiple locations, you may be able to get more out of your investment with two or more smaller generators. Having multiple generators can also reduce cordage requirements, limit amperage loss and help equipment last longer.

*All power requirements are general examples and should not be used to calculate specific requirements. Always refer to your manufacturer-provided power requirements, which are often found in the accompanied user manuals. Also, please note generators should not be used at their maximum capacity for long periods of time. Maintaining a usage of no more than 90% capacity is recommended. Always locate generators within a well-ventilated area.

Equipment Running Wattage Starting Wattage

60-Watt Light Bulbs






Quartz Halogen Work Lights



Wireless Power Tool Battery Chargers



1/3 hp Sump Pumps



Reciprocating Saws



5.4 Amp Electric Drills



Circular Saws



Belt Sanders



Angle Grinders



1 hp Air Compressors



Band Saws



Miter Saws



Table Saws



5 hp Wet & Dry Vacuums



1.25 hp Blower Fans



Pressure Washers



Cell Phone Chargers



Personal Computers






20-Inch Box Fans



Radio or CD Players




Shop All Generators

Selecting Features

Multiple Outlets

Most generators come with a few outlets, but your job may demand more. Be selective. Splitters can help increase the number of standard outlets, but those must be used appropriately.

Outlet Configurations

Outlet configurations vary between generators and can include types like AC, DC and twist locks. Match the NEMA labels on your equipment with the generators’ labels to ensure compatibility.

Alternative Fuels

Generators typically run on gasoline, propane, natural gas or diesel, but units that accept multiple fuel types are available. Select the most convenient and cost-effective option for your use.

Electric Starts

Electric starts help turn generators on easily. These features depend on a battery, so check the requirements. Batteries may not be included. You may also want an optional pull-start.

Auto-Idle Controls

Auto-idle controls increase efficiency by regulating generator engines when they are not in use. This extends run times when jobs require readily available, but not constant, electricity.

Fuel Gauges

Some generators have fuel gauges while others do not. These are not typically necessary for jobs, but they are great features if your staff can benefit from checking fuel levels visually.

Low Oil Shutdowns

Available on most generators and nearly standard on all standby generators, low oil shutdowns turn engines off automatically when their oil drops below minimum required levels.

Hour Meters

Hour meters track and record a generator’s total running time. Knowing exactly how long a generator has run can help you efficiently manage its maintenance and improve its longevity.