How to Select the Right Commercial Grade Generator

Commercial Grade Generators

Power your business with the right commercial electric generators from Home Depot Pro. We carry a variety of portable and standby generators built for use by businesses like yours. We also make choosing the best generator for your job easy with our commercial generator buying guide, helpful selection tips and always-available industry experts.

Types of Generators

Portable vs. Standby Generators

The best generators for business come in two main options: portable or standby. Portable generators provide convenient power when and where you need it. They are easy to transport between jobsites, supply a continuous amount of power and come in a range of modest to moderate wattage options. Standby generators typically offer more power, ranging from moderate to substantial wattage options, but are not easily transported. They also come with various efficiency features, making standby generators ideal sources of reliable backup power for businesses.

Inverter Generators

Inverter generators are the latest advancement in fuel-efficient, portable generators. They come in a variety of wattage options with most in the middle ranges. That makes inverter generators an efficient option for convenient, on-the-job power.

Calculating Power Requirements*

Choose the best commercial generator for your business needs by calculating your power requirements. To do this, first 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 wattages, 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, large 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, however, 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.

*Note: All power requirements on the included table 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.

EquipmentRunning WattageStarting Wattage
60-Watt Light Bulbs60W-
Floodlights500W-
Quartz Halogen Work Lights1,000W-
Wireless Power Tool Battery Chargers330W 
1/3 hp Sump Pumps800W1300W
Reciprocating Saws960W-
5.4 Amp Electric Drills600W900W
Circular Saws1,400W2,300W
Belt Sanders1,400W2,400W
Angle Grinders1,800W4,000W
1 hp Air Compressors1,600W4,500W
Band Saws1,200W2,400W
Miter Saws1,800W3,400W
Table Saws1,800W3,400W
5 hp Wet & Dry Vacuums1,000W-
1.25 hp Blower Fans950W-
Pressure Washers1,200W3,600W
Cell Phone Chargers10W-
Personal Computers800W-
Printers900W-
20-Inch Box Fans200W-
Radio or CD Players100W-

Selecting Features

Not all generators are created equal. Get the most out of your investments by making sure your generators have the features your job demands.

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.

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.

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.

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.

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.

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.

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.

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.