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Things to Know Before You Buy

Buying a generator can be a daunting process. However, you can take control by being informed and getting organized. Here is a simple checklist to use to help in choosing the correct generator to protect your home and family.

• Determine wattage needs. Determine how much power you need for the items you care about. For help, try our power selection worksheet. If you decide to purchase a portable generator, don't forget you will also need a transfer switch to safely power the circuits in your home.

• Decide: Standby or portable? Considering your budget, convenience, and power needs, choose which type of generator fits your needs.

• Consider included items and services. Does the generator come with warranty or maintenance package? What about a power cord, oil, wheels, and funnel? How much more will it cost for installation by a qualified professional? Will you need an accessory like a cover for protection from the elements or a transfer switch?

• Establish your budget. Generator prices fall across a wide range, so determining how much you’d like to spend is important.

• Check out special features. Generators come with an array of features to make use easier and safer. Learn about what to look for when picking the best set of features for you.

• Learn more. Check out our Glossary of Terms and Frequently Asked Questions (FAQs) to learn more about the ins and outs of generators.

Understanding Your Wattage & Runtime Needs

There are two basic power measurements for generators: starting watts (also known as startup power, max watts, or peak power) and continuous or running watts. Starting wattage is required for appliances at startup or when they are running at their highest levels of power consumption. Continuous power is the wattage required for operation of those appliances under normal load. Both are measured in wattage.

Wattage: Below is a chart that will give you an idea of how much power different appliance require.

See full How-To-Choose Table

Total your equipment’s power requirement from the chart above to determine the necessary running watts your unit will have to have. Then, multiply the total wattage requirements of any equipment with a motor by two* to determine the amount of starting watts required.

For more help, download our worksheet

Runtime: Generators will callout how much run time they can get at 25% or 50% load. This represents about how much time they will run with a full fuel tank, using that percentage of their total power. If you think you will need more runtime, or if you are using your generator for emergency situations where you cannot predict how long you will need it to run for, consider purchasing one with a larger tank.

Types of Generators

Generators come in two basic types: standby and portable. There also are inverters, which are not generators but may meet your needs. The source of backup power you ultimately choose will be determined by many factors, including your power requirements.

Standby generator
Standby Generators:

These generators typically run between 7,000-20,000 watts to offer 24/7 blackout protection. They automatically provide power to your home until the outage is over. Standby generators are professionally installed and draw their fuel supply from an existing line of natural gas or propane. Home standby generators can cost between $1,800-$40,000 and require professional installation, often with a permit.

The number of circuits to which a standby generator can provide power--and the number of appliances you can run on those circuits--is determined by the power capacity of the generator.

Standby generators are typically fully enclosed and vary in size. Check the dimensions carefully. A standby model may cost as little as $1,500 or as much as $15,000 or more--the greater the power capacity, the higher the cost.

Portable generator
Portable Generators:

Portable generators can be used to supply limited emergency storm power, jobsite power or power leisure activities like camping and tailgating. It is important to consider wattage, runtime, size and mobility when choosing which portable generator is right for you. Portable generators range in power from 1,000-10,000 watts and in price from $100-$3,000 depending on special feature and wattage capabilities.


Inverter generators are ideal for tailgating, camping, boating or RV’ing. These generators are smaller in wattage capabilities, typically ranging from 800-3,000 watts; but are desirable for their clean power, quietness, efficiency and size. Inverter generators can cost anywhere from $200-$3,000.

Common Uses

What you plan to use your generator for will greatly impact which generator you decide to purchase.

Storm & Emergency Power: If you’re primarily buying a generator for storm and emergency power, you will need to decide what electronics and appliances are important for you to power. Do you need to back up your entire house, a few essential circuits or just a couple of appliances? If you need to back up your entire house or a few circuits, a home standby generator will offer the best solution. If you just want to be able to power a few appliances and electronic, a large portable generator will meet your needs.

Leisure & Recreation: An inverter generator is ideal for activities like tailgating and camping. As a general rule of thumb, inverter generators are relatively quiet and have low Total Harmonic Distortion (THD) so they are safe for all electronics. Most inverter generators only offer up to 3000W of power, so if you need more, consider purchasing two and a parallel kit; or look for generators with low THD or Automate Voltage Regulation to ensure that you will not damage your sensitive electronics.

Jobsite: Portable generators are best for the jobsite because they offer mobility and can supply enough power for a variety of tools. Look for generators with enough running and starting watts to cover all your needs, as well as professional features like durable roll-cage frames, flat-free wheels, or auto-idle technology.

When choosing your generator, it’s also important to consider the outlets or ports on the control panel and the included cables. The outlets will let you know what types of things you can plug into your generator. There are a variety of outlet types. For example, if you would like to power your RV with your generator, you will want to make sure if comes with a 120-Volt RV Outlet. If you would like to be able to plug in a phone charging cable directly into your inverter, it should come with a USB port.

Generator Safety

Always read the owner’s manual and instructions for your generator and carefully follow all instructions and warnings in order to safely start and operate the generator. These tips are merely supplemental and are not intended to substitute reading of the owner’s manual.

Never run a generator indoors or in partly enclosed areas such as garages. Only use outdoors and away from windows, doors, vents, crawl spaces and in an area where adequate ventilation is available. Using a fan or opening doors and windows will not provide sufficient ventilation.

Operate the generator only on level surfaces and where it will not be exposed to excessive moisture, dirt, dust or corrosive vapors

Do not overfill the fuel tank. Always allow room for fuel expansion.

Never add fuel while unit is running or hot. Allow generator and engine to cool entirely before adding fuel.

Never store a generator with fuel in the tank where gasoline vapors might reach an open flame, spark or pilot light.

Do not connect your generator directly to your home's wiring or into a regular household outlet. Connecting a portable electric generator directly to your household wiring can be deadly to you and others. A generator that is directly connected to your home's wiring can 'back feed' onto the power lines connected to your home and injure neighbors or utility workers.

The generator must be properly grounded. If the generator is not grounded, you run the risk of electrocution. We strongly recommend that you check and adhere to all applicable federal, state and local regulations relating to grounding.

Allow at least five feet of clearance on all sides of the generator when operating.

Inspect the generator regularly and contact the nearest authorized dealer for parts needing repair or replacement.

Do not overload the generator. Do not operate more appliances and equipment than the output rating of the generator. A portable electric generator should be used only when necessary, and only to power essential equipment.

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Need to Know How Much Wattage?

Power requirement worksheet
Download our worksheet (PDF) to help determine your power requirements.