Selecting the right size generator is crucial for ensuring you have adequate power during an outage without overspending on unnecessary capacity. Whether you are considering a backup generator installation in North Carolina for your home or need a commercial generator installation, understanding how to accurately determine the right generator size is essential. This guide will help you navigate through the process, ensuring you make an informed decision based on your specific power requirements.

Understanding Generator Size

Generators are rated by watts (W) and kilowatts (kW), which measure the power they can deliver. Residential generators typically range from 5,000 to 20,000 watts, while commercial generators can go up to 2 MW (2,000 kW) or more, depending on the facility’s needs. The right size depends on the total wattage of all the appliances, tools, or systems you need to run simultaneously.

Step 1: Determine Your Power Needs

The first step in choosing the right generator size is to list all the electrical devices you plan to operate during a power outage and note their wattage requirements. Most appliances have a label that lists their power requirements in watts. Add up the wattage of all these items to determine your total power needs.

Critical Load Assessment

Identify which appliances are essential during a power outage. For homes, this might include the refrigerator, heating system, lights, and a sump pump. For businesses, essential items could include servers, safety lighting, and equipment necessary for continued operation.

Starting vs. Running Watts

Some appliances, particularly those with motors, require more power to start than to run. This startup power is known as “starting watts” or “surge watts,” while the power needed to run the appliance is termed “running watts.” Ensure your generator can handle the total running watts and the highest starting watts of any appliance you plan to use.

Step 2: Decide on the Type of Generator

Portable vs. Standby Generators

  • Portable Generators: These are generally smaller and can be moved around. They’re suitable for powering a few appliances and are more budget-friendly.
  • Standby Generators: Installed permanently and offer automatic power restoration when the power goes out. They are more suitable for homes or businesses that need a seamless transition to generator power during outages.

Fuel Type

Generators can run on various fuels including gasoline, diesel, propane, or natural gas. Each fuel type has its advantages and limitations. For instance, natural gas generators require a gas line, but provide an almost unlimited fuel supply, while diesel generators are more fuel-efficient but need regular refueling.

Step 3: Consider Installation and Operational Factors

Backup Generator Installation in North Carolina

For homeowners and businesses in North Carolina considering a backup generator, professional installation is crucial. This ensures that the generator is correctly integrated into your existing electrical system and complies with local codes and regulations.

Commercial Generator Installation in North Carolina

Businesses require careful consideration of additional factors such as noise ordinances, fuel storage limitations, and the potential need for larger capacity units or multiple generators. It’s advisable to work with a company experienced in commercial installations to ensure that all aspects of the setup are professionally handled.

Step 4: Evaluate Additional Features

Automatic Transfer Switch

An Automatic Transfer Switch (ATS) is essential for standby generators, as it automatically switches the power source from the utility to the generator when an outage is detected.

Generator Enclosures

Consider weatherproof and soundproof enclosures, especially for outdoor installations. This not only protects the generator from the elements but also reduces noise pollution.

Maintenance and Warranties

Regular maintenance is crucial to ensure the longevity and reliability of your generator. Opt for models with accessible parts and good warranty terms. Additionally, some suppliers offer service contracts that cover regular maintenance.


Choosing the right size generator involves understanding your power needs, selecting the appropriate type of generator, considering installation requirements, and evaluating additional features that enhance functionality and convenience. Whether it’s for residential backup or commercial purposes in North Carolina, taking the time to assess your needs comprehensively will ensure that you invest in a generator that reliably meets your demands during power outages. Remember, consulting with professionals for backup or commercial generator installation in North Carolina can provide additional insights and help tailor solutions to your specific requirements.