Residential, Cook Electric
Written by Larry Cook

Buy the Right Standby Generator Size for Your Home – Part 2

Part 2 will cover the topics Kilowatts & ATS, Running Watts & KVA, and Choosing Your Standby Generator.

Kilowatts & ATS

The size of a standby generator is determined by its output of kilowatts (kW). A kilowatt is 1,000 watts, and so a 20kW generator produces 20 kilowatts, or 20,000 watts of electrical power.

Every generator must be paired with an automatic transfer switch (ATS), which activates and deactivates the standby-power system. For example, a standby generator connected to a 200-amp breaker panel will require a 200-amp ATS.

Running Watts & KVA

The proper generator size will be determined by totaling the running watts and starting kVA of all the circuits, appliances, and electrical machines connected. A calculation for each must be made.

Basically, kVA equals 1,000 volt-amps, a volt being electrical pressure and amp being electrical current. Knowing the starting kVA is required because every time an electrical motor turns on, it creates an additional electrical surge the generator has to be capable of handling. Running watts is the power being consumed by an electrical machine while functioning normally.

After the identification of standby electrical circuits, the electrician will be able to sum up the total running watts and starting kVA to calculate the total electrical load for the whole system. Only then will an electrician be able to accurately determine the correct size of the standby generator.

Choosing Your Standby Generator

The first step is contacting a licensed electrician who is an expert in standby generators and ask for a site survey. This will include an inspection of your house’s electrical panel and circuits, along with a conversation about the appliances and electrical equipment you want powered.

As discussed before, a load calculation and then the right size of the generator will be determined. Afterwards, the type of generator (air-cooled or liquid cooled), how it will be powered (LP or natural gas), installation location, and other options will be selected. The electrician will then provide an estimate for review and discussion prior to moving forward on the project.

Electrical Peace of Mind

Providing professional electricians since 1988 in Maryland, Cook Electric is the company you can rely on for all your electrical service needs. For knowledgeable, fair, honest, reliable, and conscientious service, call Cook Electric today at (410) 266-9040. We will be very glad to help you.