How do I choose a whole-home generator size?

List the circuits that must run together, then have an installer calculate their running and motor starting loads.

Why do air conditioners affect generator size?

Air conditioners contain motors that can need extra power at startup, so the installer must account for their starting load.

Must a generator power every circuit in the home?

No. A system can cover selected essential circuits or broader home loads, depending on its design and load management.

What information should I provide for a sizing assessment?

Share the service-panel details, essential circuits, cooling equipment, pumps, major appliances, fuel type, and expected simultaneous use.

Surfside Beach Local service guide

Repairs and home systems

Whole-home generator sizing in Surfside Beach, SC

Generator sizing starts with the electrical loads that must run together during an outage.

Source: Generac wattage guide (opens in a new tab)

Choose the loads that matter

Start with the circuits that must work during an outage. Common priorities include refrigeration, lighting, internet equipment, pumps, and selected cooling equipment.

For context, the Energy Information Administration reports that a U.S. residential customer purchased a yearly average of 10,791 kilowatt-hours in 2022. Source: EIA home electricity use FAQ (opens in a new tab)

Decide which loads must run at the same time. A selected-load plan may need less capacity than a plan for broader home coverage.

Account for starting loads

Motor-driven equipment can draw extra power for a short time at startup. Air conditioners, refrigerators, and pumps can affect the required capacity.

Generac distinguishes continuous running watts from the extra watts needed to start motor-driven equipment. Source: Generac wattage guide (opens in a new tab)

Ask the installer to calculate running loads and starting loads from equipment data rather than appliance-count estimates.

Review load management and fuel

Load management can keep selected high-demand equipment from starting at the same time.

Fuel type, available fuel capacity, and delivery limits also shape the system design. Ask the installer to assess the electrical and fuel systems together.

Prepare for the sizing visit

List the essential circuits and major equipment. Include cooling systems, pumps, electric water heating, cooking equipment, and medical equipment.

Share photos of equipment labels and the service panel when the installer requests them.

Request a generator sizing assessment

Share the property address, service-panel details, essential loads, fuel type, and expected simultaneous use.

Guides for whole-home generators

Standby versus portable generators in Surfside Beach, SC

Compare standby and portable generators for hurricane-season outages, including setup, fuel, loads, and carbon monoxide safety.

Town rules

Contractor licensing rules

Check when covered residential specialty work over $500 requires state registration.

Hurricane and evacuation rules

Prepare to follow evacuation orders that state and local authorities announce by zone.

Questions about whole-home generators

How do I choose a whole-home generator size?: List the circuits that must run together, then have an installer calculate their running and motor starting loads.
Why do air conditioners affect generator size?: Air conditioners contain motors that can need extra power at startup, so the installer must account for their starting load.; Source: Generac wattage guide (opens in a new tab)
Must a generator power every circuit in the home?: No. A system can cover selected essential circuits or broader home loads, depending on its design and load management.
What information should I provide for a sizing assessment?: Share the service-panel details, essential circuits, cooling equipment, pumps, major appliances, fuel type, and expected simultaneous use.