What Size Generator do I need for my home?

A Simple guide to choosing the right backup power for your home - from wattage basics to professional sizing.

Start with the basics:
what is wattage?

Every appliance in your home uses electricity. The amount it uses is measured in watts. Some devices use very little — like an LED bulb. Others use a lot — like your central air conditioner.

To pick the right generator, you need to know the total watts of everything you want to keep running during an outage.

Two numbers you need to know

Most appliances need two different wattage numbers — one to start up, and one to keep running.

1. Starting watts - The extra power needed to kick on. This is always higher — sometimes 2–3× more than running watts.
2, Running watts - The steady power used once the appliance is on. This is the lower, ongoing number.
Why it matters

If your generator can't handle the startup surge, it will trip or fail — even if the running load seems fine.

Common appliance wattages

Here's a quick reference for typical home appliances:
Chart explains starting watts and running watts of various home appliances

how to calculate what you need

  1. List your essential appliances. Write down everything you would need during a power outage - A/C, fridge, lights, medical devices, etc.
  2. Find both wattage numbers. Check the label or manual for starting and rubbing watts for each appliance.
  3. Add up the running watts. Total all the running watts for everything you'll use at the same time.
  4. Add the highest starting watts. Find the appliance with the largest startup surge and add that to your running total.

Pro Tip

Your generator needs to handle the highest combination of startup and running loads — not just the running total alone.

Homeowner pours coffee cup in kitchen while the home is being powered by a Cummins generator during an outage.

Which generator size is right
for your home?

Smart Load Management

Even with the right size generator, you can get more out of it with smart load management. Our managed whole house approach lets you:

  • Keep critical systems like A/C and refrigeration running at all times
  • Temporarily pause high-draw appliances like ovens or dryers during peak load
  • Avoid overloading your system during surges
  • Maximize comfort without sacrificing safety

Most homes in the Memphis area fall into one of these categories:

Memphis Area Example

A typical 2,000 sq ft home with gas heat and a single 4-ton A/C unit is well covered by a 20 kW Cummins air-cooled generator. It handles heating, cooling, all lights, and standard outlets throughout your home.

Distinguishes different sizes of generators and capabilities

Why Professional Sizing Matters

Generator sizing isn't just math — it involves your home's specific wiring, load patterns, and priorities. Getting it wrong means either an underpowered system or overspending on capacity you don't need.

At Benchmark Electric, our process includes:

  • An on-site consultation with a dedicated sales consultant
  • A full review of your critical systems and lifestyle needs
  • A recommendation tailored to your budget and priorities
  • Expert installation and ongoing support

Ready for Reliable
Backup Power

Contact Benchmark Electric for your free home assessment. We'll help you find the right generator - no guesswork.

Request An Onsite Consultation & Quote