How to Size Your Generator: Don't Get Left in the Dark (or Overpay)
Picking the wrong generator size is one of the most common mistakes homeowners and business owners make. Too small, and your generator can't handle the load. Too large, and you're paying for power you'll never use. Here's a simple way to figure out exactly what size you need.
How Do You Calculate What Size Generator You Need?
Start by making a list of everything you want to power during an outage. For each appliance, find the wattage — usually listed on a label on the unit or in the owner's manual. Add up all those numbers, then add 20% as a safety buffer. That total gives you a solid starting point for the generator size you need.
Some appliances need more power to start than they do to run. Air conditioners, refrigerators, and well pumps are good examples. These are called surge loads or starting watts. Your generator must handle the surge, not just the running load. Make sure you account for that when adding up your numbers. Our team can walk you through it — call (775) 453-1048 and we'll help.
What's the Difference Between Running Watts and Starting Watts?
Running watts are the power needed to keep an appliance running steadily. Starting watts are the extra burst of power needed to start a motor-driven appliance like a refrigerator or air conditioner.
For example, a central air conditioner might use 3,500 running watts but need 5,000 starting watts when it kicks on. If your generator is only rated for 4,000 watts total, it can't handle that startup surge. This is why buying based on running watts alone can leave you in the dark.
When you browse generators for sale at Amerigen Power Solutions in Reno , you'll see both running and starting watt ratings listed. We help customers match their load requirements to the right unit so nothing gets left off the list.
Should You Size Up for Future Needs?
Yes — but don't go overboard. A generator that's too large runs inefficiently and may wear down faster because it's never operating at the right load. Sizing up by 10–20% above your calculated needs is smart. Going double the size you actually need is wasteful.
Think about any appliances or systems you might add in the next few years. Planning a hot tub? Adding an EV charger? Those require significant power and should be factored in now. That way, you won't outgrow your generator in a year or two. Our generator service team in Reno is happy to help you think through your long-term power needs. Call (775) 453-1048 for guidance.
Common Generator Systems in the Reno Area
In Reno and the surrounding Northern Nevada communities, standby generators ranging from 11kW to 22kW are the most common choice for residential use. These sizes cover the essentials for a typical Nevada home — HVAC, refrigerator, water heater, lights, and everyday appliances.
Larger homes with well pumps, electric heat, or multiple HVAC zones may need 22kW to 36kW units. Commercial properties and contractors typically work in the 30kW to 100kW range, depending on their operation. Reno's mix of older neighborhoods and new construction means generator needs vary a lot from property to property.
Let us help you match the right unit to your actual setup. Amerigen Power Solutions is located at 2995 Mill St in Reno. Call (775) 453-1048 or email wyatt@amerigenpower.com to get started today.
