One of the most common mistakes homeowners make when purchasing a standby generator is choosing the wrong size. Go too small and your generator will struggle under load or shut down unexpectedly. Go too large and you’ll spend more than necessary upfront and on fuel. Getting the sizing right is one of the most important steps in the buying process.
Why Size Matters
Generator capacity is measured in kilowatts (kW). Your home’s electrical loads—everything that draws power—need to be within that capacity for the generator to operate safely and efficiently. When a generator is overloaded, it either shuts down automatically (if it’s a good unit) or it runs under stress, which accelerates wear and can cause damage.
Essential vs. Whole-Home Coverage
The first question to answer is: what do you want to power during an outage?
Essential circuits only: If you want to keep the essentials running—refrigerator, lights, sump pump, heating system, and a few outlets—a generator in the 10–16 kW range is typically sufficient for most homes.
Whole-home coverage: If you want to run everything as if nothing happened—central air conditioning, electric appliances, EV charger, hot tub—you’ll need a larger unit, potentially 20 kW or more depending on your home’s total load.
Key Loads to Account For
Air conditioning compressors, well pumps, and electric water heaters have high startup (surge) demands in addition to their running watts. These surge loads need to be factored into the sizing calculation—not just the steady-state draw.
A Pow’r Point technician performs a professional load calculation during the consultation process, accounting for all of these factors so you get the right generator the first time.
Don’t Guess—Get a Professional Assessment
Online calculators can give you a rough idea, but they can’t replace a professional evaluation of your specific home, electrical panel, and priorities. Our team has helped hundreds of families across Maine and New England choose the right generator size—and get the most value from their investment.
Contact Pow’r Point today for a free consultation and let us help you find the generator that’s exactly right for your home.
