Don’t shop by the biggest number on the box.
Generator sizing starts with your actual loads. Running wattage is the continuous demand; motors and compressors can require a higher starting surge. Build your list around the appliances and circuits you truly need.
Running Watts
Add the continuous wattage of the equipment you expect to operate at the same time. This is the baseline load your generator must sustain.
Starting Watts
Refrigerators, freezers, pumps and other motor-driven equipment can draw more power for a short period when starting. Leave room for those surges instead of sizing exactly to the running total.
Essentials vs. Whole House
A refrigerator, lights, internet and a few outlets are a very different job from central air, electric water heating and other large loads. Decide what must run before deciding how much generator to buy.
Transfer Switch
If you want to power home circuits or hardwired equipment, talk with a qualified electrician about a properly installed transfer switch or approved interlock arrangement. Never backfeed through a household outlet.
Build your outage list first.
Write down the equipment you consider essential, find each item’s rated running load and account for the largest relevant startup surge. That gives you a much more useful target than buying solely by generator class or advertised peak wattage.
Basic essentials
Think refrigerator/freezer, selected lights, modem/router, phone charging and a few outlets. A smaller generator may be sufficient if you deliberately manage which loads run together.
More home systems
Well pumps, window A/C units and other motor loads can push requirements higher because of startup demand. Verify equipment labels and manuals instead of relying on generic wattage charts alone.
Fuel & runtime matter
More output usually means more fuel consumption, weight and noise. The best size is enough capacity for your plan with sensible reserve—not automatically the largest unit you can afford.
Look for CO safety technology
Automatic carbon-monoxide shutoff technology is worth prioritizing, but it does not make indoor or near-home operation safe. Proper outdoor placement is still mandatory.
Size the plan, then size the generator.
Add the loads you intend to run together, account for startup demand, and leave reasonable headroom. If the goal is powering home circuits rather than individual extension-cord loads, have the connection method designed or installed by a qualified electrician.