Generator sizing, honestly: smaller usually wins.
Generators are the most fear-sold product in storm prep. The industry's incentive is to size you up; your outage's reality is that runtime, fuel, and noise matter more than peak watts. Here's the whole decision in plain English.
The goal isn't to power your house. It's to outlast an outage comfortably. Those are different projects with different price tags.
Start with the must-run list, not the aisle
Everything in sizing flows from one honest list: what genuinely has to run for days. For most households it's shorter than expected: the fridge, phones, some light, a fan, maybe a CPAP or a sump pump. Our sizing helper adds up your actual list; this guide explains what the answer means.
Two wattage facts drive the math. First, the nameplate on the appliance (usually stamped on the back or bottom) lists its maximum draw; that's the planning number, per the Department of Energy's guidance on estimating appliance energy use. Second, anything with a compressor or pump motor briefly pulls far more at startup than it does running, so sizing allows headroom for the largest motor, not for everything starting at once.
The four classes, and who each is really for
Battery power stations
Not generators at all: big batteries with outlets. Indoor-safe, silent, zero maintenance, and they cover the phones-lights-CPAP-router tier for a night or two, longer with solar input. If your must-run list has no compressor in it, start here before pricing engines.
Small inverter generators
Quiet, light, and frugal with fuel. Runs the essentials tier, and pairs well with a battery station (engine by day, battery by night). The class most people should at least consider before buying bigger.
Mid-size inverter and portable units
The fridge-plus-essentials sweet spot, and the honest answer for most storm-country households that want an engine. Inverter models in this class cost more than open-frame ones and are dramatically quieter, which matters more than people expect on night five.
Large portables and standby installs
Large portables run pumps, window ACs, and kitchens, at the price of noise, weight, and serious fuel appetite. Permanently installed standby units (with a transfer switch, permit, and usually natural gas or propane) are the right call for central AC, electric water heat, well-dependent homes, or medical equipment that can't tolerate gaps. That's an installer conversation, not a checkout page.
The fuel math nobody does at the store
A generator without stored fuel is a lawn ornament. Bigger engines burn more per hour at the same task, which means the oversized unit doesn't just cost more once; it costs more every hour of every outage, and it drains your stored gasoline fastest exactly when stations are down. Gasoline also ages: it needs stabilizer and rotation. Propane stores indefinitely and many portables now run on both, which is why dual-fuel is one upsell that often is worth it.
- Outdoors only, always. Never in the house, never in the garage (open door included), well away from windows and doors. Carbon monoxide from generators kills people in the days around storms. A battery CO alarm near sleeping areas is part of the purchase.
- Never plug a generator into a wall outlet. Backfeeding can electrocute the line workers restoring your street and the neighbors on your transformer. Heavy-duty outdoor-rated cords to appliances, or a licensed electrician installs a transfer switch or interlock. There is no third option.
Buy it in the calm, run it in the calm
A generator bought the day before a storm is the most expensive way to buy the wrong generator: selection is gone, prices are peaking, and there's no time to learn the machine. The off-season sequence: honest list, size it, buy the class the list says, then a full test run (fuel, oil, an actual extension cord to an actual fridge) before June. Twenty minutes of practice in the sunshine is worth an hour of manual-reading in a stairwell by flashlight.
Educational only, not electrical, safety, or purchasing advice; wiring and standby decisions belong with a licensed electrician. Class boundaries describe how machines are commonly sold, not a standard; wattage guidance follows the nameplate method (V22, V23), and the safety rules are V4 and V27 in our verification log, data-verified at build 2026-07-08.