How to Choose a Generator for Power Outages

Buying a generator for power outages means making five decisions in the right order: what you need to power, how many watts that takes, which type of generator fits, which fuel suits your storage and supply, and how it connects to your home. Skip a step and you end up with a machine that is too small, too loud, too thirsty, or unable to power the furnace you bought it for. This guide walks through each decision with a worksheet approach you can apply to any home.

Decision 1: Choose your coverage level

Most households find the “essentials plus comfort” tier covers what really matters, at a fraction of the cost of whole-home coverage.

Decision 2: Calculate watts with a simple worksheet

• List every device you want to run at once, with its running watts from the label or manual.
• Add the running watts together.
• Find the device with the largest starting surge and add the difference between its starting and running watts.
• Add 20 percent headroom.

That home needs a generator rated around 5,000W running.

Decision 3: Pick the generator type

Inverter generator

Clean power safe for electronics, quiet operation often at 50 to 60 dBA, and excellent fuel economy at light loads. Best for essentials and comfort tiers up to about 5,000 to 7,000W.

Open-frame portable generator

More watts per dollar, handles big surges, louder at 65 to 75 dBA. Good for larger homes with well pumps or multiple motor loads on a budget.

Home standby generator

Permanently installed, runs on natural gas or propane, starts automatically. Best for whole-home coverage, frequent outages, or households that cannot manage portable equipment.

Decision 4: Choose the fuel

For most portable buyers, dual fuel is the best balance of availability and storage life.

Decision 5: Plan the connection

Extension cords are fine for a fridge and a few plug-in devices. Hardwired items such as furnaces, well pumps, and sump pumps on dedicated circuits need an inlet box with an interlock or a transfer switch installed by a licensed electrician. Choose the generator’s twist-lock outlet to match: L14-30 for most units up to about 7,500W, 14-50 for larger ones. Never backfeed through a dryer outlet.

Other factors worth checking

• Noise rules: HOAs and neighborhoods may restrict loud equipment, especially at night.
• Runtime at 25 and 50 percent load: aim for at least 8 hours per tank.
• Automatic CO shutoff and low-oil shutdown.
• Electric start and a battery maintainer.
• Wheel kit and handles; generators over 100 lb need them.
• Parallel capability for inverters, allowing a second unit later.

Budget snapshot

FAQ

What size generator do I need to run my house during an outage?

For essentials plus comfort, most homes need 3,500 to 5,000W. Add well pumps or several motor loads and plan for 7,500W. Whole-home coverage requires a standby generator.

Do I need a transfer switch?

If you want to power hardwired circuits like a furnace or well pump, yes: an inlet with an interlock or a transfer switch installed by an electrician. For plug-in appliances only, heavy-duty extension cords are sufficient.

Bottom line

Choose your coverage level, calculate running watts plus the largest surge with 20 percent headroom, then match the type and fuel to your home and outage history. For most households, a 3,500 to 5,000W dual fuel inverter generator connected through an inlet box delivers reliable, safe outage power without the cost of a whole-home system.