Generator Cost: What You'll Pay by Type in 2026

A generator costs anywhere from $400 for a small recreational inverter to $20,000 for a fully installed whole-home standby. The gap is that wide because “generator” covers two very different products: a portable machine you roll out during an outage, and a permanent standby that switches on by itself. Most homeowners buying backup power for the first time spend around $1,000 to $1,500 on a portable, or $7,000 to $12,000 installed if they go standby.

Deciding between the two, and sizing whichever you pick, is the whole cost question. Here’s how to think it through.

Portable vs standby: the real split

A portable generator runs $400 to $2,500 depending on output. You store it, wheel it out when the power goes, fill it with gas, and either run cords to appliances or feed the house through a transfer switch. It’s the affordable answer for occasional outages, and a mid-size unit ($700 to $1,500) will keep the fridge, furnace, and some lights going.

A standby generator is a permanent installation, $7,000 to $20,000 all-in. It sits on a pad outside like an AC condenser, runs on your natural gas or a propane tank, and an automatic transfer switch starts it within seconds of an outage with nobody home. The unit itself is only $2,000 to $6,000; the rest is the pad, the transfer switch, the gas line, permits, and a licensed electrician’s labor, which typically runs $3,000 to $7,000. If you lose power often or can’t be home to run a portable, that’s what the money buys.

What size generator do I need?

Sizing is where people overspend or come up short. Add up the running watts of what you must power, then add starting-watt headroom for motors (a fridge or furnace blower spikes two to three times its running draw for a second on startup).

• Essentials only (fridge, furnace fan, lights, phone charging): roughly 3,000 to 5,000 running watts. A mid portable covers it.
• Most of a house (add a well pump, microwave, some outlets): 6,000 to 9,000 watts. A large portable or a small standby.
• Whole home with central AC and electric range: 12,000 to 20,000 watts. Standby territory.

Don’t size to the sum of everything you own; size to what actually runs at once during an outage. A right-sized 7,500-watt unit beats an oversized 15,000-watt one you paid double for and never load past a third.

What it costs to run per hour

Fuel is the number rarely printed on the box. A mid portable burns roughly 0.5 to 0.75 gallons of gasoline per hour at half load, so a day of outage can run $20 to $40 in fuel alone, and gas is hard to find when the power’s out region-wide. Standby units on natural gas cost less per hour and never need refueling, which is a real part of their value on a long outage. Both need oil changes on a schedule, and standby units get an annual service, typically $150 to $300.

Which generator do I actually need?

• Rare, short outages; want to spend the least: a mid portable and a few heavy cords.
• Regular outages; want the house mostly normal: a large portable plus a manual transfer switch.
• Frequent or long outages, or you travel: an installed standby sized to your real load.

The clean, affordable buy for most people is a large portable with a transfer switch. Step up to standby when the outages are frequent enough, or long enough, that starting a portable by hand in the dark stops being acceptable.