Backup generators cost from $500 for a small portable unit to $25,000 or more for an installed whole-house standby system.
The right answer for your home depends on what you want to keep running when the power goes out. A small portable gas generator that handles your fridge, lights, and phones runs about $500 to $1,500. If you need to power a well pump, heavier appliances, or more of your home with a larger portable or inverter unit, you’re looking at $1,500 to $4,000 or more. Whole-house standby systems, which are permanently installed and tied into a transfer switch, span a much wider range: roughly $4,000 to over $25,000, with many natural-gas setups landing around $10,000 to $13,000 installed.
The biggest mistake shoppers make is comparing only the sticker price. Installation, transfer switches, concrete pads, permitting, and site work can add thousands to a standby unit.
What Drives the Price of a Backup Generator?
Three factors set the cost: fuel type, power output, and how the generator connects to your home.
Fuel type. Gas, propane, natural gas, diesel, and dual-fuel models all appear in current market guidance. Portable gas units are the cheapest upfront. Dual-fuel and inverter models cost more because they run quieter and use fuel more efficiently.
Power output. Retailers list two numbers: running watts and surge watts. Surge watts matter because appliances like refrigerators and well pumps draw extra power on startup. Buying only on the running-watt number leaves you short when the compressor kicks on.
Connection. A portable unit plugs into appliances directly. A standby unit feeds your whole house through a transfer switch, which needs professional electrical work. Lower-priced whole-house quotes often skip the transfer switch, pad, and labor — that’s where the hidden costs live.
If you’re comparing models and wondering what a fair price looks like, our tested backup generator price roundup breaks down what each category should cost.
Portable Versus Standby: Two Different Price Worlds
Portable units are the budget route to backup power, and standby systems are a home improvement project.
Here’s how the categories compare at current US retail levels:
| Generator Type | Typical Installed Price | What It Powers |
|---|---|---|
| Small portable gas | $500 – $1,500 | Fridge, lights, phones, a few circuits |
| Large portable / inverter | $1,500 – $4,000+ | Well pumps, heavier appliances, more of the home |
| Battery / solar backup | $1,200 – $5,000+ | Fridge, electronics; silent and no fumes |
| Whole-house standby (gas) | $4,000 – $25,000+ | Entire home automatically |
| Natural-gas standby | $10,000 – $13,000 typical | Entire home, no fuel refills |
Battery-based generators are a separate conversation. A 5,000-watt-class setup starts around $1,200 and can pass $5,000 once you add batteries and accessories. They cost more per watt than gas, but they run silently, need no fuel storage, and carry zero carbon-monoxide risk.
What Most Buyers Miss About Total Cost?
Fuel-burning portables come with a serious safety caveat: carbon monoxide. Run a gas generator in the garage or near a window and CO can build to deadly levels fast. That’s not a price line item, but it should shape which model you buy.
Other overlooked costs:
- Installation and transfer switch. A standby unit needs a licensed electrician, a concrete pad, and often a permit. These routinely add thousands.
- Fuel storage and runtime. A portable running all day needs multiple gas cans cycled through. Propane and natural gas sidestep that chore.
- Noise. Open-frame portables are loud. Inverter models cost more partly because they’re quieter.
- Startup loads. If the fridge and well pump start together, your surge watts need headroom.
Wirecutter’s portable generator testing has long noted that running watts and surge watts are the two numbers that matter most when sizing a unit for real appliances.
What Should You Spend?
Match the generator to the outage you’re actually preparing for.
- Weekend outages, basic needs: a $600 to $1,200 portable gas unit covering the fridge and lights is a sound buy. Budget extra for fuel and an extension-cord setup.
- Frequent, longer outages or a well pump: plan on $1,500 to $4,000 for an inverter or larger portable that keeps water flowing.
- Whole-home coverage, no refueling: expect $10,000 to $15,000 installed for a natural-gas standby, with the range stretching past $25,000 for large homes and difficult sites.
- Solar or battery backup: budget $1,500 to $5,000+ if you want clean, silent power for critical circuits.
Angi’s installation-cost data confirms that electrical work, transfer-switch hardware, and site conditions move the final number more than the unit itself. Get two or three quotes before committing to a standby install. Whatever you choose, verify your surge-watt needs first, and keep fuel-burning units far from any window, door, or garage.
References & Sources
- Wirecutter (The New York Times). “The Best Portable Generator.” Notes running vs. surge watts as the key sizing specs and highlights CO-sensor-equipped models.
- Angi. “How Much Does It Cost to Install a Generator?” Documents installed-cost drivers like transfer switches, electrical work, and site conditions.
