Standby Generator Cost Calculator
| Path | Installed | Run cost | Covers |
|---|---|---|---|
| Standby 14-20 kW | $12,000-17,000 | $25-45/day (gas) | whole house, self-starts |
| Portable + switch | $1,500-3,500 | $10-20/day | essentials, manual start |
| Portable inverter | $700-1,500 | $8-15/day | fridge + devices, no well |
The standby generator quote that shocks people is almost never about the machine — a 14-20 kW air-cooled unit lists for $4,000-6,000. The $12,000-17,000 installed number is the concrete pad, the licensed electrician wiring an automatic transfer switch, the plumber or gas fitter running the fuel line, the permit, and sometimes a utility inspection. Understanding which line is which is the difference between buying outage insurance and financing a patio toy you start twice a year.
The other honest lever is the load list. Keep the furnace fan, the refrigerator, the well pump, the internet box and some lights on and your essential load is 6-8 kW — a comfortable mid-size standby. Add central air, an electric range and an electric dryer and you are shopping at 20+ kW, where installed prices climb another $3,000-6,000 and the fuel bill during an outage doubles. This calculator prices both paths — the automatic standby and the portable-plus-manual-switch route — plus what each day of running actually burns, because the cheapest generator is the one sized for the outage you will actually have.
How to use
- Build the essentials list, not the wishlist: walk the house during a calm evening and count what actually matters when the street is dark — heat, water, food, phones, a lamp or two.
- Pick the fuel you already have: natural gas never runs out but depends on the grid pressure staying up; propane stores in a tank you own; diesel stores in cans you fill and rotate.
- Compare the totals honestly: the standby starts itself in ten seconds whether you are home or not; the portable path costs a tenth as much but needs you outside in the storm pulling a rope and refilling cans.
Frequently asked questions
How much does a whole-house standby generator cost installed?
Budget $12,000-17,000 all-in for the common 14-20 kW air-cooled class: roughly $4,000-6,000 for the unit and $6,000-10,000 for the pad, automatic transfer switch, fuel run, permits and labor — more with long gas-line runs, liquid-cooled engines or difficult pads. Quotes vary widely by market, so collect three and make each line item visible.
Can I just use a portable generator instead?
For essentials, yes: a $700-1,500 portable inverter unit plus a manual transfer switch ($300-800 installed) covers a furnace, fridge, well pump and lights for a tenth of the standby price. The tradeoffs are manual starts in bad weather, refueling every 6-10 hours, noise, and no coverage when nobody is home — the transfer switch is not optional: backfeeding a house panel without one can kill a lineman.
What does it cost to run per day?
A mid-size natural-gas standby at half load burns roughly $25-45 of gas per day depending on local rates; propane models burn about a 20-pound cylinder's worth of energy every 4-6 hours at similar load, so outage-length fuel storage becomes the real planning question. Portable gasoline units at essentials load burn 2-4 gallons a day — cheap to run, awkward to fetch during exactly the weather that caused the outage.
Do standby generators need maintenance?
Yes — an annual service (oil, filters, valve check, battery test) runs $200-400 and most manufacturers condition warranty coverage on it. The weekly self-test consumes negligible fuel and is the feature that makes the standby worth its price: the machine that starts itself in ten seconds has usually been proving so quietly every Tuesday for years.
Does a generator increase home value?
Slightly, and unevenly: in storm-prone markets with frequent outages a transferable-warranty standby is a genuine selling point appraisers recognize, while in reliable-grid neighborhoods it is mostly a personal convenience. Nobody buys a house for the generator, but between two equal houses, the one that stayed warm during the last ice storm has a story.