Whole House Generator Cost Calculator
Estimate the installed cost of a whole-house standby generator from its size in kW, an installed rate per kW, and base costs for pad, permits, and transfer switch.
How this calculator works
A whole-house generator installation has two kinds of cost: things that stay roughly the same regardless of generator size, and things that scale with it. This calculator separates the two so you can see how each part of the estimate is built.
The base cost covers the transfer switch, concrete pad, and permit. On top of that, the generator size in kW is multiplied by an installed rate per kW to capture the cost of the unit itself and the labor to install it.
Formula: Total cost = base cost (permits, pad, transfer switch) + generator size in kW × installed rate per kW.
Worked example
A 20 kW generator, $700/kW installed rate, $2,000 base cost:
- Generator and labor: 20 × 700 = $14,000
- Total: 2,000 + 14,000 = $16,000
Notes
The automatic transfer switch, concrete pad, and electrical permit are largely fixed costs regardless of generator size, while the generator unit and its installation labor scale with size. A natural gas hookup, if not already present at the site, is a separate cost not included in this estimate.
How to use
Enter the generator size in kW, your installed rate per kW, and a base cost for the pad, permit, and transfer switch. The calculator adds the scaling generator cost to the fixed base cost to give you a total installed estimate. Use it to compare generator sizes before getting a formal quote.
Electrical work is code-governed and safety-critical. Confirm circuit, conductor, and equipment sizing with a licensed electrician and your local code.
Frequently asked questions
What's included in the base cost for a whole-house generator?
The base cost typically covers the automatic transfer switch, the concrete pad the generator sits on, and the electrical permit. These costs stay largely fixed no matter how big a generator you install, because they're tied to the installation itself rather than the generator's output capacity.
Why does cost scale with generator size in kW?
The generator unit itself, and the labor to install it, both get more expensive as the output size in kW goes up. A larger unit costs more to buy and typically takes more work to wire in, so the calculator applies your installed rate per kW on top of the fixed base cost to capture that scaling.
Is a natural gas line included in this estimate?
No. If your home doesn't already have a natural gas hookup near the installation site, running one is a separate cost on top of the generator, pad, transfer switch, and permit figures this calculator produces. Ask your installer for a separate quote on gas line work if you don't already have service there.
How accurate is this estimate for a real quote?
It's a planning estimate built from your own inputs for generator size, installed rate per kW, and base cost, so its accuracy depends on how close those inputs are to real local pricing. Installed rates vary by region and installer, so use this to compare scenarios and then confirm the real number with a licensed electrician's quote.
Estimates only. Verify quantities with your supplier before purchasing.