Install a Generator Cost in O Fallon, MO in 2026
Most Install a Generator projects in O Fallon, MO cost between $1,600 and $27,000. The typical price is $8,000.
Standby generators are dominated by equipment cost and the gas line run.
O Fallon prices track the national average closely. Costs here are close enough to the national picture that the adjustment barely moves the number.
What drives the price
- Panel capacity and whether an upgrade is needed
- Running new circuits through finished walls
- Permit and inspection in your jurisdiction
- Aluminium wiring or knob-and-tube remediation
Usually included
- Licensed electrician labour
- Wire, boxes, breakers and devices
Usually extra
- Drywall repair after the walls are opened
- Fixtures you supply
- Utility service upgrades