Generator Installation Cost: Standby Prices by Size
Installing a whole house standby generator costs most homeowners $1,513 to $8,805, with an average near $5,158. The unit drives the price, but the transfer switch, concrete pad, gas line and permits add thousands more.
What generator installation costs
HomeAdvisor puts whole house generator installation at $1,513 to $8,805, with most homeowners paying around $5,158 all in. The floor sits near $350 for a modest portable setup and the ceiling around $13,500 for a large standby system.
That spread is wide because the figure covers two different purchases. One is a portable unit you roll out and start by hand. The other is a permanently wired standby generator that senses the outage and starts itself. If you want the second kind, ignore the bottom of the range entirely.
A useful cross check comes from the manufacturer side. Cummins lists its own units from about $4,500 for a 13 kW model to $6,000 for a 20 kW model, and puts installation labor separately at $2,000 to $4,000. Add the automatic transfer switch at $600 to $1,200 and a realistic standby project lands somewhere between $7,000 and $11,000. The survey average is lower because it blends in the cheaper portable jobs.
Cost by generator size
| Capacity | Suits | Unit cost |
|---|---|---|
| 1 – 6 kW | Portable backup | $500 – $1,800 |
| 7.5 – 10 kW | Homes under 1,500 sq ft | $2,000 – $3,500 |
| 14 – 18 kW | Critical systems, 1,500 – 3,000 sq ft | $4,000 – $5,500 |
| 20 – 24 kW | Large homes, 3,000 – 5,000 sq ft | $5,000 – $6,500 |
| 26 – 32 kW | Large homes plus extra appliances | $6,500 – $15,000 |
Sizing is where money gets wasted. Buying more capacity than your home draws only raises the bill, and anything above 30 kW needs liquid cooling, which adds thousands to the unit price on its own. A load assessment from the installer is worth insisting on before you pick a model.
Fuel type and the parts nobody quotes first
| Item | Cost |
|---|---|
| Natural gas unit | $2,000 – $21,000 |
| Liquid propane unit | $2,000 – $21,000 |
| Diesel unit | $3,000 – $20,000 |
| Gasoline unit | $500 – $3,000 |
| Labor | $1,500 – $5,000 |
| Automatic transfer switch | $2,000 – $30,000 |
| Manual transfer switch | $500 – $2,000 |
| Concrete pad | about $1,000 |
| Permits | $50 – $200 each |
| Propane tank, 250 to 500 gallon | $500 – $2,500 |
The transfer switch is required by the National Electric Code, not optional, because it stops your generator backfeeding into the utility line and endangering line workers. Most homes need two permits, one for the electrical work and one for the fuel line or tank.
Natural gas is the usual choice for standby units since it feeds from the existing house supply with no tank to refill. Propane suits rural properties without a gas line but needs storage. Gasoline is cheapest up front and almost always portable.
One cost that often surprises people is the panel. Some installations need a subpanel at $500 to $2,000, and a large generator can require replacing the main panel outright, which is its own project. If your service is already near capacity, read up on electrical panel upgrade costs before budgeting.
What it costs to keep
Servicing runs $171 to $395 per visit, averaging $273, with yearly upkeep between $85 and $706 depending on how often the unit actually runs. A standby generator averages about $600 a year to maintain against roughly $50 for a portable one. Batteries need replacing roughly every three years.
Two tune ups a year, before summer and before winter, is the common recommendation, and the point is to find faults while the grid is still up rather than during the storm.
Is your quote reasonable?
For a standby system, a total between $7,000 and $11,000 covering unit, transfer switch, pad, gas connection and permits is a normal mid range quote. A rule installers use is that installation roughly matches equipment cost, so a $6,000 generator and switch pointing at a $12,000 project is not automatically padded.
Check that the quote itemises the transfer switch, the pad, the gas line connection, the permits and any panel work, because those are the items that turn a tidy headline number into a surprise. Collect at least three written quotes and confirm the installer is licensed, since the job involves both gas fitting and electrical work. Ask whether the price includes the load assessment, and be wary of a quote that names a generator model before anyone has measured what your home actually draws.