Standby Generator Installation: What to Expect

What gets installed

Before the steps, here's what the crew is putting in:

• The generator, sized to your load.
• A pad. A concrete slab or compacted pea gravel, depending on the unit and local rules.
• A fuel line from your natural gas meter or a propane tank.
• A transfer switch next to your main breaker panel. Generac's lineup includes service-entrance-rated switches and essential-circuit switches.
• Control and power wiring between the generator and the switch.
• Sometimes: a gas meter upgrade from the utility, a load management module for big 240-volt appliances, a subpanel, or a Wi-Fi monitor.

The steps

1. 1

   Cause 1: Site survey and load calculation

   A dealer walks the property, checks your panel and gas meter, and decides placement, wiring and piping. Your service size in amps is printed on the main breaker in the panel. Come with a list of what you want running in an outage: well pump, furnace, AC, fridge, sump pump, medical equipment.

   The survey should end with a written estimate that lists the generator size and why.

2. 2

   Cause 2: Choosing the spot

   Placement drives both safety and cost. Champion's guidance is no closer than 18 inches to the house wall where code allows, at least 5 feet from any window, door or vent, and never under a deck. Generac looks for a stable, well-drained spot with room to service the unit.

   Closer to the gas meter and the electric meter means a cheaper install. Champion considers under 20 feet of gas pipe and under 20 feet of wire an optimal run. Think about your bedroom windows and your neighbor's patio too. Generac rates its home units at 65 to 67 decibels, and you'll hear it whenever it runs.

3. 3

   Cause 3: Permits

   Most jobs need an electrical permit and a gas or fuel permit, and HomeAdvisor says most homeowners end up with about two. Generac lists permitting as one of the things that sets the timeline. Check with your local building department, and ask your installer who pulls each permit.

4. 4

   Cause 4: The pad

   The crew levels the site and pours a slab or sets a gravel base. If a concrete pad is needed, HomeAdvisor prices it at $50 to $75 per square foot.

5. 5

   Cause 5: Gas line

   A licensed gas fitter runs pipe from the meter or tank to the generator. On natural gas, the utility may need to swap your meter for a bigger one, and that appointment can be the slowest step in the project. On propane, the tank is set and connected by the propane supplier or the installer.

6. 6

   Cause 6: Transfer switch and wiring

   The electrician mounts the automatic transfer switch next to the main panel and runs wiring to the generator. On a whole-house job, the switch may sit between the meter and the panel. On an essential-circuit job, selected circuits move into the switch.

7. 7

   Cause 7: Startup, testing and inspection

   The dealer starts the unit and simulates an outage to make sure the switch transfers and returns properly. Then the inspector signs off. Ask the installer to walk you through the controls and show you how to shut the unit off.

Mistakes to avoid

• Picking the spot for looks. Hiding it behind a bush that blocks service access, or tucking it under a bedroom window, causes problems for years.
• Skipping the load calculation. HomeAdvisor's advice is to match the generator to your load, because extra capacity only drives up the bill. Undersizing is worse, since the generator trips off when the AC starts.
• Forgetting the gas meter. Ask early if the meter can carry the furnace, water heater, range and generator at once.
• No maintenance plan. Generac recommends service every 6 months. Book the first visit before the installer leaves.

Can you install it yourself?

Not realistically. The job includes gas piping, a transfer switch at the service entrance and an inspection. Generac recommends an authorized dealer or licensed contractor to meet local, state and national codes. A handy homeowner can do the site prep the installer approves, but the gas and electrical work belong to licensed trades.

Portable generators are different. For a portable, "installation" means an interlock kit or a transfer switch plus an outdoor inlet box, still done by an electrician but a much smaller job. See portable generators for home backup.