What the job actually involves
A standby generator installation is two trades and a set of approvals, which is why quotes vary so much more than the equipment does.
- A site survey. Where the unit goes, how far from the panel and the gas supply, and what the clearances allow.
- A load calculation. Against your actual panel and appliances, which determines the size and whether load management is needed.
- Permits. Typically electrical and mechanical or gas, sometimes a zoning or noise review.
- A pad. Concrete or a composite base, level and drained.
- Electrical work. The automatic transfer switch, a feeder to the panel, and either whole-panel or sub-panel wiring.
- Gas work. A branch from the main with correct pipe sizing, or a propane tank sited, set and connected.
- Commissioning. First start, configuration, the break-in check, and setting the exercise schedule.
- Inspection. By the authority having jurisdiction, before it is signed off.
Steps 5 and 6 are where quotes diverge most, and they are the two most worth asking about in detail.
What drives the cost
| Factor | Why it moves the price |
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| Distance from panel and gas supply | Every extra foot is conduit, trenching and pipe. The single biggest controllable variable |
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| Gas pipe sizing | A standby unit is a large gas appliance; existing pipe often has to be upsized back toward the meter |
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| Whole-panel vs sub-panel switch | A whole-panel automatic transfer switch costs more than a selected-circuit sub-panel |
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| Load management modules | Adds cost, but often lets you buy a smaller generator — usually a net saving |
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| Propane tank | Siting, setbacks, the tank itself and the first fill |
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| Ground conditions | Rock, a high water table or a long trench across a driveway all add real hours |
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| Permits and inspection | Vary enormously by jurisdiction |
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We do not publish installed-price figures for standby systems, because the range across regions and site conditions is wide enough that any single number would mislead more than it helps. Get two or three local quotes; the spread between them is itself informative. Transfer switch installation costs covers the portable equivalent, where the numbers are tighter.
Siting: the decision you make once
- Close to both the panel and the gas supply. Every foot of separation is money. If the two are on opposite sides of the house, that is worth knowing before you fall in love with a location.
- At the manufacturer's and code's required clearances from windows, doors, vents and combustible walls. Your installer knows these; ask what they are for your unit.
- Exhaust pointed away from the house, and away from any HVAC outdoor air intake.
- Above likely flood level and off a low spot. Flooding and outages arrive together.
- Where snow will not drift against it, and where you can reach it to clear leaves.
- Away from bedroom windows — yours and the neighbors'. The weekly exercise cycle runs for years.
- Accessible for service. A unit boxed in by later landscaping is a unit that gets serviced badly.
Whole-panel or selected circuits
The choice that most affects both cost and behavior, and it is worth understanding before the survey.
A whole-panel automatic transfer switch backs up the entire service. Everything works and nothing has to be chosen in advance. It costs more and it usually requires a larger generator, or load management to stop everything starting at once.
A sub-panel carries a chosen set of circuits. Cheaper, allows a smaller generator, and forces a useful conversation about what actually matters. The cost is that anything not on the list stays dark.
The circuit most often left off by accident is the well pump, because it is not in the kitchen and does not feel like an appliance. On a well, that is the circuit that matters most.
The permit is not optional
Every part of this is permitted work in most jurisdictions — the electrical connection, the gas connection, and often the placement itself. Three reasons that matters beyond compliance:
- Insurance. Unpermitted work on gas and electrical systems can affect a claim, including claims unrelated to the generator.
- Selling the house. Unpermitted installations surface during a sale and get expensive at the worst moment.
- The inspection catches things. It is a second professional looking at gas sizing, bonding and clearances. That is worth having.
An installer who suggests skipping the permit is telling you something about the rest of their work.
Timeline, and why it is longer than you expect
The physical work is usually a couple of days. The calendar is not.
- Survey and quote: days to a couple of weeks.
- Permits: the main variable, and entirely outside your installer's control.
- Equipment lead time: normally short, and then suddenly months after a major regional outage, because everyone orders at once.
- Utility coordination if a gas meter needs upgrading.
- Inspection scheduling after the work.
Which is the practical advice this page exists to give: start in the spring, not after the storm. Demand, pricing and lead times all move against you in the weeks after a widespread outage.
Questions to ask before signing
- Which fuel is the quoted kW rating for? Units are rated differently on natural gas and propane — Generac publishes 21kW and 24kW for the same Guardian.
- Can I see the load calculation? Not the recommendation — the working.
- Does the quote include gas pipe upsizing? The most common source of a change order.
- Whole panel or sub-panel, and which circuits?
- Are permits and inspection included in the price?
- Who does the break-in service, and is it included? Generac specifies it at the first 25 hours of runtime, which arrives sooner than owners expect.
- What does the warranty require of me? Coverage is generally conditional on documented maintenance.
- What is the annual service contract, and what is in it?
After it is commissioned
- Set the exercise schedule to a weekday daytime slot. It runs for years; the neighborhood will notice a Sunday morning one.
- Watch for the break-in service. The weekly exercise accumulates hours in the background — fifteen minutes a week is about thirteen hours a year, so 25 hours arrives inside two years even without an outage.
- Note where the manual disconnect is and how to shut the system down. Find this out on a calm day.
- Test the alarms and check the exhaust path once the landscaping settles.
The maintenance schedule covers the intervals, and the sizing guide covers the decision this all follows from.
