Generator installers send a written estimate after a site visit, and often the client collects two or three to compare. Clients look at brand and kW size, what the transfer switch covers, gas versus propane, and who handles permits and the utility. A clear scope separates a fair bid from a low one that leaves out gas work or the pad.
When to use estimates: Use estimates to provide project quotes and get client approval before starting work. Once approved, convert your estimate to an invoice with one click to collect payment.
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Invoice_1001_Client_2026-10-14.pdf
Two bids at different sizes or brands are not comparable, and the load calculation should justify the size you chose.
Whole-home, service-entrance and selected-circuit setups differ greatly in price and clients often assume more is covered.
State fuel type, pipe material, estimated footage, who supplies the propane tank, and whether a meter or regulator upgrade is needed from the utility.
Pad location, setbacks and distances to the panel and gas meter drive trenching and wiring costs. Note the assumed footage so overages are clear.
Say who pulls permits and who pays fees, and note that HOA or utility approval timelines can delay the start.
List items such as panel upgrades, rock excavation, landscaping repair, tree removal, driveway or patio cutting and propane fill, which otherwise get assumed as included.
Equipment prices and delivery times change. State how long the quote holds, the expected schedule, and the deposit and progress payments.
| Service | Priced | Typical range |
|---|---|---|
| Standby generator install labor (residential, 10-24 kW), unit not included | flat fee | $3,000-7,500 |
| Generator unit, 22 kW air-cooled (supplied by contractor) | each | $4,500-7,500 |
| Automatic transfer switch (100-200 amp) supply and install | each | $900-2,500 |
| Gas line extension (natural gas or propane), black iron or CSST | per linear foot | $15-45 |
| Electrical conduit and wire run, trenching included | per linear foot | $20-60 |
| Concrete or composite equipment pad | flat fee | $300-900 |
| Permit and inspection coordination | flat fee | $150-600 |
| Electrician or gas fitter labor, service and repair | per hour | $85-175 |
| Annual maintenance plan (oil, filters, plugs, load test) | per visit | $200-450 |
Typical US ranges. Rates vary by region, experience, and job size.
Size the unit from the panel's actual loads rather than a guess. It supports your price and avoids callbacks for an undersized unit.
Include an assumed footage for gas and electrical runs and a per-foot rate for anything beyond it. The client sees how the number was built and overages are simple to explain.
Present two or three configurations, such as a smaller unit with a selected-circuit switch versus a larger unit with a whole-home switch, so the client chooses a scope rather than a bidder.
Set a short validity window, often 14 to 30 days, and say that equipment price changes from the manufacturer may adjust the quote after that.
Many installers do free site visits for standard residential jobs. Some charge a fee of $100 to $300 for complex or commercial work and credit it toward the job if the client signs.
A flat quote holds for the stated scope and assumptions. Anything outside it, like extra footage or rock, is handled by change order. Write that into the estimate.
Typically 14 to 30 days. Equipment costs and availability can shift, so a short window protects you.
Yes, if it includes scope, price, payment schedule and signature lines and meets your state's contractor requirements. Many states require specific language, such as cancellation rights or license numbers, so check local rules.
Use the Generator Installation invoice template to bill the client, or convert this estimate once it's approved.
Generator Installation invoice template