Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Total generator system cost
$9,400
Generator unit cost
$5,500
Installation labor (pad, electrical, plumbing)
$1,800
Automatic transfer switch
$1,200
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How to use this
- 1Enter generator size.
- 2Enter automatic transfer switch ($).
- 3Enter gas line / propane hookup ($).
- 4Enter pad + electrical/plumbing labor ($).
- 5Read your total generator system cost on the right — it updates as you type.
- 6Hit Share to keep the scenario or send it to someone.
About this calculator
A whole-house standby generator's price scales mainly with output capacity in kilowatts, since larger units that can run a full home's HVAC, well pump, and appliances simultaneously cost significantly more than a smaller unit sized for essential circuits only. This calculator prices the system as a generator unit cost by size, an automatic transfer switch (which safely disconnects from grid power and switches to generator power), a gas line or propane tank hookup, and a concrete pad and electrical/plumbing labor allowance. 2026 US national averages run about $6,000-$9,000 installed for a 14-20kW unit covering essential circuits, and $10,000-$18,000+ for a 22-26kW+ unit sized to run an entire home including central AC. Natural gas hookups are generally cheaper to install than a new propane tank system if gas service already runs to the house; homes without existing gas service need a propane tank (owned or leased) added to the project cost, which isn't included in the base generator pricing here.
Worked example
Using the values the calculator loads with:
Inputs
- Generator size: 14-16 kW (essential circuits) — ~$5,500 unit
- Automatic transfer switch: 1200 $
- Gas line / propane hookup: 900 $
- Pad + electrical/plumbing labor: 1800 $
Results
- Total generator system cost: $9,400
- Generator unit cost: $5,500
- Installation labor (pad, electrical, plumbing): $1,800
- Automatic transfer switch: $1,200
What each field means
Inputs
- Generator size
- Pick the option that matches your situation — the maths changes per option. Choices: 14-16 kW (essential circuits) — ~$5,500 unit, 20-22 kW (most of home) — ~$7,500 unit, 24-26 kW (whole home + AC) — ~$10,500 unit.
- Automatic transfer switch ($)
- The automatic transfer switch used in the calculation, measured in $. Starts at 1200 $ so you have a working example on load. Accepted range: 600–3000 $.
- Gas line / propane hookup ($)
- The gas line / propane hookup used in the calculation, measured in $. Starts at 900 $ so you have a working example on load. Accepted range: 300–3000 $.
- Pad + electrical/plumbing labor ($)
- The pad + electrical/plumbing labor used in the calculation, measured in $. Starts at 1800 $ so you have a working example on load. Accepted range: 800–4000 $.
Results
- Total generator system cost
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Generator unit cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Installation labor (pad, electrical, plumbing)
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Automatic transfer switch
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How do I know what size generator I need?
Sizing depends on your home's total electrical load — an electrician performs a load calculation factoring in HVAC, well pump, and major appliances; as a rough guide, 14-16kW covers essential circuits for most homes, while 22kW+ is typically needed to run central air conditioning simultaneously with everything else.
Natural gas or propane — which is better for a standby generator?
Natural gas is generally preferred when available since it draws from an unlimited utility supply and needs no tank refills, while propane requires either an owned or leased tank that needs periodic refilling but works anywhere, including homes without gas utility service.
Is a permit required for a whole-house generator?
Yes, in virtually all US jurisdictions — the installation involves both electrical work (the transfer switch) and often gas or propane plumbing, both of which require permits and inspection to ensure the system won't backfeed power to utility lines and endanger repair crews.
How often does a standby generator need maintenance?
Most manufacturers recommend an annual service including oil change, filter replacement, and a battery/functional test, plus most units run a brief self-test weekly on their own — skipping maintenance is the leading cause of a generator failing to start during an actual outage.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Whole-House Generator Cost Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/whole-house-generator-cost
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/whole-house-generator-cost" target="_blank" rel="noopener">Whole-House Generator Cost Calculator — RevenueLab</a> (2026).</p>
Source: [Whole-House Generator Cost Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/whole-house-generator-cost) (2026).