Methodology
Visible assumptions, replaceable evidence.
The model starts with 2026 equipment bands for 14–26 kW gaseous standby generators, adds a core installation allowance, then itemizes the automatic transfer switch, new fuel-line length, propane tank, subpanel, pad and permit choices. Straightforward and complex installation anchors come from current market evidence; the middle band is an explicit planning interpolation. No hidden fuel or regional multiplier is used.
How the model works
- Generator capacity is an entered price scenario, not a sizing recommendation.
- Equipment, core installation and selected additions remain separate in the result.
- The 14–18, 20–24 and 26–32 kW equipment bands come from current 2026 observations and are mapped to the selectable sizes.
- The core installation bands expose straightforward, modeled typical and long/complex scope instead of multiplying the entire project.
- Fuel-line length uses a current $15–$50+ per-foot planning band but never certifies pipe or utility capacity.
- Transfer switch, propane tank, subpanel, pad and permits can be removed when already included, preventing obvious double counting.
- Sizing, fuel pressure, electrical design, clearances, permits and commissioning remain professional decisions.
What the result means
The low and high values are planning bounds. The midpoint is simple arithmetic, not a prediction of the most likely contractor or carrier price. The calculator cannot inspect a property, verify a shipment, choose a legally suitable system, reserve capacity or issue a quotation.
Review date: 14 September 2026. We change a model only when the source, calculation and reason for the change can be recorded.
Current evidence snapshot
These dated US observations bound a transparent planning model. They are not additive unless the selected item is outside the quoted package, and they do not replace a local load calculation, fuel design, permit review or installed proposal.
- Typical whole-house system: $6,000–$11,000 installed
HomeGuide's current average range for a whole-house generator and installation.
- Long route or over 20 kW: $9,500–$24,000 installed
HomeGuide's separate high-scope range showing why size and routing cannot be hidden in one average.
- Generac complete-system statement: $8,000–$16,000 total
Manufacturer sizing page statement including generator, system equipment, materials and installation.
- 14–18 kW equipment: $4,000–$5,500 unit only
Angi's September 2026 capacity band, before installation.
- 20–24 kW equipment: $5,000–$6,500 unit only
Angi's September 2026 capacity band, before installation.
- 26–32 kW equipment: $6,500–$15,000 unit only
Angi's September 2026 capacity band; larger equipment creates a materially wider range.
- Current Generac 14 kW example: $4,889 MSRP
Manufacturer starting MSRP for generator-only cellular model 7258; packages with switches differ.
- Current Generac 18 kW example: $5,709 MSRP
Manufacturer starting MSRP for generator-only cellular model 7259; packages with switches differ.
- Current Generac 22 kW example: $6,309 MSRP
Manufacturer starting MSRP for generator-only cellular model 7260; packages with switches differ.
- Current Generac 26 kW example: $7,159 MSRP
Manufacturer starting MSRP for generator-only cellular model 7327; packages with switches differ.
- Automatic transfer switch: $600–$2,500 installed
HomeGuide's current automatic-switch observation.
- New fuel line: $15–$50+ per foot
HomeGuide's current gas-line planning range; pipe sizing and capacity still require design.
- Propane tank: $400–$1,800 installed
HomeGuide's current project-component observation; tank size, ownership and burial can change it.
- Pad and permits: $150–$400 / $80–$450
HomeGuide's current separate pad and permit observations.
- Annual maintenance: $200–$650
HomeGuide's January 2026 whole-house maintenance-plan observation.
Source register
- HomeGuide whole-house generator cost guide
December 2025 current installed, unit, labor, size and project-component observations; reviewed 14 September 2026.
- Angi whole-house generator cost guide
September 2026 capacity, equipment and installation observations; reviewed 14 September 2026.
- Generac home-generator sizing and cost guide
Manufacturer sizing inputs and current $8,000–$16,000 complete-system statement; reviewed 14 September 2026.
- Generac 14 kW product page
Current unit-only MSRP and model fuel-consumption example; reviewed 14 September 2026.
- Generac 18 kW product page
Current unit-only MSRP and model fuel-consumption example; reviewed 14 September 2026.
- Generac 22 kW product page
Current unit-only MSRP and model fuel-consumption example; reviewed 14 September 2026.
- Generac 26 kW product page
Current unit-only MSRP and model fuel-consumption example; reviewed 14 September 2026.
- HomeGuide transfer-switch cost guide
Current automatic, manual and interlock installed-price observations; reviewed 14 September 2026.
- HomeGuide generator repair and maintenance guide
January 2026 maintenance, repair and service-call observations; reviewed 14 September 2026.
- CPSC generator safety guidance
Official portable-generator carbon-monoxide safety boundary; reviewed 14 September 2026.
- FEMA manual transfer-switch guidance
Official grid-isolation and backfeed explanation; reviewed 14 September 2026.
Error corrections
If a source is outdated or a calculation does not behave as described, email [email protected] and identify the URL, input and expected result. Do not include private customer or property information.