Whole House Generator Cost: $4,000–$25,000 (Average $9,000) in 2026
Author: CostGuideHQ Editorial·✓ Fact-checked·Updated July 2026·5 min read·5 sources Quick answerQuick answer: A fully installed whole house generator costs $4,000 to $25,000, averaging around $9,000 (Forbes Home). Equipment alone runs from $500 for a small portable unit to over $21,000 for a large standby system, with installation labor adding another $1,500 to $5,000 (HomeAdvisor, Bob Vila).
- ✓Most homeowners pay around $9,000 for a fully installed whole house generator, with typical projects ranging from $4,000 to $25,000 (Forbes Home).
- ✓A mid-size 20-24 kW standby unit, enough for most homes' main systems, costs $5,000 to $6,500 for equipment alone before installation (HomeAdvisor, Bob Vila).
- ✓Installation labor typically adds $1,500 to $5,000 on top of the generator's price (Forbes Home, HomeAdvisor, Bob Vila).
- ✓An automatic transfer switch costs $2,000 to $30,000 installed, versus $500 to $2,000 for a manual switch (HomeAdvisor).
How much does whole house generator cost?
National average
$9,000
total project
Typical range
$4,000–$25,000
Most projects
Whole project
$6,000–$20,000
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Cost by material / type
| Type | Low | High |
|---|
| 1-6 kW (portable/small backup) | $500 | $1,800 |
| 7.5-10 kW | $2,000 | $3,500 |
| 14-18 kW | $4,000 | $5,500 |
| 20-24 kW | $5,000 | $6,500 |
| 26-32 kW | $6,500 | $15,000 |
| 36-38 kW | $14,000 | $16,000 |
| 45-48 kW | $16,200 | $21,000 |
What affects the cost?
- Generator size (kW), based on whether you're backing up essential circuits or the whole home's electrical load
- Fuel type: natural gas and liquid propane units run $2,000-$21,000, diesel $3,000-$20,000, gasoline (portable only) $500-$3,000 (HomeAdvisor, Bob Vila)
- Transfer switch type: an automatic transfer switch runs $2,000-$30,000 installed versus $500-$2,000 for a manual switch (HomeAdvisor)
- Concrete or composite pad for the unit, about $50-$75 per square foot (HomeAdvisor, Bob Vila)
- Electrical panel or subpanel upgrades, roughly $500-$2,000 (HomeAdvisor, Bob Vila)
- Permits, typically $50-$200 each (HomeAdvisor, Bob Vila)
- Professional installation labor, generally $1,500-$5,000 on top of the unit price (Forbes Home, HomeAdvisor, Bob Vila)
- Home size and number of circuits or appliances you want backed up
- Brand, warranty length, and local contractor rates
- Ongoing maintenance, roughly $80-$500 per year (HomeAdvisor, Fixr)
Why does a whole house generator cost so much?
A whole house generator isn’t just the unit itself. You’re paying for a piece of equipment sized to your home’s electrical load, plus the labor, wiring, and permitting to tie it into your house safely. Fully installed, most homeowners land around $9,000, with typical projects spanning $4,000 to $25,000 (Forbes Home). The generator alone can range from $500 for a small portable-style unit up to $21,000 or more for a large standby system in the 45-48 kW class (HomeAdvisor, Bob Vila). On top of that, installation labor usually adds another $1,500 to $5,000 (Forbes Home, HomeAdvisor, Bob Vila). Larger homes need bigger units to cover more circuits, and bigger units cost more both to buy and to install, which is why the spread between a modest setup and a full-house system is so wide.
What affects the cost?
- Generator size (kW). This is the single biggest driver. A 14-18 kW unit for critical systems runs $4,000-$5,500, while a 20-24 kW unit for main systems runs $5,000-$6,500, and 26-32 kW units for larger homes run $6,500-$15,000 (HomeAdvisor, Bob Vila).
- Fuel type. Natural gas and liquid propane units each span roughly $2,000-$21,000 depending on size; diesel runs $3,000-$20,000; gasoline-powered portable units run $500-$3,000 (HomeAdvisor, Bob Vila).
- Transfer switch. A manual transfer switch costs $500-$2,000 installed, while an automatic transfer switch (which switches over without you flipping anything) runs $2,000-$30,000 (HomeAdvisor).
- Concrete pad. Standby units sit on a pad, typically priced at $50-$75 per square foot (HomeAdvisor, Bob Vila).
- Electrical work. Panel or subpanel upgrades run $500-$2,000, and permits typically cost $50-$200 each (HomeAdvisor, Bob Vila).
- Installation labor. Professional installation generally adds $1,500-$5,000 to the total, with larger units taking longer and costing more to install (Forbes Home).
- Home size and circuit count. The more of your home’s systems you want backed up, the larger (and pricier) the generator and wiring job.
How to lower your whole house generator cost
- Size the generator to your needs, not your whole panel. Backing up essential circuits with a 7.5-10 kW unit ($2,000-$3,500) costs far less than a full-house 26-32 kW system ($6,500-$15,000) (HomeAdvisor, Bob Vila).
- Compare a manual transfer switch against automatic. A manual switch can save thousands over an automatic one ($500-$2,000 versus $2,000-$30,000), if you’re comfortable manually switching over during an outage (HomeAdvisor).
- Get multiple installation quotes. Installation labor alone ranges $1,500-$5,000 (Forbes Home, HomeAdvisor, Bob Vila), so pricing out two or three local electricians can meaningfully change your total.
- Ask about existing electrical panel capacity. If your panel already supports the new load, you may avoid the $500-$2,000 panel upgrade cost (HomeAdvisor, Bob Vila).
- Budget for annual maintenance up front. At $80-$500 a year (HomeAdvisor, Fixr), factoring this into your decision helps you compare the true long-term cost of different generator sizes, not just the sticker price.
Prices vary by region, home size, and fuel availability, so treat the figures above as a planning budget. Get quotes from two or three licensed local electricians or generator installers, and confirm what size unit each one recommends, before committing to a final number.
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Frequently asked questions
How much does a whole house generator cost installed?+
A fully installed whole house generator typically costs $4,000 to $25,000, averaging about $9,000 (Forbes Home). HomeGuide reports a similar installed range of $6,000 to $11,000, while Fixr's estimate for larger standby systems runs $10,000 to $20,000.
What size generator do I need for my whole house?+
For most homes running main systems (roughly 3,000-5,000 sq ft), a 20-24 kW unit is common and costs $5,000 to $6,500 for equipment alone. Smaller homes can get by with a 14-18 kW unit ($4,000-$5,500), while larger homes with heavy appliance loads may need 26-32 kW or more ($6,500-$15,000) (HomeAdvisor, Bob Vila).
Does the cost include the concrete pad and transfer switch?+
Not usually. The generator unit price and installation labor are the two biggest line items, but a concrete pad ($50-$75 per square foot), a transfer switch ($500-$2,000 manual, or $2,000-$30,000 automatic), an electrical panel upgrade ($500-$2,000), and permits ($50-$200 each) are typically quoted separately (HomeAdvisor, Bob Vila).
Is natural gas or propane cheaper for a whole house generator?+
Equipment cost is similar for both: natural gas and liquid propane units each run about $2,000 to $21,000 depending on size (HomeAdvisor, Bob Vila). Daily operating costs differ more: Bob Vila cites roughly $90 a day to run a 21 kW natural gas unit versus about $220 a day for a 20 kW propane unit.
How much does it cost to maintain a whole house generator?+
Annual maintenance typically runs $80 to $500 a year, depending on the source and service plan (HomeAdvisor, Fixr).
Why do generator cost estimates vary so much between sites?+
HomeAdvisor and Bob Vila report lower national averages (around $5,090-$5,160) because their data blends in small portable units starting at $500. Forbes Home, Fixr, and HomeGuide focus on fully installed automatic standby systems, which is why their averages run higher, from about $9,000 to $15,000.
Sources
Figures synthesized and cross-checked across these sources (retrieved 2026-07-24):
- Fixr — National average cost $15,000; average range $10,000-$20,000. Low-end $900 (portable 5kW), high-end $25,000 (25kW standby). By size (material only): 5-6kW $600-$2,000; 7-12kW $800-$4,000; 13-16kW $3,500-$5,000; 17-21kW $4,500-$7,000; 22-25kW $6,000-$10,000; 30-38kW $10,000-$20,000. By fuel: propane $500-$20,000; natural gas $2,000-$20,000; gasoline/diesel (portable) $500-$2,000; solar $1,500-$5,000. Installation costs start around $5,000, up to $11,000 on the high end, typically $5,000-$6,000 for labor. Transfer switch installation $2,700-$3,700 total. Electrical wiring $1,000-$2,000. Annual operating cost $0-$500. Maintenance $200-$500/year.
- HomeAdvisor — Average cost $5,160; typical range $1,516-$8,811; possible range $350-$13,500. By capacity: 1-6kW (portable) $500-$1,800; 7.5-10kW (essential systems, homes under 1,500 sq ft) $2,000-$3,500; 14-18kW (critical systems, 1,500-3,000 sq ft) $4,000-$5,500; 20-24kW (main systems, 3,000-5,000 sq ft) $5,000-$6,500; 26-32kW (large homes) $6,500-$15,000; 36-38kW $14,000-$16,000; 45-48kW (commercial-grade) $16,200-$21,000. By fuel: natural gas $2,000-$21,000; liquid propane $2,000-$21,000; diesel $3,000-$20,000; gasoline $500-$3,000; solar $2,000-$25,000; battery backup $10,000-$25,000. Installation labor $1,500-$5,000. Concrete pad $50-$75/sq ft (about $1,000 for an 18 sq ft pad). Manual transfer switch $500-$2,000; automatic transfer switch $2,000-$30,000. Electrical panel upgrade $500-$2,000. Permits $50-$200 each. Annual maintenance $80-$300.
- Bob Vila — National average $5,090; typical cost range $1,524-$8,658. By size (unit only): 1-6kW $500-$1,800; 7.5-10kW $2,000-$3,500; 14-18kW $4,000-$5,500; 20-24kW $5,000-$6,500; 26-32kW $6,500-$15,000; 36-38kW $14,000-$16,000; 45-48kW $16,200-$21,000. By fuel (unit only): diesel $3,000-$20,000; gasoline $500-$3,000; liquid propane $2,000-$21,000; natural gas $2,000-$21,000; solar $2,000-$25,000. Installation labor $1,500-$5,000. Concrete pad installation $50-$75/sq ft. Permits $50-$200 each. Electrical subpanel $530-$2,000. Dedicated circuit installation $500-$1,000. Daily operating cost: natural gas (21kW) about $90/day; propane (20kW) about $220/day; diesel (20kW) $175/day on average.
- Forbes Home — Whole-house generators range from $4,000 to $25,000 or more, but most homeowners pay around $9,000 including installation. Installation alone runs $1,500 to $5,000, with large generators taking longer and costing more to install than small generators.
- HomeGuide — Whole house generators cost $6,000-$11,000 with installation.
Sources split into two clusters. HomeAdvisor and Bob Vila (which closely mirror each other) report a lower blended national average of about $5,090-$5,160 with a typical range of $1,516-$8,830, because their figures include small portable and near-portable units (1-6 kW) alongside true whole-house standby systems. Fixr, Forbes Home, and HomeGuide focus on fully installed automatic standby systems and report meaningfully higher figures: Fixr's average is $15,000 ($10,000-$20,000 typical range, full range $900-$25,000+), Forbes Home's average is about $9,000 ($4,000-$25,000+ range, with installation labor alone at $1,500-$5,000), and HomeGuide puts installed whole-house systems at $6,000-$11,000. This guide uses Forbes Home's $9,000 average and $4,000-$25,000 range as the headline figures since they best represent a fully installed automatic standby system (the common meaning of 'whole house generator') without folding in bare portable-unit pricing. The project_low/project_high band ($6,000-$20,000) reflects the tighter typical range where HomeGuide's low end and Fixr's typical high end overlap. The by_type table lists equipment-only pricing by generator size from HomeAdvisor and Bob Vila (which agree closely); installation labor, the pad, transfer switch, and permits are added on top and are covered in cost_factors.