A whole-house standby generator installed in 2026 realistically costs $9,600 to $14,300 for a 24kW unit. You will see averages closer to $5,160 quoted widely. That figure is lower than the price of the equipment alone, and we will show you exactly why.
Why the published averages do not add up
| Source | Claim |
|---|---|
| Angi (updated 1 Sep 2026) | $350–$13,500, average $5,160; most pay $1,516–$8,810 |
| HomeAdvisor | $1,516–$8,810, average $5,160 — identical to Angi, same parent company |
| HomeGuide | $6,000–$11,000 installed; unit $3,000–$6,000, labour $3,000–$5,000 |
Now hold that $5,160 average against a number we pulled from Generac’s own live pricing: a 24kW unit with transfer switch lists at $7,789 — hardware only, before anyone digs a trench. An average that sits below the bare equipment cost tells you the sample is diluted with portable generators, small essential-circuit jobs and transfer-switch-only work.
Our $9,600 to $14,300 figure is arithmetic, not a survey: $7,789 in hardware, plus $1,500 to $5,000 in labour, plus $150 to $1,000 for the pad, plus $80 to $450 in permits, plus the gas line. We could not find a single authoritative national average for a genuine whole-house install, and we would rather say that than invent one.
What the units actually cost
| Size | Unit only | Unit + transfer switch |
|---|---|---|
| 10kW | $3,769 | $4,619 |
| 14kW | $4,889 | $5,949 |
| 18kW | $5,709 | $6,769 |
| 22kW | $6,309 | $7,369 |
| 24kW | $6,729 | $7,789 |
| 26kW | $7,159 | $8,219 |
| 28kW | $8,159 | $9,509 |
Retail can beat MSRP slightly. Home Depot lists the Generac 72101 at $7,259 against a $7,399 MSRP for the same unit. Kohler’s 26RCAL starts at $8,515 with the transfer switch included, roughly $300 above Generac’s 26kW.
One caution on Angi’s installed-cost-by-size table, which puts a 20–24kW job at $5,000 to $6,500: the 24kW unit alone lists at $6,729 to $7,789. That table cannot be right, and you should not plan around it.
Do you actually need to power the whole house?
Usually no, and the code gives you a cheaper legal path. Under NEC 702.4(A)(2), an automatically-connected standby system either supplies the entire connected load, or uses an energy management system, in which case the generator only needs capacity for the maximum load the EMS will permit.
That second path is where the money is. A 22kW unit with load-management modules shedding the second AC compressor and the electric range will comfortably run a house that on paper “needs” 30kW or more. HomeGuide puts a 1,500 to 3,000 square foot home at 17 to 20kW, which is why the 18kW and 22kW units are the volume sellers.
The step from 22kW to 26kW is $850 in hardware. The step from air-cooled to liquid-cooled above 28kW is a different category of money and a different service regime entirely.
The installation, line by line
| Item | Cost |
|---|---|
| Concrete pad | $150–$400 (HomeGuide) or ~$1,000 (HomeAdvisor) |
| Automatic transfer switch, installed | $600–$2,500 |
| Manual transfer switch, installed | $400–$1,300 |
| Interlock kit, installed | $400–$850 |
| Gas line | $12–$25 per foot |
| Electrical labour | $1,500–$5,000 |
| Permits | $80–$450, or $50–$200 each |
The pad figures differ by six times between two sources owned by the same company. That gap is almost certainly a poured pad with excavation versus a pre-cast composite base, which is what Generac units are designed to sit on. Get it itemised.
The gas line is the most under-quoted item on most bids. At $12 to $25 a foot, a 60-foot run to a side yard is $720 to $1,500 in pipe alone. The trap is capacity: a 24kW unit consuming 197 cubic feet an hour at half load often exceeds what an existing residential meter and a half-inch or three-quarter-inch branch line can deliver at the required inlet pressure. That triggers a utility meter upgrade and a resized trunk line. Ask about this before you sign, not after the inspector fails you.
Natural gas, propane, or diesel
The derating nobody puts in the headline
This is real, it is substantial, and the number on the box is the propane number.
| Model | Rated kW on propane | Actual kW on natural gas | Derate |
|---|---|---|---|
| 10kW (7171) | 10 | 9 | −10% |
| 14kW (7223) | 14 | 14 | 0% |
| 18kW (7226) | 18 | 17 | −5.6% |
| 22kW (7042) | 22 | 19.5 | −11.4% |
| 24kW (7209) | 24 | 21 | −12.5% |
| 26kW (7290) | 26 | 22.5 | −13.5% |
Kohler is the same story: the 26RCAL is 26kW on propane and 24kW on natural gas. The derate is shrinking on newer models — Generac’s current 72610 lists 22.5kW on gas against 24kW on propane, better than the older 7209 — so check the specific model number rather than assuming a brand-wide figure.
If you are on natural gas, size up one step, or verify the model’s gas rating before signing.
What it costs to run
| Unit | Fuel | Consumption at half load | Cost per hour | Per day |
|---|---|---|---|---|
| 14kW | Natural gas | 189 cu ft/hr | $4.55 | ~$109 |
| 14kW | Propane | 1.76 gal/hr | $4.70 | ~$113 |
| 24kW | Natural gas | 197 cu ft/hr | $4.75 | ~$114 |
| 24kW | Propane | 2.45 gal/hr | $6.54 | ~$157 |
Propane costs roughly 38 per cent more per hour than natural gas on the 24kW at half load. Over a five-day outage that is about $785 against $570.
One honest flag on the data: Generac’s own pages give the 14kW as burning 189 cubic feet an hour on gas while the 24kW burns 197. A 14kW using nearly as much fuel as a 24kW is implausible, and is likely a specification error or a different measurement basis. We are reporting it as published, but would not build a budget on the 14kW gas figure.
Propane tank sizing
Tanks fill to 80 per cent, so a 500-gallon tank holds 400 usable gallons. At 2.45 gallons an hour on a 24kW at half load, that is about 163 hours, or 6.8 days. A 250-gallon tank gives roughly 3.4 days.
A 500-gallon tank is the practical minimum for a whole-house unit, and 1,000 gallons is what you want if you are rural. Installed cost runs $700 to $4,500, with about $1,500 typical for a 500-gallon above-ground tank and $2,000 buried. Leasing runs $50 to $200 a year.
How each fuel behaves when the region goes dark
- Natural gas. The underground network usually keeps flowing through wind and ice events, which means unlimited runtime and no refuelling. It fails in earthquakes, when utilities shut the mains, and can be curtailed during extreme cold-snap demand. If your gas is curtailed, your generator is a lawn ornament.
- Propane. Independent of both grids, which is why it dominates rural installs. The failure mode is logistical: in a multi-county event, delivery trucks back up for days and roads may be blocked. Top off before the storm, not after. A small tank in deep cold also cannot vaporise fast enough to feed a large load — a second reason to oversize.
- Diesel. Effectively not a residential product in 2026. Neither Generac’s nor Kohler’s residential lineup lists an air-cooled diesel home unit; diesel starts at liquid-cooled 30kW and up, and brings fuel storage, gelling, algae and noise with it.
The much cheaper option: a portable and an interlock kit
A 12,000 watt dual-fuel portable with electric start lists at $1,299 at Home Depot. An interlock kit installed runs $400 to $850. All in, roughly $1,700 to $2,150 against $9,600 to $14,300 for standby. That is a genuine six-to-eight-times saving and it is the right answer for a lot of households.
Here is what you honestly give up:
- Automation. No auto-start. If the power fails at 2am, or while you are at work, or while you are away, nothing happens. Frozen pipes and a dead sump pump do not wait for you.
- Manual labour every time. Wheel it out, connect the inlet cord, start it, go to the panel, kill the main, slide the interlock, switch on your chosen breakers — and reverse all of it when utility power returns.
- Refuelling every 8 to 12 hours, in the storm. On petrol especially: you are storing jerry cans, and stations without power cannot pump. This is what ends most portable plans by day three.
- Manual load management. 9,500 watts on propane will not run central AC plus a well pump plus a range. You are the load-shedding controller, and you have to walk to the panel.
- The same derate in reverse. That unit is 12,000 watts on petrol and 9,500 on propane — a 21 per cent cut for the fuel that stores safely.
- Carbon monoxide risk. Portables kill people every storm season. They run well clear of the house, never in a garage, even an open one.
- You still need an electrician. The interlock and inlet box are permitted electrical work. Backfeeding through a dryer outlet is illegal, can kill a lineworker, and voids your insurance.
A middle option worth knowing: a manual transfer switch at $400 to $1,300 installed gives you a dedicated labelled subpanel, which is cleaner and harder to get wrong than an interlock.
What about a home battery instead?
Read this first: the federal battery tax credit is gone
This is the single most important thing on this page, and a great many installer websites are still getting it wrong in September 2026.
The credit is not available for any property placed in service after December 31, 2025.
IRS, Residential Clean Energy Credit (Section 25D)
Battery storage of 3kWh or more was eligible under Section 25D from 2023 through 2025. It is not eligible now. There is no 30 per cent, no phase-down, no reduced rate.
Two details that catch people out. First, paying in 2025 does not preserve the credit — what controls is when installation was completed. A battery paid for in December 2025 but commissioned in January 2026 gets nothing. Second, standby generators were never eligible for this credit at any point. Any site telling you a Generac qualifies for a federal energy credit is simply wrong.
A word on why the confusion persists: the IRS page itself still carries stale legacy text saying the credit phases out in 2033, directly contradicting the operative sentence on the same page. If you are checking this yourself, the line that governs is the one about property placed in service after 31 December 2025.
There may be a remaining route under third-party ownership, where a leasing company claims a commercial credit and passes the benefit through as lower payments. We could not verify that against an IRS or Treasury source, so treat it as something to get in writing from your installer and check with a tax professional — not as a fact. And under a lease, you do not own the battery.
State and utility programmes such as California’s SGIP and various utility virtual power plant schemes may still be substantial, and are now the primary incentive. We did not verify any specific programme’s 2026 status.
What batteries cost
| Brand | Per kWh installed | Example system |
|---|---|---|
| Tesla Powerwall | $967 | $13,055 for 13.5 kWh |
| Enphase | $1,429 | $14,290 for 10 kWh |
| FranklinWH | $1,232 | $18,480 for 15 kWh |
| Market average | — | $15,650 for a typical 13.5 kWh system |
Worth noting: Tesla publishes no price, no capacity, no power rating and no warranty length on its Powerwall page — it routes you to a consultation. Neither do Enphase or FranklinWH. There is no manufacturer list price for any of these. Anyone quoting a precise Powerwall figure is quoting an installer.
Which one is right for you
| A battery wins when | A generator wins when |
|---|---|
| Outages are short and frequent | Outages last days |
| You have or plan solar to recharge it | You have natural gas at the meter |
| Noise, HOAs or ordinances are an issue | You need to run central AC |
| You want daily value: time-of-use arbitrage, solar self-consumption, utility VPP payments | You want indefinite runtime |
| You want zero maintenance | Deep cold is a factor |
The fact most often glossed over: without solar, a battery cannot recharge during an outage. Battery-only with no panels is a one-shot device. Once it is flat you wait for the grid. And 13.5kWh is roughly one day of conservative essentials, far less with air conditioning running. A 24kW generator on natural gas runs indefinitely.
The loss of the tax credit in 2026 shifted this comparison meaningfully toward generators. A $15,650 battery that effectively cost $10,955 in 2025 costs $15,650 today.
Running costs, warranty and maintenance
Both Generac and Kohler offer a five-year limited warranty, verified on their live product pages. They are not differentiated on warranty length — only on service network radius, where Kohler claims dealer coverage to 200 miles against a stated competitor 100 miles. These are limited warranties, so coverage narrows in later years; we did not obtain the year-by-year schedules.
| Ongoing cost | Figure |
|---|---|
| Annual maintenance (Angi) | $200–$600 |
| Annual maintenance (HomeAdvisor) | $80–$300 |
| Per service visit | $171–$395, average $273 |
| Stator or rotor repair | $250–$1,500 |
| Transfer switch repair | $50–$400 |
| Remote monitoring hardware | $200–$400 |
On maintenance intervals, Generac’s own support page declines to publish them, saying only that owners should reference their user manual for maintenance intervals, tasks and required parts. It lists the tasks — oil and filter, air filter, spark plugs, valve adjustment, fuel leak inspection, battery check, sediment trap — but no hours or months. Anyone telling you “Generac requires an oil change every 200 hours” is quoting one model’s manual, not a brand rule.
The recurring cost nobody budgets for is the exercise cycle. Standby units self-test weekly or fortnightly, year-round, whether or not the power ever fails. Generac’s Quiet-Test runs at 55 to 57 dB(A) against 61 to 67 under load; Kohler lists 56 dB(A) exercising and 67 in full operation. On natural gas the fuel cost is trivial. On propane it draws down a tank you pay to fill, which is a real argument for setting the exercise cycle to the minimum your manual allows.
The 12-volt starting battery is a consumable, and it is the number one reason a standby unit fails to start when it is finally needed. Generac specifies an AGM Powersport battery with a minimum 310 cold cranking amps for the 72610.
Permits, code and where it can sit
Clearances follow NFPA 37, as commonly enforced:
- 5 feet from any opening in a wall — operable windows, doors, vents, window wells.
- 5 feet from the back of the unit to a combustible wall, or 18 inches based on Southwest Research Institute testing.
- 5 feet of clearance above.
- 3 feet at the front and both ends.
The 18-inch figure is the one installers use, because it lets a unit sit close to the house. But the 5-foot rule from any operable window, door or vent is not waived by it, and that is the constraint that most often forces a longer and more expensive gas and electrical run. It is also the most common cause of a failed inspection.
Two caveats. We cited a municipal summary of NFPA 37, not the standard itself, which is paywalled — and notably, neither Generac’s nor Kohler’s product pages publish clearance figures at all, with Kohler explicitly deferring to the dealer. Pull your specific model’s installation manual before finalising placement. Manufacturer instructions supersede the standard where they are stricter, and your local inspector may be stricter still.
Expect two or three separate permits — electrical, mechanical or gas, and sometimes building or zoning for the pad. A single-permit quote may be incomplete. Inspection is required before the transfer switch is energised.
On noise: 67 dB(A) under load is comparable to a loud window air conditioner, but it is running at 2am on a quiet street. Many municipal ordinances set residential night limits around 50 to 55 dB(A) measured at the property line, which a unit near a boundary can exceed. HOAs commonly regulate placement, screening and exercise timing. Check your municipal code and your CC&Rs before you sign, because relocating a unit afterwards means redoing the pad, the gas line and the conduit.
Does it add home value? Probably not
The claim that a generator adds around 5 per cent to home value appears on dozens of pages. We could not find a study, survey or dataset behind it. On a $500,000 home, 5 per cent would be $25,000 — roughly double the installed cost. That should fail the smell test on its own.
The people with no financial stake in the answer say something different. Practising appraisers report making no dollar adjustment for whole-house generators, at most folding them into an overall quality rating. Their stated reason is that MLS data rarely captures generators, so there is no paired-sales evidence from which to build an adjustment. One appraiser met a claimed “1 to 1.5 times cost” valuation with a blunt request for the evidence behind it.
Note who is on which side of this argument: nearly every page claiming generators add value is published by a company that sells or installs them.
Buy a standby generator because you want power during outages, not as an investment. There may be a marketability effect in specific markets — the post-hurricane Gulf Coast, ice-storm Texas, California under public safety power shutoffs — where it helps a house sell faster or breaks a tie. Even that is anecdotal.
Questions people actually ask
I have natural gas. Is a 22kW generator really 22kW?
No. Generac’s brochure rates the 22kW model 7042 at 19.5kW on natural gas. Depending on model the derate runs from zero to 13.5 per cent. Size up one step, or verify the specific model number on the manufacturer’s page before signing.
What will a week-long outage cost me in fuel?
Using Generac’s published consumption and current EIA fuel prices, a 24kW at half load burns 197 cubic feet an hour on natural gas, about $4.75 an hour or $114 a day; or 2.45 gallons an hour on propane, about $6.54 an hour or $157 a day. A week is roughly $800 on gas and $1,100 on propane.
How big a propane tank do I need?
Tanks fill to 80 per cent, so a 500-gallon tank holds 400 usable gallons — about 6.8 days at half load on a 24kW. A 250-gallon tank gives about 3.4 days. Five hundred gallons is the practical minimum, at roughly $1,500 installed above ground or $2,000 buried.
Can I save money with a portable and an interlock kit?
Yes, substantially: roughly $1,700 to $2,150 all in against $9,600 to $14,300. You give up auto-start entirely, you refuel every 8 to 12 hours during the storm, and you manage load manually at the panel.
Do I get a tax credit?
For the generator, no — it never qualified. For a home battery, no, not any more: the IRS states the credit is not available for any property placed in service after 31 December 2025, and what counts is when installation was completed rather than when you paid.
How far from the house does it have to sit?
Per NFPA 37 as commonly enforced: 5 feet from any operable window, door or vent, 5 feet above, 3 feet at the front and both ends, and 5 feet from a combustible wall, reducible to 18 inches on the basis of Southwest Research Institute testing. The 5-foot rule from openings is usually what dictates placement. Your model’s manual and your local inspector both override this.
How long is the warranty?
Five years, limited, for both Generac and Kohler — verified on their live product pages. Home Depot’s Generac 7326 listing specifies the five years covers the transfer switch as well.
What is the real annual cost of ownership?
Budget $200 to $400 a year for professional service, plus fuel for the weekly exercise cycles, plus a starting battery every few years. Note that Generac’s own support page refuses to publish maintenance intervals and refers you to your model’s manual.
What we could not verify
- A national average installed cost for a genuine 18kW-plus whole-house install. No manufacturer, retailer or government source publishes one. Our $9,600–$14,300 is computed from verified components, not surveyed.
- Tesla, Enphase or FranklinWH pricing from the manufacturers themselves. None publish prices, capacities, power ratings or warranty lengths. All battery figures here are marketplace quote averages.
- The third-party-ownership route for claiming a commercial credit on a residential battery in 2026. Sourced only to a solar marketing site; not confirmed against the IRS.
- State and utility rebates for 2026. These are now the primary incentive and vary enormously. Check yours.
- NFPA 37 itself — paywalled. Clearances came from a municipal summary, and neither manufacturer publishes them.
- Maintenance intervals and full warranty schedules from either manufacturer.
- Residential diesel pricing or any liquid-cooled unit above 28kW.
- Gas meter upgrade cost from a utility or government source.
- The “adds 5% to home value” claim. No study, survey or dataset found anywhere.
- Generac’s 14kW natural gas consumption figure of 189 cubic feet an hour, which is implausibly close to the 24kW’s 197 and is likely a specification error.
We also found one widely-circulated fuel consumption chart publishing propane figures roughly forty times too high — a units error, cubic feet printed under a gallons heading, contradicting itself within the same page. Use the manufacturer’s own product pages for consumption data.
The short version
- Budget $9,600 to $14,300 for a 24kW whole-house install. Averages near $5,000 are below the price of the equipment.
- On natural gas, size up. A “22kW” unit is 19.5kW on gas.
- Ask about gas line capacity before signing, not after the inspection fails.
- You probably do not need to power the whole house. NEC 702.4(A)(2) lets an energy management system do the work instead.
- The federal battery tax credit ended for anything placed in service after 31 December 2025. Generators never qualified.
- A portable plus an interlock costs about $2,000 and is the right answer for many households — as long as you will be home to start it.
- Do not buy it as an investment. Appraisers make no adjustment for generators.