Backup Generator Installation in Phoenix, AZ
Costs, sizing, fuel, permits and installers
Compare whole-house generator installation costs in Phoenix, estimate the generator size your home needs, and explore natural gas, propane, and standby backup options. Learn about local permits, APS and SRP requirements, and qualified generator installers.
Phoenix generators at a glance
Most Phoenix homes need a generator less than a battery: outages are short on average. But monsoon storms can knock out thousands of customers at a time, and a generator keeps running as long as it has fuel. This guide covers the local outage record, costs, sizing, air conditioning, fuel, permits, utility rules and how to compare installers. Where we could not confirm something we say so.
Sources: Generac, Kohler and Cummins sheets, EIA, APS and SRP, the City of Phoenix, CPSC. Checked October 20, 2026. Full list at the bottom of the page.
Whole-house generator installation cost in Phoenix
We could not find a verified Phoenix installed price. Generac says home standby installations run about $8,000 to $16,000 including the generator itself (manufacturer statement, undated page, not a price list; source); that is a U.S. figure. Equipment list prices we read on the makers’ pages on October 2, 2026 are for the generator alone. The rest is the transfer switch, pad, gas line or propane tank, permits and labor. The federal credit does not apply: a generator never qualified, and the home energy credits ended in 2025.
| Size class | Example models and list price (generator only) | Installed price |
|---|---|---|
| 10 to 14 kW (essential circuits) | Generac 14 kW from $4,569 | Within the U.S. range of $8,000 to $16,000 (Generac); no size-specific figure found |
| 18 to 20 kW | Generac 18 kW from $5,379; Kohler 20RCA from $6,016 | Same range; no size-specific figure found |
| 22 kW | Generac 22 kW from $6,119 ($6,979 with a 200 A switch) | Same range |
| 24 to 26 kW | Generac 24 kW $6,559; Kohler 26RCA from $7,546 | Same range; larger units can sit near the top |
| Essential-circuit backup | Usually the 10 to 14 kW class with a smaller switch or panel | Lower part of the range, depending on the job |
| Whole-house automatic backup | Usually 20 to 26 kW with a service-rated switch | Middle to upper part of the range, depending on the job |
Equipment list prices read from the makers’ pages on October 2, 2026 (U.S. MSRP examples; not offers). Installed prices are the U.S. statement from Generac; we found no verified price by size or for Phoenix.
What the installed price includes
| Part of the job | What it is | Verified price? |
|---|---|---|
| 1. Generator equipment | The unit; list prices above | Yes, list prices (U.S.) |
| 2. Transfer switch | An automatic transfer switch, service-rated for whole-house backup; Generac lists one with a 200 A switch for $860 more on the 22 kW | Partly (one example) |
| 3. Electrical installation | Wire, conduit, breaker, connection to the panel | No; itemize on the bid |
| 4. Fuel piping or propane system | Gas line from the meter, or a tank of at least 250 gallons and its set-up | No; itemize on the bid |
| 5. Pad and site preparation | A concrete or gravel pad; trenching if needed | No |
| 6. Permits and inspections | City electrical, gas and (for propane) Fire permits; we found no published Phoenix fee | No |
| 7. Labor and commissioning | Installation crew, startup test, orientation | No |
| 8. Total installed price | Sum of the above | U.S. range $8,000 to $16,000 (Generac) |
What pushes the price up
- Distance from the generator to the electrical panel and to the gas supply.
- Natural gas availability: a new gas line, or a meter or pipe that cannot carry the load, can be a large part of the bill.
- Propane: a tank of at least 250 gallons, its set-up and a Fire permit.
- Trenching and underground utilities, difficult access or a hard-to-place pad.
- Panel modifications and the transfer-switch rating (service-rated for whole-house).
- Generator capacity, and load-management modules that can let a smaller unit do more.
- Permits and inspections in your city.
A worked example, with the assumptions shown
Say the generator is a Generac 22 kW at its $6,119 list price, and the finished job lands inside Generac’s $8,000 to $16,000 range. Then everything besides the generator (transfer switch, electrical work, gas line, pad, permits and labor) is about $1,881 to $9,881 (our subtraction). A short run with gas already at the pad sits near the low end; a long run, a new gas line or a propane tank sits higher. This is an example, not a quote.
Phoenix generator installation cost estimator
This helps you see where your job may fall in the typical installed range. It is separate from the generator size calculator: that one finds the size; this one looks at cost. Answer a few questions; we show what pushes your job up and what is still unknown until a site visit.
Estimate your installation cost
Free, no sign-up. A rough guide, not a quote.
What size generator do you need in Phoenix?
Choose what you need to run at once. The calculator adds the running watts, then adds the largest motor-starting surge (assuming the biggest motor starts by itself, a simplified assumption you can change in Advanced). In Phoenix, include the air conditioner: its starting current is far larger than its running current. This is a screening tool, not a design.
What size generator do you need?
Free, no sign-up. Pick what must keep running.
Wattages come from published appliance guides (Honda, Champion, Generac, ENERGY STAR); starting watts are often 2 to 3 times running watts. Check your own labels.
Whole-house versus essential-circuit generators
| Whole-house backup | Essential-circuit backup | |
|---|---|---|
| Typical capacity | Usually 20 to 26 kW with a service-rated transfer switch | Usually 10 to 14 kW with a smaller switch or panel |
| What it runs | The whole home, including a central air conditioner | Chosen circuits: fridge, lights, internet, a furnace blower and perhaps one cooling unit |
| Transfer switch | Service-rated automatic switch at the meter or main panel | Smaller automatic switch or a dedicated backup panel |
| Installation complexity | More: larger gas line, service-level switch | Less: smaller unit and circuits |
| Operating cost | Higher fuel use at the same load; sized for the whole house | Lower, because the generator is smaller |
| Air conditioning | Can run the central unit | Usually one unit, with load management or a soft starter |
A smaller, correctly designed system can meet many homeowners' needs without powering every appliance at once. Generac's automatic transfer switch can manage up to four air conditioner loads without extra hardware, and optional Smart Management Modules shed large loads so a smaller unit can cope, which in many cases lowers the size and cost of the system (Generac). Do not buy a larger generator than your loads justify. Automatic systems restore power on their own; manual ones need you to start and switch.
| Standby generator | Portable generator | |
|---|---|---|
| Installation | Permanent pad, gas line, transfer switch; professional install and permits | Roll out and connect through a transfer switch or inlet; never plug into a wall outlet |
| Fuel | Natural gas or propane vapor | Gasoline, propane or dual fuel; refueling during an outage |
| Starts | Automatically (with an automatic transfer switch) | By hand |
| Typical size | 10 to 26 kW for homes | Often 3 to 12 kW |
| Safety | Outdoors only, set per manufacturer and code clearances | CPSC: at least 20 feet from the home, never in a garage; battery CO alarms inside |
CPSC (May 27, 2026) gives the 20-foot rule for portable generators; permanently installed standby units follow the manufacturer's clearances and local code. CPSC.
Can a generator run your air conditioner in Phoenix?
Yes, if it is sized for it. A central air conditioner is the hardest load to start: it draws far more current for an instant when the compressor starts (locked-rotor current) than it does while running. One manufacturer's sheet (Goodman GLXS series, 230 V) lists these compressor currents; locked-rotor current is a brief starting value, not continuous running power.
| Air conditioner | Running current (RLA) | Locked-rotor (starting) current (LRA) | Running VA (our arithmetic) | Starting VA (our arithmetic) | Starting VA with a soft starter* |
|---|---|---|---|---|---|
| 3 ton | 13.4 A | 83.3 A | 3,082 | 19,159 | 4,790 |
| 4 ton | 19.4 A | 127.7 A | 4,462 | 29,371 | 7,343 |
| 5 ton | 23.9 A | 148.0 A | 5,497 | 34,040 | 8,510 |
VA = amps x 230 volts, ignoring power factor; one brand and series only, so other units differ. *A soft-starter maker (Micro-Air) says its EasyStart cuts start-up current by up to 75%; that is a maker claim, not an independent test. Goodman spec sheet (reseller-hosted copy). Read the nameplate on your own outdoor unit.
- Running load: a 3-ton unit runs on about 3,100 VA by this sheet, a 5-ton about 5,500 VA, before anything else in the house.
- Generator motor-starting ability is the real limit, and it rarely sees the full locked-rotor current for long; compare the generator's own motor-starting specification with your air conditioner.
- Soft starters and load-management modules cut the surge or shed other loads while the compressor starts, so a smaller generator can cope.
- Other loads: cooling the house while running a refrigerator, lights and internet adds only a few hundred watts; an electric water heater, dryer or range adds thousands.
- Heat: a generator in 110°F air loses about 9% (Generac rule) to 12% (Kohler rule) of its rating (our arithmetic; chart above).
- Our calculator's simple case uses the actual nameplate-style currents above; use Advanced to add a soft starter or two motors starting together.
Natural gas versus propane standby generators in Phoenix
| Natural gas | Propane | |
|---|---|---|
| Where the fuel comes from | The utility line (Southwest Gas serves Phoenix); no tank or deliveries | A tank on your property, filled by delivery |
| Installation | Needs a gas meter and pipe that can carry the generator's load; a new line adds cost | Needs a tank of at least 250 gallons for a standby unit and its set-up |
| Runtime | As long as the gas supply keeps flowing | About 79 hours at half load on a 250-gallon tank (80% usable), our arithmetic for a Generac 22 kW; a 500-gallon tank roughly twice that |
| Generator output | Typically 10 to 20% below the propane rating (Generac manual) | The full rating |
| Fuel use, Generac 22 kW | About 203 to 228 ft³ an hour at half load; 306 to 327 at full load | 2.53 gallons an hour at half load; 3.90 at full load |
| Permits | Gas permit for new piping | Gas permit plus a Fire Department permit (see Phoenix permits) |
| Considerations | Generac notes that a strained grid supply may reduce available gas during a widespread event | Stored fuel keeps working if the gas main does not |
- Do not assume every Phoenix home has natural gas. Ask Southwest Gas whether service reaches your address and whether the meter and piping can carry the generator's load (the 22 kW Generac uses up to about 327 cubic feet an hour). We could not read Southwest Gas's own generator, fee or capacity pages.
- Propane in Phoenix: a Fire Department construction permit is required for LP-gas containers of 125 gallons or more, and for any R-3 (house or duplex) vapor-service container under 125 gallons (2024 Phoenix Fire Code packet). Tank distances to the house and property line come from model codes that we could not read.
Generator fuel consumption and running cost in Phoenix
Pick a generator, a fuel and a load to see fuel use and cost for 8, 24 and 72 hours. It uses each maker's fuel table; we interpolate between the half-load and full-load points and say so below the result.
Estimate your fuel cost
Free. Maker fuel tables, Arizona gas prices.
Sources: EIA Arizona natural gas, EIA propane, and the makers' spec sheets (links in the equipment table). Propane gallons for Kohler and Cummins are our conversion at 36.39 ft³ per gallon.
Phoenix power outages and backup power needs
In 2024 the average APS customer lost 81 minutes of power on a normal year (87 with major events) and the average SRP customer 53 (58), per EIA Form 861. These are whole-utility averages, not Phoenix-only numbers, and they hide the storm days:
- August 9-10, 2026 (check date): A monsoon storm knocked out power to about 23,000 APS customers at its peak; the next morning about 4,500 APS customers and nearly 3,000 SRP customers were still out, and more than 120 poles were down, mostly from very high winds. (KJZZ)
- August 11, 2026: Another storm cut power to about 1,100 APS customers in north Phoenix and about 2,600 SRP customers in Maryvale and Tolleson; most were restored by about 7:30 to 9 a.m. (azfamily.com)
- See also the August 2025 and July 2026 storms on our battery backup page.
Those are news reports, not utility releases, and the KJZZ article's weekday labels are inconsistent, so treat its date as approximate. We found no official APS or SRP statement of how long each customer was out. Heat makes any outage harder: the normal July high is 106.5°F, and cooling is the load people miss most. An honest note: many Phoenix homes have only brief or infrequent outages, and a generator is not necessary for everyone. Consider it if you have long storm outages, medical needs, or work at home, and compare it with a home battery.
Phoenix generator backup by the numbers
Outages, the air conditioner, fuel cost and Phoenix heat.
Minutes without power in a year
Average customer, 2024, whole-utility numbers (EIA Form 861). Averages hide storm days: a generator is mostly for the long outage, not the typical year.
An air conditioner draws far more starting than running
VA = amps x 230 volts, ignoring power factor, from one maker's sheet (Goodman GLXS). *A soft-starter maker says it cuts start-up current by up to 75% (a maker claim, not an independent test). Read your own nameplate.
Fuel cost per hour, Generac 22 kW
Arizona residential natural gas $17.24 to $26.31 per Mcf (EIA, Jan and Jul 2026); propane $2.668 a gallon is the U.S. average (EIA, March 2026), not a Phoenix delivery quote. Our arithmetic from the maker's sheet.
Generator list prices (equipment only)
Maker list prices read October 2, 2026. The finished job also includes the transfer switch, pad, gas line, permits and labor: Generac says home standby installs run about $8,000 to $16,000 in all (U.S. figure, not a Phoenix quote).
Typical all-in installed range, U.S. (Generac): $8,000 to $16,000.
Heat takes a bite out of the rating
Generac and Cummins: about 3.5% per 1,000 ft and 1% per 10°F above 60°F; Kohler: 4% per 1,000 ft above 500 ft and 2% per 10°F above 60°F. Phoenix sits near 1,100 ft; normal July high 106.5°F, record 122°F. Our arithmetic, on a 22 kW rating.
Sources: EIA Form 861 (2024) and EIA fuel prices; KJZZ and azfamily storm reports; Generac, Kohler and Cummins spec sheets and manuals; Goodman spec sheet; maker list prices (Oct 2, 2026); NWS Phoenix. Checked October 20, 2026.
Automatic transfer switches and APS and SRP requirements
An automatic transfer switch senses the outage, starts the generator and moves your loads to it, then moves them back when the utility returns. A manual switch makes you do it. In both, the switch must never connect the generator to the grid, so power cannot flow back out to the neighborhood (backfeed), a potentially fatal hazard for line workers. Whole-house systems use a service-rated switch; selected-circuit systems use a smaller one. Install only listed equipment, with a licensed electrician.
APS standby generator requirements
- A standby generator must connect through a double-throw, break-before-make (open-transition) transfer switch listed to UL 1008, designed to never connect the generator to the APS system, even during testing.
- You must give APS the manufacturer's open-transition documentation and a one-line diagram, and post a permanent warning placard at the service entrance (APS Electric Service Requirements Manual, section 104.11-1, revised May 15, 2026). APS manual.
SRP standby generator requirements
- A standby system must transfer load in open-transition mode with a UL 98 safety switch, a UL 1008 transfer switch or a trapped-key interlock, and SRP will verify the transfer scheme. SRP interconnection handbook.
- SRP's separate stand-by generator document and any registration steps or fees we could not find; ask SRP.
- Closed-transition or inverter schemes that run alongside the grid are treated as interconnected generation and need the utility's approval; they are not the same as a permanently isolated standby system.
- Inspection: the switch must be inspected and approved by the city or county electrical agency.
- Never connect a generator to a dryer or wall outlet.
Phoenix generator permits, codes and installation process
- Electrical permit: the City of Phoenix says any work that connects power to premises wiring needs a permit, and the permit scope includes any separately derived source of power such as a generator. A permanently wired standby unit with a transfer switch is not exempt. (City interpretation, revision 8/13.) City document.
- Gas permit: new gas piping for natural gas or propane needs a permit; the City's over-the-counter list covers exterior gas appliances from a natural gas meter, and all propane installations go through plan review (2017 guideline). Over-the-counter guideline.
- Fire permit for propane: required for LP-gas containers of 125 gallons or more, and for any one- or two-family-home vapor-service container (2024 Phoenix Fire Code packet, effective February 17, 2026). Fire Code packet.
- How to apply: the City uses the SHAPE PHX portal (Release 3 effective April 27, 2026). Planning and Development: 602-262-7811; Fire Prevention: 602-262-6771. SHAPE PHX.
- Codes: the 2024 Phoenix Building Construction Code, which adopts the 2023 National Electrical Code (Phoenix has no amendment to the optional-standby article) and the 2024 International Fire, Building, Residential and Fuel Gas Codes with Phoenix amendments, effective August 1, 2025 (City code page, checked October 20, 2026).
- Licensing: use a contractor licensed in Arizona; we could not read the Registrar of Contractors' classification pages to say which license covers generator work, so ask the installer and check the license on the ROC lookup.
- Not confirmed: permit fees, the zoning setback to property lines, and whether the City's older (2013 to 2017) documents have been replaced. Ask your installer and confirm with Planning and Development.
- Unincorporated Maricopa County and other cities (Scottsdale, Tempe, Mesa, Glendale, Chandler and others) have separate offices and rules; a Phoenix mailing address does not mean the City of Phoenix issues your permits. HOAs: we read the Arizona statutes for planned communities and condominiums and found no provision on generators; your community documents may still restrict them.
The installation process
- Initial site assessment by the installer.
- Home load calculation (what the generator must run, including the air conditioner's starting current).
- Generator and fuel selection.
- Placement planning: clearances, gas route, access.
- Written, itemized estimate.
- Permit applications (electrical, gas, and Fire for propane).
- Pad and site preparation.
- Electrical and fuel connections.
- Transfer switch installation and the utility paperwork.
- Inspection and commissioning (startup and a test with the power off).
- Homeowner orientation and a maintenance plan.
Ask your installer for its own timeline; permits, gas work and equipment availability can take longer than the on-site work, and we do not quote a universal duration.
Generator placement, noise and Phoenix heat
Generators run on fuel and make carbon monoxide, so they go outdoors. Two different rules apply. A portable generator must be at least 20 feet from the home with its exhaust pointed away, never in a garage, basement, shed or enclosed patio (CPSC). A permanently installed standby unit follows the manufacturer's own clearances and local code, which take precedence; do not apply one number to every product.
- Manufacturer clearances: Generac says to keep units 5 feet from openings in the wall (operable windows, doors, vents), 5 feet above and 3 feet at the front and ends, and that units with an SwRI label may be as close as 18 inches to a wall at the back; Kohler and Cummins say 18 inches to combustibles. Keep the unit away from fresh-air intakes and point the exhaust away from the home.
- Zoning and property lines: we could not retrieve Phoenix zoning setbacks for generators; ask the City. HOAs may add rules.
- Noise: the Generac 22 kW is rated 67 dBA at 23 feet in normal operation and 57 dBA in quiet-test exercise mode. Phoenix's Good Neighbor guide asks residents to keep noise down between 11 p.m. and 7 a.m.; we found no generator-specific noise limit or testing-hours rule.
- Heat: makers derate about 1 to 2 percent per 10°F above 60°F plus a few percent for altitude, so roughly 9 to 12 percent at 110°F by our arithmetic. Generac tests units to 122°F and recommends an oil and filter change every year or 100 hours when the ambient temperature is above 85°F for continuous operation. A sun-baked pad can be hotter than the air.
- Dust, monsoon and water: keep shrubs at least 3 feet from the louvers, keep the area clear of dust and debris, and keep the pad above standing water; allow service access.
- Carbon monoxide: install working CO alarms on every level; Phoenix requires CO alarms powered from the building wiring with battery backup in new work. Never run a fuel-burning generator in a garage or enclosed space.
Sources: Generac clearance article (March 16, 2026), the sheets in the equipment table, the City of Phoenix 2024 IRC amendments and CPSC.
Generator brands and equipment comparison
A neutral look at what the makers publish. SolutionEnergy is not an authorized dealer or certified partner of any brand, and we do not rank them. The installation matters more than the badge on the unit: size, fuel supply, transfer switch and a licensed installer decide how it performs. Official dealer locators exist for Generac and Kohler (now Rehlko); these are manufacturer tools, not our recommendations.
| Generator | Rating (propane / natural gas) | Natural gas ft³/hr, half | full load | Propane gal/hr, half | full load | Sound (dBA), as the maker tests it | Warranty | List price (Oct 2, 2026) |
|---|---|---|---|---|---|---|
| Generac Guardian 14 kW | 14 kW LP and NG | 195 | 256 | 1.81 | 3.07 | 65 at 23 ft | 5 years or 2,000 hours | From $4,569 |
| Generac Guardian 22 kW | 22 kW LP / 19.5 kW NG | 203 to 228 | 306 to 327 | 2.53 | 3.9 | 67 at 23 ft (57 in quiet-test mode) | 5 years or 2,000 hours | From $6,119 ($6,979 with a 200 A switch) |
| Kohler 20RCA | 20 kW LP / 18 kW NG | 161 | 281 | 2.25 | 3.74 | 70 normal, 66 exercise, at 23 ft | Premium 5-year / 2,000-hour (per the 26RCA sheet) | From $6,016 |
| Kohler 26RCA | 26 kW LP / 24 kW NG | 180 | 290 | 2.34 | 3.54 | 67 normal, 56 exercise | 5 years / 2,000 hours | From $7,546 |
| Cummins QuietConnect RS20A | about 20 kW LP / 18 kW NG (rated in amps) | 172 | 268 | 1.81 | 3.08 | 65 at 23 ft | 5 years / 2,000 hours | Not found |
Read from each maker's sheet on October 20, 2026; not endorsements. Sound figures use different distances and modes (normal run versus quiet-test exercise), so do not rank them directly. Maintenance: Generac publishes oil and filter intervals in its owner's manual (see maintenance below); we did not verify Kohler or Cummins service schedules, so follow their manuals. Local dealer and service availability: we did not verify dealers by city. Briggs and Stratton and other makers: we did not research their current residential standby models, so they are not compared here. We read current Kohler RCA models rather than the older RESAL and RESCL models. Price and availability change.
- Transfer switch compatibility: each maker sells matching automatic transfer switches (for example Generac's switch can manage up to four air conditioner loads without extra hardware). Ask your installer which switch is specified and whether it is service-rated.
- Warranty: the Generac, Kohler and Cummins sheets we read list 5 years or 2,000 hours; Generac says only its authorized dealers can do warranty work.
Generator maintenance, reliability and ownership costs
Installation is not the full cost of ownership. A standby generator needs regular exercise and service, and uses fuel when it runs. Schedules differ by brand, so follow your own manual; the details below are the ones we could verify.
- Exercise cycles: Generac units run for 5 minutes every other week by default (weekly or monthly selectable); Kohler runs a 90-second unloaded exercise by default. The exercise run uses a little fuel and makes noise for a few minutes.
- Oil and filter: Generac says change the oil and filter after the first 25 hours, then every 2 years or 200 hours; in continuous hot weather above 85°F, every year or 100 hours of operation (owner's manual). In Phoenix, plan on the shorter, hot-weather interval after a long run.
- Battery, air filter and fuel system: the starter battery, air filter, spark plugs and fuel connections are covered in each maker's manual; we did not verify replacement intervals or prices, so ask your installer for the schedule and a written price.
- Cooling and airflow: keep shrubs and grass at least 3 feet from the louvers and keep dust and debris clear, especially after monsoon storms; inspect louvers, fuel and oil leaks, and water intrusion each year.
- Long outages: Generac says to stop and inspect a unit after 24 hours of continuous running; watch the unit during long runs.
- Warranty and authorized service: the Generac, Kohler and Cummins sheets we read list 5 years or 2,000 hours; Generac says only its authorized dealers can do warranty work. Ask who services the unit and whether they offer an annual maintenance plan.
- Ongoing cost: fuel when it runs (see the running-cost calculator), service visits and parts. We found no verified Phoenix service-plan prices, so we do not quote one.
Compare generator installers in Phoenix
We do not rank or rate companies. A generator is an electrical, gas and fire-safety job, so compare scope and qualifications, not only the lowest price. Use this checklist on every bid:
| Compare | What to look for | Why it matters |
|---|---|---|
| Arizona contractor license | A license number you can check on the Registrar of Contractors lookup; we could not read the ROC classification pages to say which license covers generator work, so ask which license applies | Unlicensed work risks safety, permits and insurance. |
| Electrical and gas piping qualifications | Who does the wiring and who does the gas piping, and their licenses | Both are regulated work needing permits and inspection. |
| Insurance | Proof of liability insurance | Protects your home. |
| Generator experience | Recent standby installs and your brand; any manufacturer training or authorization is a claim to verify with the maker | We do not verify dealer claims. |
| Load calculation | A written load calculation and an air-conditioner starting-load assessment (nameplate, soft start or load management) | This sizes the system and the cost. |
| Fuel and site | A fuel supply evaluation (gas meter and pipe capacity, or propane tank) and a placement assessment with clearances | Gas capacity and clearances can change the price. |
| Permits | Who pulls the electrical, gas and Fire permits | Permits protect you when you sell or insure. |
| Itemized estimate | Generator model and kW, transfer switch type and rating (UL 1008; service-rated for whole-house), pad, gas line and meter work, propane tank and permit, labor, and the startup test | Totals alone hide differences. |
| Utility paperwork | The transfer-switch documents and one-line diagram APS asks for, or SRP's verification | Required before you operate. |
| Warranty, service and maintenance | Who services the generator, whether they are an authorized dealer, and whether they offer maintenance | Warranty work can depend on it. |
| Inspection and commissioning | City inspection, a startup test and a test with the utility power off, and homeowner orientation | Confirms it works when you need it. |
What a professional quote should show
- The generator model, kW rating on each fuel, and the transfer switch type and rating.
- Fuel plan: gas line route and meter work, or propane tank size, set-up and permit.
- Electrical scope: wire, conduit, breaker, any panel work, and load-management modules if used.
- Pad, trenching and site work; permits and inspections; startup and commissioning; warranty terms and the maintenance plan.
- What is excluded, and what happens if the gas utility or the City needs changes.
SolutionEnergy is an independent information and installer-referral platform, not the company that installs the generator. We are lining up independent, licensed installers in the Phoenix area, including generator installers. Send a request and we will reply ourselves; nothing is shared with an installer unless you choose one, and we cannot promise how many companies will respond. Read how it works.
Commercial generator installation
This page is about home generators. Small businesses, retail and office buildings, restaurants and commercial refrigeration have different needs: business continuity, larger loads, automatic transfer equipment sized to the building, fuel capacity for longer runs, and commercial permits and codes. Commercial projects follow different design and code requirements than a house, so start with a load study from a licensed commercial contractor. Use the quote form below to describe a business project, and see our generator installation guide.
Generator versus battery backup in Phoenix
They store and deliver power differently. A generator is rated in kW, the power it can deliver at once, and runs as long as it has fuel. A battery is rated in kWh, the energy it stores, plus a kW rating for how fast it can deliver it; when the stored energy is gone it stops until recharged. So compare runtime and power together, not cost per kW alone.
| Standby generator | Home battery | Solar plus battery | Portable power station | |
|---|---|---|---|---|
| Installed cost | $8,000 to $16,000 including the generator (Generac, U.S.) | About $10,496 for 13 kWh in Phoenix (EnergySage); Powerwall 3 typically $13,473 installed (EnergySage, U.S.) | Panels and battery together; see our solar page | Hundreds to a few thousand dollars; no installation |
| Usable backup capacity | As much as the fuel supply holds | Fixed: for example 13.5 kWh | Battery size; solar can recharge it by day | Small, fixed |
| Continuous and surge power | 10 to 26 kW; motor-starting varies by model | Powerwall 3: 11.5 kW continuous, 185 A motor start (maker) | Same as the battery and inverter | Low; for small loads |
| Runtime | About 79 hours at half load on a 250-gallon propane tank (our arithmetic, Generac 22 kW) | One 13.5 kWh battery runs a 1.5 kW load about 9 hours; a 3-ton air conditioner at about 3.1 kVA would drain it in roughly 4 hours if it ran nonstop (our arithmetic, ignoring cycling and losses) | Longer in sunny weather if the system is backup-capable | Hours for small loads |
| Automatic operation | Yes, with an automatic transfer switch, after a short delay | Yes, often instant for chosen circuits | Yes, if the equipment is built for backup | Manual |
| Noise and fuel | 67 dBA at 23 ft (Generac 22 kW); natural gas or propane | Under 50 dBA at 1 m (Powerwall 3); no fuel | Quiet; no fuel | Quiet; no fuel |
| Maintenance | Exercise cycles, oil changes, service | Little; software updates | Little | Little |
| Heat | Loses about 1% per 10°F above 60°F; operates to 122°F | Operates to 122°F; may de-rate above 104°F | Same | Check the maker |
| Multi-day outages | Best if fuel lasts | Needs solar or a recharge; sized for essentials | Good if sunny | Not suited |
- Solar does not automatically keep the lights on: a standard grid-tied solar system shuts down in an outage. You need backup-capable equipment (a battery and the right inverter) to use solar power when the grid is down.
- Hybrid arrangements: some homes pair a battery for everyday short outages with a generator for rare multi-day ones.
- Which fits? A battery is quiet, automatic and pairs with solar; a generator suits long storm outages and big cooling loads. Many homes choose by how long their outages run.
See our Phoenix home battery installation guide, Phoenix solar panel installation guide and the backup power comparison guide.
Phoenix generator installation FAQs
How much does it cost to install a whole-house generator in Phoenix?
We could not find a verified Phoenix price. Generac says home standby installs average $8,000 to $16,000 including the generator (a U.S. figure); equipment starts around $6,000 to $7,500 for a 22 to 26 kW unit (maker list prices, October 2026). See the cost section.
What size generator do I need for my Phoenix home?
It depends on what you want to run, mostly the air conditioner. Add the running watts, then allow for the largest motor starting. Use the sizing calculator, then have a licensed installer confirm.
Can a 22 kW generator power my entire house?
Often it can run a whole house if loads are managed, but not always everything at once. A 22 kW unit on natural gas is rated about 19.5 kW, and heat cuts output about 9%, so a house with several large 240 V loads may need load management or a larger unit. A load calculation decides.
Can a generator run central air conditioning in Phoenix?
Yes if it is sized for it. A 3-ton unit draws about 3,100 VA running but up to about 19,000 VA at the instant of start on one brand's data, so size from the nameplate and consider a soft starter or load-management module. See AC backup.
Do I need a permit to install a generator in Phoenix?
Yes. The City of Phoenix requires an electrical permit for a generator connected to premises wiring, a gas permit for new gas piping, and a Fire Department permit for propane containers in a house. Your installer normally handles them. Other cities and unincorporated Maricopa County have their own rules. See permits.
Does APS allow home standby generators?
Yes, with an open-transition (break-before-make) UL 1008 transfer switch that can never connect the generator to the grid, the maker's documentation and a one-line diagram, and a warning placard at the service entrance (APS Electric Service Requirements Manual).
What are SRP's standby generator requirements?
SRP says a standby system must transfer load in open-transition mode with a UL 98 safety switch, a UL 1008 transfer switch or a trapped-key interlock, and SRP will verify the transfer scheme. We could not find SRP's separate stand-by generator document, so ask SRP.
Is natural gas or propane better for a home generator?
Natural gas needs no tank but depends on your gas meter and line capacity; propane needs a tank of at least 250 gallons for a standby unit and a Fire Department permit in Phoenix. Natural-gas output is usually 10 to 20 percent lower. See natural gas versus propane.
How much does a standby generator cost to operate?
Our estimate for a Generac 22 kW at half load is about $3.93 to $6.00 an hour on natural gas and $6.75 on propane; use the running-cost calculator. These are fuel charges only, and propane is a U.S. average, not a Phoenix delivery price.
How long can a generator run during an outage?
As long as it has fuel and is maintained. On a 250-gallon propane tank (80% usable), a Generac 22 kW runs about 79 hours at half load or 51 hours at full load (our arithmetic). Natural gas runs while the gas supply continues; Generac says to inspect a unit after 24 hours of continuous running.
How much does Generac installation cost in Phoenix?
We found no verified Phoenix price. Generac says home standby installs average $8,000 to $16,000 including the generator (U.S.). SolutionEnergy is not a Generac dealer; use Generac's dealer locator to find authorized dealers.
Do whole-house generators require a transfer switch?
Yes. A transfer switch (automatic or manual) is required so power cannot flow back to the grid. Whole-house systems use a service-rated switch. See transfer switches.
How close can a standby generator be installed to a house?
It depends on the make and model and local code. Generac says 5 feet from openings and as close as 18 inches to a wall for units with an SwRI label; Kohler and Cummins say 18 inches to combustibles. The portable-generator rule (20 feet) does not apply to permanently installed standby units. See placement.
Do generators work efficiently in extreme Phoenix heat?
Yes, with some loss: makers derate about 1 to 2 percent per 10°F above 60°F plus a few percent for altitude, so roughly 9 to 12 percent at 110°F by our arithmetic. Units are tested to 122°F.
Is a generator or home battery a better backup option?
A battery is silent and automatic and pairs with solar; a generator runs as long as it has fuel and suits multi-day storms and big cooling loads. See generator versus battery and our Phoenix home battery guide.
Ready to install a home generator in Phoenix?
Find out which standby generator system fits your home, cooling needs, and budget. Compare installation options and request information from independent generator installers serving Phoenix. We read every request and reply ourselves; nothing is shared with an installer unless you choose one, and we cannot promise how many companies will respond. If you used the calculators, your numbers are added to the message for you.
More Phoenix energy guides
- Phoenix, AZ energy guide
- Phoenix solar panel installation
- Phoenix home battery installation
- Phoenix home EV charger installation
- Phoenix metro area guide
- Arizona energy guide
- Generator installation guide
- Generator cost guide
- Generator sizing calculator
- Generators
- Backup power
Sources and data checks
Every number comes from the sources below. Not confirmed: Southwest Gas generator, fee and capacity rules; Phoenix permit fees and zoning setbacks; propane tank distances; SRP's stand-by generator document and any registration steps; an Arizona or Phoenix installed price; the Arizona contractor license classes; and the current wording of the City's older permit documents. Tell us if something is out of date.
| What | Applies to | Source | Checked | Status |
|---|---|---|---|---|
| Reliability | APS, SRP (whole utility, 2024) | EIA Form 861 | October 20, 2026 | Verified |
| Outage events | Phoenix Valley, 2026 | KJZZ, azfamily (news) | October 20, 2026 | Verified (news; date approximate) |
| APS generator rules | APS | APS Electric Service Requirements Manual | October 20, 2026 | Verified (rev 05/15/2026) |
| SRP generator rules | SRP | SRP Distributed Generation Handbook | October 20, 2026 | Verified |
| Phoenix generator permits | City of Phoenix | City electrical interpretation; PDD guideline | October 20, 2026 | Verified (documents dated 2013 to 2017) |
| Phoenix adopted codes | City of Phoenix | Phoenix building code page | October 20, 2026 | Verified (2023 NEC; codes effective Aug 1, 2025) |
| Phoenix propane permit | City of Phoenix | 2024 Phoenix Fire Code packet | October 20, 2026 | Verified (effective 2/17/2026) |
| Equipment specifications | U.S. products | Generac, Kohler, Cummins sheets | October 20, 2026 | Verified |
| Maintenance and derating | U.S. products | Generac owner's manual | October 20, 2026 | Verified |
| Installed cost | U.S. | Generac | October 20, 2026 | Verified (manufacturer statement) |
| Equipment list prices | U.S. | Maker pages | October 2, 2026 | Verified (list prices) |
| Fuel prices | Arizona gas; U.S. propane | EIA | October 20, 2026 | Verified |
| AC starting current | U.S. (one brand) | Goodman spec sheet | October 20, 2026 | Verified (maker sheet) |
| Appliance wattages | U.S. | Honda, Champion, Generac guides; ENERGY STAR | October 20, 2026 | Verified (typical values) |
| Generator CO safety | U.S. | CPSC | October 20, 2026 | Verified |
| Heat and climate | Phoenix | NWS Phoenix | October 20, 2026 | Verified |
General information, not financial, legal or electrical advice. Estimates are ours and are not promises. Use a licensed electrician or installer for all wiring and gas work, and install carbon monoxide alarms; see our editorial policy.