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Backup generator FAQ

Most generator decisions come down to four numbers: about $5,090 for an average whole-house standby install (typical range roughly $1,524-$8,658, Bob Vila 2026), how many minutes of outage you actually face, whether you need whole-home or essential circuits, and the safety rules for portables. Portable generators must sit at least 20 feet from windows, doors and attached garages (Ready.gov). CPSC documented at least 1,332 portable-generator carbon monoxide deaths from 2004 through 2021.

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40 questions answered

The three questions homeowners ask first

Answered in full here so you do not have to hunt. Everything else is grouped below.

How much does a backup generator cost in 2026?

Bob Vila’s 2026 data puts a whole-house standby install around $5,090 nationally, typically about $1,524-$8,658. Units run roughly $2,000-$3,500 at 7.5-10 kW, $4,000-$5,500 at 14-18 kW and $5,000-$6,500 at 20-24 kW; labor adds $1,500-$5,000. Transfer-switch labor is about $1,200; permits often $50-$200 each. See our generator cost guide.

Is a backup generator worth it?

It depends on your outage exposure. EIA data for 2024 show the average U.S. customer lost about 663 minutes of power including major events but only about 132 minutes excluding them - so much of the case is storm insurance. Wells, sump pumps, medical equipment and long rural outages strengthen the case considerably.

How far should a portable generator be from the house?

At least 20 feet from windows, doors and attached garages, and always outdoors, per Ready.gov. A garage with the door open is not outdoors - CPSC testing found compliant units in an open attached garage still produced CO levels high enough to injure people in living spaces.

This page answers the cross-cutting generator questions that do not belong on a single product page - load lists, transfer switches, fuel cost, permits and the CO reality of portables. Where a deeper page already owns the answer, we point there.

Three patterns cause most bad outcomes: buying two size classes larger “just in case,” accepting an install without a proper transfer switch, and running a portable in a garage. The defense is a written load list, three itemized bids, and your utility’s outage history for your address.

Numbers below use 2026 published ranges. Size, fuel, gas-meter capacity and site work still move the number - three itemized bids beat any national average.

This page answers 40 real homeowner questions about backup generators, grouped so you can skip to the stage you are in.

By topic

Cost and pricing

Each answer is self-contained. Where a deeper page exists, the last sentence links to it.

Hard. Bob Vila’s 2026 figures: small 1-6 kW about $500-$1,800, mid-size 14-18 kW $4,000-$5,500, 20-24 kW $5,000-$6,500, and 26-32 kW $6,500-$15,000 for the unit alone. Large whole-house models can run $5,000-$18,000 before labor. Going up a size class “just in case” is a common way to overspend.
Bob Vila puts transfer-switch installation labor around $1,200 for roughly four hours of work, on top of the switch hardware. Concrete pads run about $50-$75 per square foot. Subpanels may add $530-$2,000; a dedicated circuit $500-$1,000. Ask whether pad, permits and gas line are in the headline number.
Bob Vila estimates roughly $90 a day for a 21 kW natural gas unit, about $175 a day for a 20 kW diesel, and about $220 a day for a 20 kW propane unit. Over a week-long outage that is a real number - and a strong argument for natural gas if you have a service line.
About $80-$300 per visit, per Bob Vila. A well-maintained standby unit is generally expected to last at least 20 years. Divide install cost across that lifespan honestly, including service and fuel - not just the purchase price.
Usually different scope: transfer switch type, subpanel, gas piping length, meter upsizing, pad, permits or “whole home” vs essential circuits. Break bids into unit, electrical, fuel line, pad and permits. Two quotes that look far apart are often two different jobs.
Not always. The jump from 14-18 kW ($4,000-$5,500) to 26-32 kW ($6,500-$15,000) is large. Many homes are better served by essential circuits (furnace, well, fridge, sump, a few outlets). Ask for both quotes with covered circuits listed.

Hiring and quotes

Three itemized bids with unit model, kW, transfer switch, covered circuits, gas or propane work, pad, permits and labor separated. Two bids cannot tell you which one is the outlier.
Unit model and kW, automatic transfer switch specification, list of covered circuits, fuel type and piping scope, pad, permits (electrical and gas), utility coordination if the meter must be upsized, timeline, warranty and maintenance plan price if bundled. “Complete installed system” alone is not a quote.
No. It combines gas piping and service-entrance-level electrical work, both permitted and inspected in most places. Bob Vila’s installation guidance is explicit that only a licensed electrician should install the automatic transfer switch. See generator services.
Code and permitting are local, so the exact requirement depends on your jurisdiction. Practically, no reputable installer will connect a standby generator without one - it keeps your generator from backfeeding utility lines and endangering lineworkers. Walk away from anyone who suggests plugging into a dryer outlet to power the house.
The contractor, in their name, for both electrical and gas/plumbing permits in most standby installs. Get which permits, approximate fees ($50-$200 each is a common planning range), and who schedules inspections in writing. “We handle it” is not an answer.
Longer than most people expect because permits and utility gas coordination happen before anyone pours a pad. Ask for the permitting timeline in your city and the unit lead time in writing - those two drive the calendar more than labor hours.

The work itself

Add total running watts of what you want on, then add the single largest motor starting surge. Stay at or below about 90% of rated capacity. Bob Vila’s reference points put 7,500 W at a one-bedroom basics level, 10,000 W at two bedrooms including a water heater, and 25,000 W at fuller coverage of a larger home - starting points, not a substitute for a load list.
Standby costs far more up front (around $5,090 installed average) but starts automatically on piped fuel. Portables cost hundreds to a couple thousand but require you to place them 20 feet out, start them, run cords and refuel - and they dominate CO deaths. Choose based on what you will actually do at 3 a.m. in a storm.
Natural gas is generally much cheaper to run if you have a service line - about $90 a day for a 21 kW unit versus about $220 a day for a comparable propane unit (Bob Vila). Propane needs tank management and deliveries but can perform better in extreme cold. Diesel is another option with its own storage and maintenance burden.
Large generators can outrun an existing meter. Utilities often must upsize it before install. Find out before you sign - not after the pad is poured. That coordination is a common schedule bottleneck.
It isolates your house from the utility grid before the generator energizes anything. Without it, generator power can backfeed utility lines and electrocute crews restoring power. It is the single most important part of a standby install - not a place to cut cost.
List what must run: heat, well or municipal needs, refrigeration, sump, medical equipment, a few lights and outlets. Price that list against full whole-home. Most homes do not need every circuit at once; load management panels can stretch a smaller unit.

Problems and safety

Gasoline left sitting often varnishes the carburetor. Bob Vila’s guidance is to run a portable every two weeks for five to ten minutes if fuel is in the tank, and to use stabilizer for shorter storage rather than leaving untreated fuel. Dead batteries and dirty plugs are the other usual suspects.
Often undersizing or too much on the transfer switch. Sizing math is running watts plus the largest starting surge; central air alone can need roughly 3,000 running watts and about three times that to start. Keep load near or below 90% of rated capacity.
No. CPSC testing found generators meeting current voluntary standards, run in an attached garage with the bay door fully open, still produced carbon monoxide concentrations in living space high enough to injure occupants. Open doors do not make an enclosed space safe.
CPSC’s rulemaking record documents at least 1,332 CO deaths involving portable generators from 2004 through 2021 - about 74 a year on average, with roughly 85 a year across 2017-2019 - plus thousands of non-fatal poisonings. Placement is the main controllable factor. See generator emergency and safety.
No. Treat onboard shutoff as a last-resort backstop, not permission to move the unit closer. CPSC testing showed open-garage operation could still poison living space - sometimes without tripping the unit’s own shutoff as people expect.

After the job, warranty and maintenance

A well-maintained standby unit is generally expected to last at least 20 years, per Bob Vila - assuming oil changes, filters and annual service actually happen. Skipping service is how a good unit fails on the one night you need it.
Plan on oil roughly every 100 hours of operation, air filter and spark plug service at about a year or 100 hours (whichever comes first), and professional service every two years or 200 hours (Bob Vila). Standby units also self-test weekly for several minutes to keep the battery charged. See generator maintenance.
Sometimes. Value is usually battery load testing, transfer-switch inspection and priority service - not just an expensive oil change. At $80-$300 a visit, compare what each visit includes before bundling a multi-year plan into the install pitch.
Unit model matches the quote, transfer switch and circuit list match, permits closed or inspection scheduled, exercise cycle demonstrated, CO alarms in the home, warranty registration, and who to call for service. Keep the load list with the paperwork.
Document the same day, notify in writing, and use liability insurance if they stall. Ask for certificates of insurance before excavation or gas work. Pre-construction photos of the pad site and utility marks help.

Uncomfortable questions worth asking

Often it is a sales walk. Ask for a written load list with running and starting watts, not a square-footage guess. If they will only quote the largest whole-home unit, that tells you what they are optimizing for.
Transfer switch type, gas piping, meter work, pad, permits, warranty length and whether essentials or whole-home is included. Compare line items and covered circuits before you chase a brand badge.
It depends on your contract and state law. Ordered generators and custom pads create sunk costs. Read cancellation and special-order clauses before the unit is ordered - lead times make cancellation expensive.
You are weak once site work starts. Lock kW, model and covered circuits in the signed scope. Change orders need written approval and a price. “While we’re here” whole-home upgrades are how essentials jobs become $15,000 unit quotes.
Price the install without the plan so bids are comparable. Then buy service on its own merits - battery test, transfer-switch inspection, oil and filters - not as a same-day bundle you cannot unpick from the equipment price.
Honest limits

Questions where the honest answer is “it depends”

Jurisdiction, policy and house-specific questions. We give you the procedure for finding out, not a confident national guess.

Do I need a permit for my generator?

For a permanently installed standby generator, usually an electrical permit and a gas permit - commonly $50-$200 each as a planning range - but thresholds and fees are set by your city or county. Call the building department with the scope. More on generator permits.

How many outage minutes does my address actually see?

National EIA averages (about 663 minutes including major events and 132 excluding them in 2024) are not your street. Ask your utility for outage history at your address - many will provide it - before you spend thousands on insurance against a problem you may not have.

Will homeowners insurance give a discount for a standby generator?

Sometimes, sometimes not - it is carrier- and policy-specific. Call your insurer with the equipment details. Do not bake a discount into the purchase math until they confirm it in writing.

What size generator does my house need?

Only a load list of the circuits and appliances you want backed up answers that - running watts plus the largest starting surge, kept near or below 90% of capacity. Square-footage rules and salesperson “whole home” defaults are guesses. Insist on the written load calculation.
How to use this page

Getting a real answer, not a sales answer

A few rules of thumb that apply across almost every question above.

  • Write the load list before you shop Circuits and starting watts first. kW second. Square footage last.
  • Three itemized bids Unit, transfer switch, gas, pad, permits - separated so scopes match.
  • Never skip the transfer switch Backfeeding kills lineworkers. No dryer-outlet “workarounds.”
  • Portables stay 20 feet out Ready.gov clearance. Garages with open doors still kill people.
  • Ask your utility for outage history Beats any national average for deciding whether to spend.
Sources

Where these figures come from

Sources last checked

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Who wrote and checked this

Written by

The HomeMatchup Content Team

Editorial
Reviewed by

Michael Thompson

Senior Home Improvement Reviewer · 20 years

Senior technical reviewer.

Team-written. Second-person reviewed. Sources dated. Report a correction.

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