A Generac generator raises the same handful of questions for almost every owner and buyer: how does it work, how loud is it, what does it burn, how long can it run and what do I do when a light comes on? Generac answers most of them somewhere on its website. The trouble is that the answers are spread across product pages, two FAQ sections and dozens of support articles.
This guide puts them in one place. We collected thirty of the most common questions and answered each in plain English, using Generac’s own published guidance. Where Generac states something as a company claim, we say so. Where the answer depends on your model, we tell you where to look.
The questions are grouped: the basics, home standby generators, portable generators, lights and alarms, and buying and service. Jump to the part you need. We have not tested these generators, and nothing here replaces your owner’s manual.
Generac generator answers at a glance
Thirty questions, answered from Generac’s own pages
Figures come from Generac’s FAQ pages, support articles and product pages, checked October 2026.
Quick answer
A Generac home standby generator sits outside like an air conditioner, runs on natural gas or propane and starts by itself within seconds of an outage. Generac says it averages 65 to 67 decibels and should have its oil checked for every 24 hours of use. A Generac portable generator runs on 87 octane gasoline, needs its first oil change after 20 to 30 hours and then every 100 hours, and must only be run outdoors. A green light means ready, yellow means a warning and red means an alarm.
How we put this guide together
We have not tested Generac generators. The answers come from Generac’s home standby FAQ, its portable generator FAQ, its support articles on status lights, error codes and troubleshooting, and its product pages, all read in October 2026. Company history details that are not on Generac’s site are attributed where they appear. Models differ, and Generac updates its guidance, so treat your owner’s manual as the final word.
In this guide
- The Basics
- Home Standby Generator Questions
- Lights, Codes and Alarms
- Portable Generator Questions
- Buying and Service
- Standby or Portable: A Quick Comparison
- Parts That Answer the Most Common Problems
- Common Mistakes Generac Owners Make (and the Fix)
- Pro Tips From Generac’s Guidance
- Real-Life Scenarios: What Would You Do?
- Generac Generator: Quick FAQ
- Your Generac Owner’s Checklist
The Basics
1. What is a Generac generator?
Generac is an American maker of generators. Its range covers portable generators you wheel out and start by hand, home standby generators that are installed permanently and start automatically, and large commercial and industrial units. Generac describes itself as the number one manufacturer of home backup generators. That is the company’s own claim.
2. Who makes Generac generators, and where?
Generac Power Systems makes them. The company says it was founded in 1959, and its headquarters are in Waukesha, Wisconsin. Its home standby FAQ says the standby generators are assembled in Wisconsin, using both foreign and domestic parts.
For portables, the answer depends on the engine. Generac’s portable FAQ says its G-Force and OHVI engines are designed and manufactured in Wisconsin. It also says plainly that Generac OHV engines are not engineered or manufactured in the United States.
3. What types of Generac generator are there?
| Type | Size range | Fuel | Starts | Best for |
|---|---|---|---|---|
| Inverter portable | 2,200 to 3,900 running watts | Gasoline, some also propane | By hand or button | Camping, RVs, a refrigerator |
| Open-frame portable | 3,600 to 18,000 running watts | Gasoline, some dual or tri fuel | By hand or button | Home essentials, job sites |
| Diesel portable | 5,000 running watts | Diesel | Electric | Long hours on farms and sites |
| Air-cooled home standby | 10 to 28 kW | Natural gas or propane | Automatically | Most homes |
| Liquid-cooled standby | 22 to 150 kW | Natural gas, propane or diesel | Automatically | Large homes and businesses |
4. How do I contact Generac?
Generac lists a customer line for the United States and Canada at 1-888-GENERAC, which is 1-888-436-3722. Its website also has guided support, product registration, manuals, a parts lookup and a dealer locator. For a standby generator, there is a service request form that needs your serial number.
5. Where is the model and serial number?
It is on a data label on the generator itself. On a standby unit it is usually inside the enclosure, near the control panel. On a portable it is usually on the frame or the housing. Your manual shows the exact place. Photograph the label. Every parts order, warranty question and service request starts with the model and serial number.
Home Standby Generator Questions
6. How does a Generac home standby generator work?
It is connected to your home’s electrical system through an automatic transfer switch, and to your natural gas line or propane tank. Generac’s FAQ says that within seconds of sensing an outage, the generator starts automatically. When utility power returns, it shuts itself off. It works whether you are home or away.
7. How loud is a Generac standby generator?
Generac’s FAQ says its home standby generators average between 65 and 67 decibels, depending on the model. It compares that to a central air conditioning unit.
8. What fuel does it use?
Natural gas or liquid propane. Generac says each unit is designed to run on one fuel source, which is set when it is installed. It does not need refueling by hand, because it draws from the house supply.
9. How long can a Generac standby generator run?
Generac’s answer is that it will run as long as fuel is available and the unit is maintained. There are two conditions to remember.
First, Generac says the oil level should be checked for every 24 hours of use. A Generac support article goes further for long outages: the unit should be shut down every 24 hours for 30 minutes, to let it cool so the oil can be checked.
Second, on propane, the tank sets the limit. Generac warns that when the propane level falls below about 30%, fuel pressure can be affected and the generator may not start.
10. What size standby generator do I need?
Generac says an authorized dealer can best determine the size, and that a free quote includes sizing options. As a general guide from its website, smaller homes may need 10 to 18 kW, and larger homes with more than one air conditioner may need 22 to 28 kW. Our Generator Size Calculator gives you a starting figure.
11. Can I use a standby generator as my main power source?
No. Generac’s FAQ says its home standby generators are designed as a backup to utility power only and should not be used as a primary power source.
12. Is a Generac standby generator legal in California?
Generac’s FAQ says its home standby generators are considered CARB compliant and can be installed in areas with strict emissions requirements. Local permits and rules still apply, so check with your building department.
13. What affects the cost of installation?
Generac names four things: the fuel type, the intended site, permits and gas meter upgrades. A generator far from the gas meter and the electrical panel costs more to connect than one beside them. We do not quote prices, because they change by region and by job. Generac offers a free quote through its dealers and says financing is available.
14. What warranty does a standby generator have?
Generac’s current listings state that every Generac standby generator comes with a 5-year limited warranty and round-the-clock customer support. Read the warranty statement for your own model, and register the generator after installation.
15. What is Mobile Link?
Mobile Link is Generac’s remote monitoring system. According to Generac, it can send status alerts by text, email or app notification, show run time and the exercise schedule, and let you send a service request to your chosen dealer. Current models have cellular connectivity built in. Some features need a paid subscription.
16. How often does a standby generator need service?
Generac’s maintenance kits are labeled for service every 200 hours or 2 years. The controller shows maintenance reminders as a yellow light. In heavy use, the oil level needs checking every 24 hours of running. Your owner’s manual has the full schedule, and Generac says an owner can do the maintenance if comfortable, or use a service dealer.
17. What battery does it use?
That depends on the generation. Generac’s product pages for its current air-cooled models list an AGM battery of group size BTX20L with at least 310 cold cranking amps, and note that it is not included. Older Guardian models use a different battery, so check your manual.
Lights, Codes and Alarms
18. What do the lights on a Generac standby generator mean?
The lights are visible through a lens on the side of the unit.
| Light | Steady | Flashing |
|---|---|---|
| Green | Ready. Utility power is present and the unit is in AUTO | The generator is running in an outage, or is about to start |
| Yellow | The unit is running in MANUAL, on newer models | A warning is active or maintenance is due. It should still run in an outage |
| Red | The generator is switched OFF | An alarm. A fault has been detected and service may be needed |
| Blue, newer models only | The control panel is in service mode | Not applicable |
Red and yellow together can look orange. For the detail behind a light, look at the control panel, the Mobile Link app or the Mobile Link website.
19. What is the difference between a warning and an alarm?
A warning is a yellow light. Generac says many yellow light codes can be dealt with by the owner, and the generator should still run. An alarm is a red light. It stops the generator from running until it is cleared, and Generac says alarms often need an authorized service dealer if the code comes back.
20. How do I clear a Generac alarm?
Fix the cause first. Generac warns that clearing an alarm again and again without correcting the cause can lead to damage.
- Next Generation models, with the Power Zone 200 controller: hold OFF for at least three seconds. The red light turns steady when the alarm is cleared. Then press AUTO.
- Guardian models, with an Evolution or Sync controller: press the red OFF button, then ENTER, then the green AUTO button.
If the alarm returns, contact a Generac authorized service dealer.
21. What are the most common Generac error codes?
| Code | Name | What it usually means | First step |
|---|---|---|---|
| 1100 to 1101 | Overcrank | The engine turned over but did not start | Check that the fuel shutoff valve is on and the propane tank is not low |
| 1300 | Low oil pressure | The oil level is low | Let it cool for 30 minutes, then check and top up the oil |
| 2100 to 2103 | Overload, remove load | The house is asking for more than the generator can give | Switch off non-essential loads |
| 2750 | Low battery | Battery voltage is low | Give the battery 24 hours to charge. Replace it if that does not help |
| 2800 | Auxiliary shutdown | The emergency shutdown switch is off | Check the switch on the unit |
Generac adds a useful tip. A number followed by (H) on the display, such as 45091 (H), is not an error code. It is the hours of protection.
Our guide to Generac generator troubleshooting covers the codes and fixes in detail.
Portable Generator Questions
22. What fuel does a Generac portable generator use?
Generac’s portable FAQ says to use clean, fresh unleaded gasoline with a minimum of 87 octane. Dual fuel models can also run on propane, and the tri fuel model adds natural gas.
23. What oil should I use, and when do I change it?
| Temperature | Oil |
|---|---|
| Above 32°F | SAE 30 |
| Below 40°F, down to minus 10°F | 10W-30 |
| All temperatures | Synthetic 5W-30 |
Generac says to change the oil after the first 20 to 30 hours of use, and every 100 hours after that. Some current listings give 20 hours for the first change and add “or annually” to the 100-hour interval.
24. How should I store a Generac portable generator?
Generac’s FAQ says fuel begins to deteriorate within about one month. For storage of more than 30 days, it says to drain the fuel from the tank and run the carburetor dry. If you prefer to keep fuel in it, add stabilizer from the start and follow the ratio on the bottle.
Stale fuel is the classic cause of a generator that will not start. Generac describes the result: the engine runs rough or not at all, and the cure is to drain the fuel and clean the carburetor. Our guide to how to store a generator has the full routine.
25. Does a portable generator need to be grounded?
Generac’s FAQ gives a two-part answer. If you use extension cords alone, a ground rod is not needed on its bonded-neutral portables. If you connect the generator to an electrical panel, a manual transfer switch or an RV, it should be connected to a ground rod driven at least 8 feet into the earth. Follow your manual and all federal, state and local rules.
26. Can I run a Generac portable generator in the rain or indoors?
Never indoors. Generac says never to run a portable generator inside a home, a garage or any enclosed area, and to keep it away from doors and windows. It also says never to run one directly in rain, snow or wet conditions, and to protect it from moisture.
Carbon monoxide kills quickly
Generator exhaust contains carbon monoxide, which has no smell and no color. Run a portable generator outdoors only, far from doors, windows and vents, with the exhaust pointing away. Safety agencies advise at least 20 feet. Generac’s COsense feature shuts the engine off if carbon monoxide builds up, but it is a backup, not permission to run a generator in a garage or on a porch. Fit battery-powered carbon monoxide alarms inside your home.
27. What is COsense?
COsense is the carbon monoxide monitor on many Generac portables. Generac’s troubleshooting guide explains its lights. A blinking red light means the engine shut down because carbon monoxide was building up, and the generator must be moved to an open area far from windows, doors and vents. A blinking yellow light means the shutoff was caused by a system fault. If that continues, contact a service dealer.
28. Why will my Generac portable generator not start?
Generac’s quick reference lists these causes, roughly in the order to check them.
- The fuel shutoff valve is off. Turn it on.
- It is out of fuel, or the fuel is stale. Fill it, or drain it and add fresh fuel.
- The oil level is low. A low-oil switch stops the engine. Top it up, and make sure the generator is on level ground.
- The choke is in the wrong position. Too much choke floods the engine.
- The spark plug wire is off, or the plug is bad.
- The air filter is dirty.
- The carburetor is clogged. This usually follows stale fuel.
Generac’s support pages add a simple test. A wet spark plug points to flooding. A dry plug means fuel is not reaching the engine. Our generator won’t start checklist goes through each step.
Buying and Service
29. Where can I buy a Generac generator, and who installs it?
Portables are sold by home centers, online retailers and dealers. Standby generators are sold by dealers and by retailers, including online.
Installing a standby generator is a job for licensed trades, with permits. Generac says it has a large dealer network and groups dealers into tiers by what they can do. Not every dealer installs or services, so ask. Our guide to Generac dealers explains the tiers.
A portable generator needs no installation to run tools from extension cords. To power circuits in your house, it needs a transfer switch or an interlock fitted by a licensed electrician. Never plug a generator into a wall outlet.
30. Has Generac had recalls?
Yes. Like most large manufacturers, Generac has issued recalls and product notifications, and it lists them on a recalls page on its website. When we checked, the page included notices for certain portable generators and pressure washers. It also said that owners of air-cooled home standby generators larger than 13 kW made between 2008 and 2015 are eligible for a one-time, no-cost inspection of a fuel system part for corrosion. Check the page with your model and serial number.
Standby or Portable: A Quick Comparison
| Point | Home standby | Portable |
|---|---|---|
| Starts | Automatically | By hand or button |
| Fuel | Natural gas or propane, piped in | Gasoline or propane you carry |
| Typical power | 10 to 28 kW | 2,200 to 9,500 watts for most models |
| Noise | 65 to 67 dB, per Generac | Quiet for inverters, loud for open-frame |
| Installation | Licensed trades and permits | None for cords. An electrician for a transfer switch |
| Routine service | Every 200 hours or 2 years | Every 100 hours |
| Works when you are away | Yes | No |
Our guide to portable vs standby generators explains the choice in more depth.
Parts That Answer the Most Common Problems
Most generator problems come down to oil, filters, a battery or stale fuel. These items deal with those. We have not tested them. Details come from the sellers’ listings.
For 20 to 26 kW standby units
Generac 6485 Scheduled Maintenance Kit
A genuine Generac kit for 20, 22, 24 and 26 kW air-cooled standby generators with the 999 cc V-twin, built in 2013 or later. Oil is not included.
- Fits20 to 26 kW air-cooled, 2013 or later
- Engine999 cc V-twin
- IncludesAir filter, pre-cleaner, oil filter, 2 spark plugs
- Also includesFunnel, cloth, reminder sticker, instructions
- IntervalEvery 200 hours or 2 years
- OilNot included. 5W-30 full synthetic
- Why it works: every part for a scheduled service is in one box, with instructions.
- Who it is best for: owners who do their own service, and anyone who wants a kit ready for a long outage.
- What it solves: a yellow maintenance light and a search for the right filters.
- Keep in mind: buy the oil separately. Check your generator’s size, engine and year against the listing before you order.
As an Amazon Associate we earn from qualifying purchases. Details come from the Amazon listing, checked October 2026.
For 12 to 18 kW standby units
Generac 6484 Maintenance Kit for 12 to 18 kW Generators
The matching genuine kit for Generac’s mid-size air-cooled standby generators with 760 to 990 cc engines, built in 2013 or later.
- Fits12 to 18 kW air-cooled, 2013 or later
- Engine760 to 990 cc Generac
- IncludesAir filter, pre-cleaner, oil filter, 2 spark plugs
- Also includesFunnel, chamois, sticker, manual
- IntervalEvery 200 hours or 2 years
- OilNot included. 5W-30 full synthetic recommended
- Why it works: genuine parts with the right part numbers for this engine family.
- Who it is best for: owners of 12, 14, 16 and 18 kW Generac standby generators.
- What it solves: guessing at filter and plug numbers.
- Keep in mind: oil is sold separately. Confirm the engine size and model year on your data label first.
As an Amazon Associate we earn from qualifying purchases. Details come from the Amazon listing, checked October 2026.
For portable owners
STA-BIL Storage Fuel Stabilizer, 32 oz
A gasoline stabilizer for stored fuel. The maker says it keeps gasoline fresh for up to 24 months, at a rate of one ounce to 2.5 gallons.
- Size32 fluid ounces
- Dose1 oz per 2.5 gallons
- Maker’s claimFresh for up to 24 months
- TreatsUp to 80 gallons
- UseStored gasoline and fuel left in the tank
- Stock on listingIn stock when checked
- Why it works: it slows the breakdown that Generac says begins within about a month.
- Who it is best for: anyone who keeps gasoline in cans or in a generator’s tank.
- What it solves: a gummed carburetor, the most common reason a portable will not start.
- Keep in mind: add it to fresh fuel. It cannot rescue fuel that has already gone bad. The 24-month figure is the maker’s claim.
As an Amazon Associate we earn from qualifying purchases. Details come from the Amazon listing, checked October 2026.
For every home
Kidde Carbon Monoxide Alarm with 10-Year Sealed Battery and Digital Display
A battery-powered carbon monoxide alarm with a digital display. It keeps working when the power is out, which is exactly when a generator is running.
- Power10-year sealed lithium battery
- DisplayDigital, updates every 15 seconds
- Alarm85 dB
- SensorElectrochemical
- MemoryPeak level
- BrandKidde
- Why it works: it warns you about a gas you cannot see or smell.
- Who it is best for: every home with any kind of generator.
- What it solves: exhaust drifting indoors unnoticed.
- Keep in mind: an alarm is a backup to correct placement. If it sounds, get everyone outside and call for help.
As an Amazon Associate we earn from qualifying purchases. Details come from the Amazon listing, checked October 2026.
Common Mistakes Generac Owners Make (and the Fix)
Pro Tips From Generac’s Guidance
- Register your generator. It links the warranty to you and speeds up service.
- Keep a maintenance kit on the shelf. After a storm, parts sell out.
- Never start a generator under load. Generac’s support articles repeat this. Switch loads on after it is running.
- Run a portable on level ground. A low-oil switch can trip on a slope.
- Check the recalls page when you buy, and again each year.
- Save the dealer’s number before storm season.
- Write codes down. A photo of the display is even better.
Real-Life Scenarios: What Would You Do?
These are typical situations. They are examples, not reports from real customers.
💡 The yellow light in spring
Your standby unit shows a flashing yellow light, but it ran fine last month.
It is a warning or a maintenance reminder. Read the code on the panel or in the app, and book or do the service.
Action: service it now
🔴 The red light in a storm
The generator tried to start and stopped. The code says overcrank.
Check that the fuel valve is on and look at the propane gauge. Clear the alarm once and try again. If it returns, call a dealer.
Action: check fuel, then call
⛽ The portable that sat all year
You pull the cord twenty times and it will not fire.
Suspect stale fuel. Drain the tank, add fresh gasoline and check the plug. The carburetor may need cleaning.
Action: fresh fuel first
Generac Generator: Quick FAQ
How long will a Generac generator run without stopping?
Generac says a home standby generator runs as long as fuel is available and it is maintained. Check the oil for every 24 hours of use. A portable runs until its tank is empty. Generac lists about 9 to 11 hours at half load for its open-frame GP models and about 4.5 hours for its smallest inverters.
How loud is a Generac generator?
Generac says its home standby generators average 65 to 67 decibels, similar to a central air conditioner. Its inverter portables are much quieter, and its open-frame portables are louder.
What does a red light on a Generac generator mean?
A steady red light means the generator is switched off. A flashing red light is an alarm: a fault has been detected and the generator will not run until it is cleared. Read the code before you clear it.
How often should a Generac generator be serviced?
Generac's maintenance kits for standby generators are labeled for every 200 hours or 2 years. For portables, Generac says to change the oil after the first 20 to 30 hours and then every 100 hours.
What kind of gas does a Generac portable generator take?
Clean, fresh unleaded gasoline with a minimum of 87 octane, according to Generac's portable FAQ. Do not store fuel in the tank for more than 30 days without stabilizer.
Is Generac a good brand?
Generac is the largest name in home standby generators and has a very wide range and dealer network. It has also had recalls, as most large makers have. The right choice depends on your needs and on the quality of the dealer near you.
Your Generac Owner’s Checklist
- Photograph the data label with the model and serial number.
- Register the generator with Generac.
- Know your lights: green ready, yellow warning, red alarm.
- Check the oil before storm season and every 24 hours of running.
- Keep the propane tank above 30%, if you use propane.
- Service a standby unit every 200 hours or 2 years.
- Change a portable’s oil at 20 to 30 hours, then every 100 hours.
- Drain or stabilize gasoline before storage.
- Run portables outdoors only, well away from the house.
- Fit carbon monoxide alarms on every level of your home.
- Write down any code before you clear it.
- Save your dealer’s number.
The bottom line
Most Generac questions have short answers: keep the oil up, keep the fuel fresh, read the light before you clear it and run every portable outdoors. Do those four things and a Generac generator will usually be ready when you need it.
As an Amazon Associate we earn from qualifying purchases.
Sources: Generac’s home standby generator FAQ, portable generator FAQ, home standby and Mobile Link pages, recalls page and product pages (generac.com); Generac support articles on status LEDs, error codes, clearing alarms, overcrank, low oil pressure, low battery, overload and portable troubleshooting (support.generac.com); Amazon listings for the Generac 6485 and 6484 maintenance kits, STA-BIL Storage and the Kidde carbon monoxide alarm. All checked October 2026.
