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What is a CARB-Compliant Generator?

What is a CARB-Compliant Generator?

When the electricity is turned off, a portable generator can provide backup power to your home or business. Generators are internal combustion engines much like auto motors. But instead of propelling vehicles, they generate electricity that can run lights, fans, heaters, or other appliances during a power outage. 

Like any engines that burn combustible fuel, power generators can produce toxic fumes that are released into the atmosphere. And, in the state of California, that’s where CARB comes in.

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What is CARB and What Does It Do?

In this case, CARB has nothing to do with a carburetor (although that’s a good guess where engines are concerned). It has everything to do with a state that has been fighting to preserve and improve its air quality for decades.

What is CARB?

CARB stands for California Air Resources Board, the state organization responsible for maintaining clean air in California. Established in 1967 (three years before the Environmental Protection Agency), CARB oversees air pollution control efforts in California. Its mission is to gather air quality data, reduce air pollutants, and develop programs to fight climate change. 

Fourteen other states have adopted CARB regulations. These include Colorado, Connecticut, Delaware, Maine, Maryland, Massachusetts, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Vermont, and Washington.

What Does CARB Do?

Simply put, CARB tries to limit California’s air pollution caused by these harmful gases in the atmosphere:

  • Carbon monoxide — A colorless, odorless gas, CO can cause dizziness, confusion, headache, vomiting, chest pain, and even death. CO detectors help reduce this risk. The threat of CO poisoning is why you don’t want to put a generator in your home or garage. 
  • Nitrogen oxides — These are seven gases and compounds made up of oxygen and nitrogen, abbreviated as NOx. One of them is nitrous oxide, or “laughing gas,” which contributes to global warming. The most common are nitric oxide and nitrogen dioxide.
    Nitrogen oxides are also produced by cigarettes and found in rocket fuel. They help contribute to the formation of smog. Exposure can cause coughing, choking, eye/skin irritation, and headaches. Long-term exposure can lead to asthma and respiratory infection.
  • Sulfur oxides — Sulfur oxides also cause a variety of health problems. Breathing in sulfur dioxide can trigger asthma attacks and other breathing problems. Long-term exposure can lead to respiratory illness and aggravate heart disease.
    Chemical compounds in this group don’t just cause health problems in humans; they can harm the environment, too. Sulfuric oxides react with other substances to produce acid rain. And at high concentrations, they can stunt the growth of trees and other plants
  • Reactive organic gases — These include carbon dioxide, a naturally occurring part of the planet’s ecosystem that plants use in photosynthesis. However, it’s also a greenhouse gas that builds up in the atmosphere from burning fossil fuels.
    Too much CO2 can reduce air quality by removing oxygen from the atmosphere. The results can include fatigue, headache, and labored breathing.
  • Particulate matter — Particulate matter is a mix of solid particles and liquid droplets produced by numerous different chemicals. Some are microscopic; others, large enough to see with the naked eye. Common particulates include soot, smoke, dust, and dirt. They can cause hazy skies and difficulty breathing, even entering your bloodstream.

To improve the air quality index, CARB regulates all engines in the state that burn gasoline, diesel, natural gas, or propane. These include cars, trucks, semis, tractors, lawnmowers, chainsaws, heavy machinery — and, yes, gas, propane, and diesel generators. 

How is CARB Different from the EPA?

The Environmental Protection Agency is the environmental watchdog agency for the federal government. The EPA has its own guidelines for the manufacture, sale, and import of internal combustion engines in the United States.

EPA air quality regulations may or may not overlap with CARB guidelines. CARB rules are usually stricter than EPA rules. This means, if you live in California, it often isn’t enough to comply with EPA regulations. You also have to follow the rules set forth by CARB. 

Many generators come labeled as “CARB-compliant.” Look for those even if you don’t live in California. They’re better for the environment and legal for use everywhere in the United States.

What is a CARB-Compliant Generator?

The California Air Resources Board was created to devise and enforce limitations on harmful greenhouse gas emissions. Generators are engines that burn combustible fuels; it’s impossible to keep such emissions from entering the air while operating one. These facts created a “rock and a hard place” situation that CARB was forced to address.

To balance these conflicting forces, CARB drew up criteria for energy-efficient engines that could produce as few pollutants as possible. This led to the manufacture and certification of CARB-compliant generators.

A CARB-compliant generator runs more efficiently and produces fewer greenhouse gas emissions than a non-CARB-compliant generator. This results in better air quality. Because CARB standards are stricter than most, CARB-compliant generators are seen as the most environmentally friendly and safest generators available.

Why Does a Generator Need to be CARB-Compliant?

Generators need to be CARB-compliant so people can use standby power without destroying the environment or their health. Here’s an example: 

Wildfires are an ever-present, growing threat in California. Fifteen of the 20 most destructive fires in the state’s history have occurred since 2000. So electric utilities sometimes de-energize their lines to reduce the chance of sparking a fire. 

But prolonged loss of power is dangerous for vulnerable individuals. It also disrupts operations for hospitals, fire departments, police stations, water utilities, gas stations, grocery stores, and other public service providers. 

Consequently, CARB regulations allow backup generators to replace lost grid power. But because they burn combustible fuels with heavy greenhouse gas emissions, generators can reduce air quality and endanger public health.

CARB-compliant generators address all of these issues at once, resulting in environmental, health, and financial benefits. Even if you don’t live in California, choosing a CARB-compliant fuel generator can provide advantages in these areas:

  • Longer-lasting, cleaner power — Any power equipment can produce standby electricity during an outage. CARB-compliant generators are built to supply cleaner power for longer periods. 
  • Reduced air pollution — Users don’t have to sacrifice their environment if they need backup power during an outage.
  • Lower health risks — Cleaner-running generator engines pose less of a health hazard to people with respiratory or cardiac conditions.
  • No risk of sanctions — The sale or purchase of a noncompliant generator can trigger a fine. The amount depends on state, district, or local regulations.
  • Higher-quality machinery components — Parts for CARB-compliant generators are built for enhanced fuel efficiency, reliability, and the cleanest operation possible.

How Does CARB Regulate Generators?

CARB regulations for stationary and portable generators were developed in collaboration with the state’s local air districts. These districts are responsible for safeguarding regional air quality. 

CARB regulations seek to limit small, off-road engines (often referred to as SORE) from releasing pollutants into the atmosphere. These control pollution from three sources:

  • Exhaust emissions — Inefficient burning of fossil fuel results in exhaust emissions containing most of the pollutants listed above. Carburetors, fuel injection, crankcase vent lines, and other electronic controls ensure cleaner and more complete burning of fuel.
  • Evaporative emissions — Gas evaporates from a fuel tank or lines, taking reactive gases and hydrocarbons with it into the atmosphere. Changes in materials, as well as carbon-canister or pressure-relief valve systems, help keep the gas inside the engine.
  • Spillage — Fuel leakage or spillage during use or refills releases toxic gases and hydrocarbons. Updated designs and standards for fuel caps and gas cans limit this type of pollution.

Manufacture and Certification of Small, Off-Road Engines (SORE)

CARB regulations make sure that small, off-road engines are built to ensure clean running, energy efficiency, durability, and reliability.

Manufacturers of standby generators and other small engines are responsible for having their products certified by CARB and the EPA. This involves several steps:

  1. First, manufacturers register with the EPA and CARB.
  2. Next, they group their engines into exhaust families and evaporative families depending on components. 
  3. They test each engine according to regulation specs and record the test results. Then they submit the resulting documentation to CARB and the EPA.
  4. If an engine passes the necessary tests, it gets certification from the EPA and CARB.
  5. Manufacturers label each engine accordingly on an emissions-control label, as required.
  6. Once an engine is certified and labeled, the manufacturer can start selling it in California.

Purchase and Use of Small, Off-Road Engines (SORE)

For consumers, the responsibility of CARB compliance lies mainly in their purchase of a generator, not the use of it. Small standby generators and other small engines must be CARB-certified to be legally sold in California. 

CARB doesn’t place restrictions on the use of certified backup generators if they’re small enough. But often these are still subject to requirements from the local air districts. This can include permitting requirements, emission limits, and operating restrictions. 

The smallest portable generators less than 50hp also are generally exempt from air district rules. Owners should check with their air district to determine if there are established usage limitations or permit requirements on their generator.

During emergency outages, generators can be crucial. It’s important to know what kind you can operate, and what rules you need to follow when using them. 

To read the regulations for various types of generators in California, visit the generator section on the CARB website. Users also should contact their air district (California has 35 of them) to make sure they’re complying with permitting requirements.  

How Can You Tell if a Generator is CARB-Compliant?

To discern whether your generator complies with CARB regulations, you can consult these resources:  

  • Emissions label — If you’re comparing generator models in person, check the engine emissions label on each machine.

    The label on CARB-compliant equipment will read: “This engine meets U.S. EPA EXH/EVP and California SORE EXH/EVP regs for [year].” There also should be an indication of the generator’s levels of Air Index and Emissions Durability.

  • Manufacturer’s website — Check the manufacturer’s website of each generator you’re interested in. If it meets the specifications, the manufacturers will list CARB compliance among the features. 
  • Retail listings — You can usually find CARB compliance among the product features listed online by home improvement retailers, too. 

If your state requires CARB compliance for gas-powered equipment, confirm that a generator is CARB-certified before you buy it. 

Decoding Engine Emissions Labels

If you’ve ever looked at an emissions label on a  generator or other engine and wondered what all the letters and numbers mean, ponder no more. The EPA and California Air Resources Board use standardized codes to identify important features of engines and their emissions. 

It took a lot of digging, but we’ve cracked the code for you. Here’s how to read the codes on an engine emissions label.

What Is a CARB Compliant Generator infographic

Engine Family Code

There are usually two 8-12 character codes on an engine emissions label. The first is the EF, or Engine Family code. 

Let’s use this as an example:


EF: = The first pair of letters stands for the words “Engine Family.” Each engine belongs to a “family” whose members all share the same drive-train and emissions characteristics. 

G = The first letter after the colon reveals a code representing the model year, or what year the engine was built. (G = 2016, H = 2017, J = 2018, etc.)

HNX = The next three letters represent the manufacturer code, or the name of the company that made the engine. (HNX stands for Honda, BSX for Briggs & Stratton, YMX is Yamaha, etc.)

S = The next single letter represents the industry sector code. (Most portable standby generators fall into the sector of small, non-road, spark-ignition engines under 19 kilowatts, represented in this code by the letter S.)

.389 = The three-digit number preceded by a decimal point tells you the code for engine displacement, which is measured in liters or cubic centimeters (.389 liters is 389 cc).

2 = The final digit stands for the engine class. Generators are considered “non-handheld equipment engines” with displacement capacities that can range from less than 100 cc to more than 225 cc. (The code 2 stands for a non-handheld equipment engine greater than 225 cc displacement.)

AB = The final two letters in the code represent the name the manufacturer has designated for this engine family.

Evaporative Family Code

The second sequence of letters and numbers is the EVF, or Evaporative Family code, which describes certain characteristics of the engine’s fuel system and fuel evaporation safeguards. 

Here’s an example:


EVF:  = The first three letters before the colon stand for the words “Evaporative Family,” referencing the set of standards for the fuel and evaporative systems that each engine adheres to.

C = The first letter after the colon stands for the venting control type used to vent fumes from the engine’s fuel system. (C stands for carbon canister, S for sealed tank, etc.)

M = The next single letter represents the tank barrier type, or the material used to insulate the fuel tank and keep the fuel inside. (There are many types and corresponding codes that can be used, such as M: metal, P: plastic, C: co-extruded, L: selar, N: nylon, A: acetal, or O: other)

HNX = Just as in the EF code, the next three letters represent the manufacturer code, or the name of the company that made the engine. (HNX stands for Honda, BSX for Briggs & Stratton, YMX is Yamaha, etc.)

2 = The first single numeral represents the engine class, just as in the EF code. (The code 2 stands for a non-handheld equipment engine greater than 225 cc displacement.)

2A = The final numeral and letter are the manufacturer’s unique code or identifier for this particular engine in this evaporative family.

Features of a CARB-Compliant Generator

Different CARB regulations apply to different models and fuel types, but several features are common to most CARB-compliant generators. 

  • Transfer switch — All generators should connect to their facility via a transfer switch, which directs the electricity safely. CARB-compliant generators generally come transfer switch-ready for easier setup.

    A transfer switch is a small board that looks like a circuit-breaker panel. It can connect your home to utility power or to your generator, but not both at the same time.

    The switch guarantees that electricity flows in just one direction. Without it, power can circulate back to fry appliances or blow out your generator. It can even enter utility lines, potentially electrocuting utility workers in the area. That’s why backfeeding is illegal

    Manual transfer switches are less expensive, but an automatic switch makes the transfer for you. You don’t need to be at home when the power goes off or comes back on. That could be worth the extra money.

  • Watts rating — It’s important to know a generator’s capacity so you can calculate the appliances it can power. The more watts your portable generator supplies, the more systems and appliances you can run at the same time.

    You’ll need to know two different numbers for each appliance: running watts and starting watts. Running watts are the number of watts needed to keep something running. But you’ll also need extra power for two or three seconds to get it started. This higher figure is called starting watts (also surge or peak watts).

    If you don’t know the wattage an appliance needs, multiply volts by amps to figure it out. Here are a few sample items you might need to power, with their respective running and starting watts:

    • 60-watt lightbulb:  60 watts running / 0 watts starting
    • Television, 27 inches:  500 watts running / zero watts starting
    • Refrigerator:  700 watts running / 2,200 watts starting
    • Computer with 17-inch monitor:  800 watts running / zero watts starting
    • Washing machine:  1,150 watts running / 2,250 watts starting
    • Dishwasher:  1,500 watts running / 1,500 watts starting
    • Electric water heater:  4,000 watts running / zero watts starting

    To determine the wattage you’ll need, add up all the running watts of the items you want to run. Then, on top of this, add the largest additional starting watts of the largest systems or appliances on your list. 

    To run all these items, you’d need 8,710 running watts, plus the starting wattage of the largest appliance. 

  • Multiple start mechanisms — Many generators offer some combination of recoil start, electric start, and remote start mechanisms. 
    • You can start an electric start generator with the push of a button or the turn of a key. 
    • A recoil start takes physical effort (and, sometimes, patience). Another name for it is a pull start, like the one on your lawnmower.
    • A remote-start generator operates via remote control, which is convenient if it’s raining or snowing. You can start your generator from inside your home or under a covered patio. Remote starters also have status lights to alert you if something’s wrong with your generator.

    Some models only provide one way to start your generator. Multiple-start mechanisms give you more flexibility.

  • Dual fuel capacity — Some generators can be powered by either gas or propane, making them more functional. This can provide versatility if one kind of fuel is readily available, and the other isn’t.

    One fuel not on the list is gasoline. It’s volatile; can’t be stored easily in large quantities; and can’t be used easily with another fuel.

  • Reinforced fuel tank — Evaporation of gas from a fuel tank is a common way that generators release pollutants into the air. CARB-compliant models employ reinforced construction or specially treated materials to inhibit evaporation. Some come with a built-in fuel gauge for added accuracy. 
  • Hour meter — A meter measuring a generator’s runtime can be helpful for scheduling maintenance and keeping track of emissions durability. This delineates how many hours an engine can operate and still maintain its emissions compliance. Regular upkeep can extend that time. 
  • Low-oil overload shutdown — Many generators offer an automatic shutdown feature that kicks in when the oil level gets too low. To prevent damage, the engine shuts off before it seizes. On some models, an alarm sounds. 
  • Overhead valve engine or OHV — These feature a more compact design and produce a higher power output than other engines. Intake and exhaust valves are in the head of the engine cylinder, instead of mounted on the engine block.
  • GFCI receptacles — Ground-fault circuit interrupters prevent electric shocks by shutting down the machine if a ground fault is detected. A ground fault occurs when electricity seeks another path to ground outside a system’s wires.

    It can be caused by loose connections, miswiring, or worn insulation. During a ground fault, the flow of power increases dramatically, because it’s no longer restricted by wiring. A GFCI works by cutting power when it detects any such disruption in electrical current.

  • Noise suppression — Generators are infamous for being noisy — sometimes so noisy that they violate noise ordinances and contribute to hearing loss.

    Portable inverter generators are more expensive, but they reduce noise levels drastically. They limit shaking inside the generator casing and keep the engine running at a constant rate. Besides being quieter, they’re often smaller, lighter, and more efficient than conventional generators. Most are CARB-compliant, too.

  • Warranty — A limited warranty safeguards your generator if repairs need to be made.

Can I Use a Non-CARB-Compliant Generator in California?

The short answer is actually two answers: Yes, you can use one — but no, you can’t buy one. 

CARB rules don’t restrict you from using a non-CARB-compliant generator in California if you already own one. However, you are not permitted to sell or buy non-CARB compliant generators of any size or model in the state. 

Before you use your generator, check with your air district to make sure you can comply with its permitting and operating requirements.


Using a CARB-compliant generator isn’t just the law in California, it’s a good idea overall. It can keep you safer from substances that pose health risks, and it can help the environment, too. By reducing pollutants in the atmosphere, CARB rules help protect trees that provide the oxygen we breathe. They can even help protect the ice caps, staving off global warming. 

With the mounting risk of wildfires (and accompanying outages), reliable emergency power is more important than ever. CARB-compliant generators can supply that power. They also can help you stay on top of maintenance, guard against backfeed, and stay safe from electric shock. They can be a great investment in your health, the environment, and your peace of mind.

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