How loud is a generator?

Why a generator’s noise level is important

When buying a backup generator, there are a lot of considerations, from the generator’s size to its fuel source to its price. One factor homeowners sometimes forget, however, is noise. Like any internal combustion engine, a generator can be loud, which may irritate your neighbors and take away from your family’s peaceful state of mind. If it’s too loud, you may get an angry letter from your local homeowner’s association, or worse yet, you could be violating city ordinances. It’s thus important to understand how loud your generator is before you buy it.

Before you buy a generator, search for your city’s local noise ordinance or code. If you can’t find it online, contact your local city hall directly. Keep in mind that regulations may vary based on time of day and whether you live in an urban, suburban, or rural area. Once you find out how loud your generator can legally run, you’ll be in a better position to find out which generator is best for you. The noise level of a generator depends on a range of factors, including its type, fuel source, size, brand, and noise-cancelling features. 

If a generator’s noise level is important to you or local codes restrict the noise level of your generator, the first thing you should consider is the size of your generator. In general, the larger a backup generator is, the more noise it will produce. Finding a generator that matches your electrical needs is thus important to keeping the noise level down. To find out the ideal size of your generator, consider using AlltimePower’s free backup power calculator. You’ll be able to determine how large your generator needs to be based on the appliances you want to use during an outage.

How loud is a backup generator?

Before diving into the numbers, it’s important to understand how sound is measured. Unlike most measurements, decibels (dB) are measured on a logarithmic scale with a base of 10 rather than a linear one. That means that 20dB is twice as much as 10dB, and 30dB is four times as much as 10dB. In other words, for each increase of 10 decibels, the noise level doubles. 

With that in mind, the average backup generator measures between 60 and 70 decibels when heard from the industry standard of 7 meters (23 feet) away. That’s somewhere between the noise level of a dishwasher and a vacuum cleaner. If you want to find a quiet backup generator, start by determining the smallest generator you need to run essential appliances, since smaller generators are usually quieter than larger ones.

Next, you should compare brands and models to find a generator you like at a reasonable noise level. Compare similarly sized models, and be sure they are all measured at the industry standard of 7 meters (23 feet) away. On the lower end of the noise range, Cummins Power Generation produces just 62dB when heard 23 feet away. Briggs and Statton generators weigh in at 64dB, while the Generac Guardian line measures 66dB. On the higher end, Kohler Power Systems generators produce 69dB. 

How loud is a portable generator?

Despite their smaller size, portable generators are usually louder than residential backup generators. This is because the portable and cheaper design means that they often contain fewer noise-cancelling features, such as efficient mufflers, rubber pads, and soundproofing casing, that their non-portable and more expensive counterparts contain. Any loose nuts or bolts inside the generator can also increase the vibrations and thus make it louder.

Most portable generators have a noise level between 70dB and 100dB when heard from 23 feet away. Remember that 100dB is 8 times as loud as 70dB, so that’s a large gap. 70dB is approximately equivalent to the noise level in a busy restaurant, while 100dB is like listening to an MP3 player at full volume. At 85dB, a generator can cause hearing damage after 2 hours of exposure, while a generator at 100dB can cause hearing damage after just 15 minutes.

How loud is an inverter generator?

Though most portable generators are very loud, one type of portable generator is actually quieter than most backup generators: an inverter generator. The engine in an inverter generator is designed specifically to reduce noise. In addition to using fuel as a power source, an inverter generator includes a battery, an alternator, and an inverter. The generator uses this electrical current to throttle the engine up and down rather than having it run at full tilt the whole time, which increases its efficiency and keeps it quiet.

Most inverter generators produce about 50-60dB, which is lower than both backup and traditional portable generators. That’s approximately equivalent to the decibel range of an average conversation between two people. Because inverter generators are quieter and more efficient, they tend to be more expensive than many other portable generators, but many homeowners find them worth the extra cost.

There are a number of different brands to choose between when it comes to inverter generators. The Honda EU2200i is an excellent inverter generator model that can run as low as 48dB when at ¼ load, or 57dB at full load. The Westinghouse iGen2200 is another popular model that runs as low as 52dB and is fully CARB compliant. Finally, the Briggs & Statton P2200 runs at 59dB and is designed with tailgating and camping in mind.

Noise-cancelling features

The difference in decibel rating between similarly sized models often comes down to the noise-canceling features different brands may use. An engine that minimizes internal vibration through the use of rubber material and a silencer on the exhaust can help reduce noise. Additionally, some manufacturers use cool air attenuation to reduce the noise of the engine. In these generators, air is sucked into and forced out of the engine and made to pass through 90-degree bends, muffling the noise from the machine.

Some generators also have a sound-absorbing enclosure. If the enclosure is made of aluminum or galvanized steel, it will do little to reduce noise. However, effective sound absorption material that absorbs rather than vibrates with the generator can significantly lower sound levels. A sound-absorbing enclosure can be bought after a generator has been installed, although it’s important to make sure the enclosure fits the generator well. 

There are also differences when it comes to fuel. As a general rule, diesel-powered engines are louder than their propane- or natural gas-powered counterparts. Generators that burn fuel more efficiently tend to be quieter. Using a home battery system in conjunction with or instead of a fuel-powered generator is another way to dramatically reduce noise levels. Home battery systems such as the Tesla Powerwall produce an electronic humming sound at about just 50dB, quieter than most generators. 

Finding the ideal generator location

You can limit the negative effect of a generator’s noise level by placing it in an ideal location. Many homeowners place their backup generator on the side of their home, away from bedrooms and living spaces but close to their home’s electrical panel. You’ll want to consult with your electrician before deciding where to install it. Local codes may also require you to place it at a certain distance away from your neighbors home. 

If you own a portable generator, you’ll have more freedom as to where you want to run it. Electrically, you simply need extension cords long enough to reach the generator. If you have enough space in your yard, you may want to run the generator far from your home to reduce noise levels. To further reduce noise, point the exhaust away from your home (which you should do anyway for safety reasons). If pointing the exhaust pipe away from your home would point it toward your neighbor’s house, point it up toward the sky instead. 

Other ways to reduce a generator’s sound

Once you install your generator, there are a few ways you can reduce its noise level. For example, some homeowners install acoustic barriers around the generator that will absorb some sound. These barriers may be movable or permanent, and they can come in different materials. Typically, rigid barriers like a concrete wall or sand-filled blocks absorb sound better than more flexible materials, such as wood, do.

Another way to absorb sound is by installing an isolation mount made of rubber-type padding. The mount will keep the vibrations from the generator from spreading from one material to another, which will lower the sound. Sometimes, isolation mounts and acoustic barriers may absorb sound at or above the frequency of 100hz but not absorb much sound below that threshold. As a result, the sound that makes it through may sound deeper, like a low rumble.  To learn more about how to buy the perfect generator for your home, try using Alltime Power’s backup power calculator. This free resource will allow you to calculate how large and expensive of a generator you need based on your home’s power usage. You’ll also have the chance to find reputable generator dealers in your area who sell generators that fit your needs.

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