What Is a Decibel?

By Anne Fonda

A decibel (dB) is a measurement of how intense (loud) a sound is. The decibel scale is logarithmic, meaning that a 10 dB increase in noise level corresponds to a tenfold increase in sound intensity. But for the human ear, the difference is perceived as being only twice as loud.

Decibels are measured using a decibel meter. Decibel ratings are expressed as dBA, or A-weighted. This simply means this is how loud a sound is perceived by the human ear. The following decibel chart gives examples of some common sounds/noises and their decibel level. 

This information comes from the Centers for Disease Control and Prevention (CDC).

When it comes to your outdoor AC unit, you don’t want it to be so loud that you can’t have a conversation with your neighbor without yelling.

First, we should say that older air conditioners and heat pumps are louder than comparable new units. That’s because technology has changed, and people (and municipalities) care more about noise levels. We’ll discuss the main factors that determine a new condenser unit’s noise level. 

The decibel rating for American Standard’s HVAC equipment is listed as “nominal sound dBA.” The nominal dBA describes the noise level during normal operation.

Single-stage air conditioners and heat pumps generally have a higher dB rating because they turn on and off at full power. For example, the Silver 14 Air Conditioner has a nominal sound of 72-73 dBA.

Meanwhile, variable-speed units have a large range, because the fan can run at so many different speeds. They are much quieter at the lower speeds. For example, the AccuComfort™ Variable Speed Platinum 20 Air Conditioner has a nominal sound of 55-75 dBA.

Quality air conditioner manufacturers like American Standard® include a compressor sound insulator in their premium AC units to reduce operating noise for a quieter home environment. Some other models may not include a sound insulator, and will therefore be louder.

Most outdoor condenser units are installed right next to your home. An exterior wall can help deaden the sound, making a unit seem quieter than the same unit that is installed on a platform next to your patio.

Once you have a unit installed, yearly maintenance is needed not only to keep the system running efficiently but also to maintain the sound level. As condenser units run, normal wear and tear can cause issues with loosening bolts, fan blades, or other parts. This can increase how much noise the unit makes. An HVAC technician can easily resolve these problems during an AC tune-up.

When the noise your AC unit makes is a factor in which unit to buy, be sure to check the decibel ratings. Decibels are measured using a decibel meter, or sound meter. For the most accurate levels when testing, there should be minimal background noise. That’s why American Standard® units are tested in our SEET  (System Extreme Environmental Test) Lab Sound Rooms. 

We have three sound rooms (including a Hemi-Anechoic Chamber that’s structurally isolated from the surrounding building and insulated for sound) dedicated to testing the sound quality and power of our equipment and isolating potential sound problems. Our completely soundproof Reverberation Chamber is used to determine the acoustic performance of our products.

American Standard® has two units that are quieter than the rest.

The AccuComfort™Variable Speed Platinum 18 Air Conditioner is a great choice for both energy efficiency and quiet operation. It’s a variable speed unit with a nominal sound of 55-75 dBA.

Our quietest cooling unit is a side-discharge heat pump rather than a traditional AC unit. The AccuComfort™ Platinum 19 Low Profile Heat Pump was specifically designed for densely populated urban areas that require a low-profile design. At the same time, we designed it to be ultra-quiet to meet or exceed low sound requirements that exist in cities with strict sound regulations. The nominal sound for this unit is 43-57 dBA.

For product recommendations for your home, contact your local American Standard dealer. They may even be able to give you names and contact information for references who have the units you are considering where you could get permission to go listen to how loud or quiet the unit is.

A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need. 

She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism. When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.

Expert review by Kimberly Sexton, Senior Systems Engineer