Why Your IEQ Monitor Should Measure Sound, Too

Most IEQ monitors track air quality, temperature, and humidity, and some track light, but very few measure sound, the factor office occupants complain about most. A multi-parameter IEQ monitor with sound closes that gap by adding acoustic data to the IEQ factors you already track.

Here’s what the research says about how noise affects occupant well-being and productivity, what to measure for sound, and what you gain by measuring all four IEQ factors on one platform.

Why Should an IEQ Monitor Measure Sound?

An IEQ monitor should measure sound because acoustics is the most common source of dissatisfaction office occupants report, yet most IEQ monitors track only air quality (CO2, PM2.5, and VOCs), temperature, humidity, and sometimes light.

For example, in a UC Berkeley Center for the Built Environment study of 62,360 occupants across 617 office buildings, 54% named at least one acoustic issue as a source of dissatisfaction, compared with 38% for temperature. Research from Leesman arrived at a similar conclusion, with 70% of employees calling noise levels an important workplace factor, while only 35% reported satisfaction with them.

That dissatisfaction has measurable costs for occupant well-being and productivity:

• Stress builds before people notice it. In a Cornell field experiment, three hours of low-level open-office noise raised clerical workers' epinephrine (a stress hormone), even though they didn't report feeling more stressed. They also made 40% fewer attempts at an unsolvable puzzle, a sign of lower motivation.
• Noise annoyance is linked to anxiety and depression. A five-year study of over 11,000 adults found that each increase in daytime noise annoyance was associated with a 13% higher risk of developing depression and an 11% higher risk of developing anxiety. The study looked at noise from traffic, aircraft, industry, and neighbors, not workplace noise, but it shows how persistent noise annoyance can affect mental health.
• Noise drains memory and energy. Raising open-plan noise from 39 to 51 dB LAeq for about two hours worsened word recall and left participants more tired and less motivated.
• Overheard speech cuts performance. A model built from more than 30 lab studies puts the drop in cognitive performance from intelligible speech at 7% as a deliberately conservative floor, with losses in the underlying studies reaching 41%.
• Employees feel the productivity cost. In a U.S. GSA survey of 3,700 federal employees, 60% said they'd get more done if their workplace were quieter.

Because of these consequences, building standards already recognize sound as a core part of indoor environmental quality. The WELL Building Standard, for example, gives sound its own concept alongside air, light, and thermal comfort to ensure buildings maintain an acoustic environment that helps, rather than harms, occupant well-being.

Just like all other factors impacting IEQ, you can't fix an acoustic problem that you haven't measured, and the costs of acoustic issues add up fast. An IEQ platform that only tracks temperature or air quality but not sound has no visibility into the factor occupants complain about most, or into what it's costing their well-being and productivity.

What Should You Measure When You Add Sound?

Not all sound sensors are created equal, and some don't measure the range of data needed to understand acoustic comfort, which is why any sensor you choose should measure three parameters: level, variability, and frequency. These measurements also need to be continuous, since a one-time assessment or an average level taken over several hours can't capture how a space actually sounds throughout the day. Here are the specific metrics to look for in a sound sensor:

1. Level: how loud a space is overall. It's the difference you'd notice walking from a quiet library into a busy restaurant. A sensor should report level in three ways:

• LAeq: the A-weighted energy average of sound over time, weighted to match how human hearing perceives loudness. This is the headline sound level.
• LCeq: the C-weighted average, which gives low frequencies more weight. When LCeq runs well above LAeq, low-frequency sound like HVAC rumble or traffic is present.
• LZeq: the unweighted (Z-weighted) average, which counts sound energy equally at every frequency and serves as a reference.

2. Variability: how much the sound swings between quiet and loud. It's why many people can sleep or focus on a plane, where engine noise is loud but steady, yet struggle to concentrate at a desk next to a break room where a vending machine drops a can every ten minutes. A sensor should report variability with three metrics:

• LA10: the level exceeded 10% of the time, which captures intrusive peaks like conversations, phone calls, and closing doors.
• LA90: the level exceeded 90% of the time, which captures the background noise floor, such as steady ventilation.
• LA10 minus LA90: the gap between the peaks and the background. A small gap means steady sound, while a large gap means a space that keeps swinging between quiet and loud.

3. Frequency: how sound energy is spread from low to high pitch, split into 31 one-third-octave bands. It's why a refrigerator's low hum fades into the background, while a faint, high-pitched whine is hard to tune out. Narrow bands also make tonal noise (a single, distinct pitch) easy to trace, since it shows up as a spike in one band. The bands fall into three general ranges:

• Low (roughly 20 to 250 Hz): HVAC and mechanical rumble, traffic, and building equipment like pumps and fans.
• Mid (roughly 250 Hz to 2 kHz): most of the energy in conversations and phone calls, plus office equipment like printers.
• High (roughly 2 to 20 kHz): the consonant sounds that make speech intelligible, hissing air from vents, and high-pitched electronic or equipment whine.

What Insights Do You Get From Measuring All Four Aspects of IEQ Together?

With sound, air quality, thermal comfort, and light measured together, you can see how the factors affect each other and improve one without making another worse. Here's what that looks like in practice:

• Catch trade-offs between factors. Closing a meeting room door to keep noise out can also limit airflow and let CO2 build up. Seeing sound and CO2 side by side shows when a fix for one factor is creating a problem in another.
• Check that an upgrade worked across the board. After installing acoustic panels, adjusting HVAC, or reconfiguring a floor, you can confirm sound improved without temperature, air quality, or light getting worse.
• Trace a problem to its cause. Opening windows for fresh air can bring street noise in with it. If a room’s sound level rises at the same time its CO2 drops, open windows are the likely cause, so keep them closed during the noisiest hours and use mechanical ventilation to bring in fresh air instead.
• See how spaces are actually used. A meeting room where CO2 and LA10 climb together at the same hours is likely hosting more people or louder activity than planned, which points to a space-planning fix rather than an acoustic one.
• Match spaces to people’s preferences. Some people work best somewhere quiet, cool, and dim, while others prefer a lively, warm, bright space. Seeing all four factors for every room shows what each space actually offers, so you can give people a choice of where to work.
• Respond to complaints with data. When occupants say a room feels uncomfortable, you can look at sound, temperature, humidity, CO2, VOCs, and light together for a full picture of what could be behind it. That way you catch every contributing cause, instead of fixing only the one your data happens to cover.

Why Measure All Four Pillars of IEQ With Kaiterra?

Kaiterra has grown from measuring air quality alone to measuring what we consider the four pillars of IEQ: air quality, thermal comfort, light, and sound. All four affect how people feel, think, and work, so measuring them together on one 4-in-1 platform delivers benefits that standalone solutions can't:

• A complete view of your indoor environment. Sound sits alongside air quality, thermal comfort, and light on the Kaiterra Data Platform, and Kaiterra AI surfaces the specific insights you need with a simple question. Cross-referencing the four reveals connections you'd miss with separate systems, so you can see how they shape occupant comfort, well-being, and productivity, and where to act first.
• Cost-effective coverage. The sound sensor snaps into the Sensedge Go, which already measures the other three pillars, so you pay for one set of monitors instead of a separate system for each one. With up to eight years of battery life, the Sensedge Go keeps maintenance costs low, especially considering the average battery life for IEQ monitors is around one year.
• Simple to manage at any scale. Kaiterra keeps IEQ optimization simple for workplace and real estate leaders who already have plenty of decisions to make and spaces to manage, especially across large, global portfolios. You only deploy one solution, with one platform that gives you the insights you need to act right away. When a specific problem needs a closer look, you can drill down into the detailed data.

Want to learn more about why you should monitor IEQ with Kaiterra? Reach out to our team today to book a demo.