How loud is a data center?

Decibels (dB) measure loudness on a logarithmic scale: a 10 dB increase sounds roughly twice as loud. Everyday benchmarks: a whisper is ~30 dB, a refrigerator ~50 dB, normal conversation ~60 dB, a lawnmower ~90 dB.²⁹ Outdoors, sound from a compact source fades about 6 dB every time you double your distance from it.³⁰

One wrinkle matters for data centers: standard measurements use “A-weighting” (dBA), which mimics human hearing and under-counts low-frequency sound. Cooling fans and transformers produce exactly that kind of low rumble and 120 Hz hum — which travels farther and penetrates walls better than higher-pitched sound. That’s why a facility can pass a dBA limit and still produce an audible indoor hum that neighbors find maddening.²⁷ Some Virginia counties now add a separate dBC (low-frequency) limit to close that gap.⁴⁵

Sources: acoustic consulting measurements,²⁷ EESI,²⁸JLARC’s Virginia study,¹⁴ Mississippi Today (xAI),⁴³ and crypto-mining fan specs.³⁵

Two big takeaways. First, the loudest routine event at a conventional data center is generator testing — typically monthly, 30 minutes to 2 hours per generator, at 90–105 dB up close — which is why permits usually restrict testing to daytime hours.²⁷ (Virginia air permits cap generators at roughly 500 hours per year, total, including emergencies.⁴⁷⁷⁶) Second, the continuoussound — the “hum” — comes from cooling. Air-cooled facilities with walls of fans are the loudest class; liquid-cooled halls run 40–55 dB versus 70–85 dB for air-cooled equivalents.²⁷

A practical example from acoustic consultants: equipment producing 70 dB at 50 feet attenuates to roughly 60 dB at 200 feet, 50 dB at 800 feet, and 40 dB at a half mile over flat, open ground.²⁷ Terrain changes this in both directions: hills and barriers block sound, while nighttime temperature inversions — common in valleys like ours — can carry low-frequency sound farther than the simple math suggests.²⁷ Distance is the cheapest, most reliable protection: the proposed Pikeville site is inside an existing industrial park, and how far the nearest homes are from the cooling equipment will matter more than almost anything else. See the map page for the actual geography — the park sits on a plateau several hundred feet above the nearest valley homes, roughly a mile away.

Virginia (the largest data center market on Earth): JLARC, the legislature’s research agency, found that most Virginia data centers generate no noise complaints, but about a third sit within 200 feet of residentially zoned land, and at facilities that did draw complaints, measured noise typically ran 40–59 dB — not hearing-damaging, but a constant presence that some residents said affected their well-being.¹⁴ In the best-documented retrofit, Amazon replaced all 424 rooftop exhaust fans at a Manassas-area complex after neighbors measured up to 65 dB at night; the fix cut the noise about 10 dB, to ~50 dB, confirmed by both sides.³⁴Complaints continue elsewhere — in 2026 a TV crew’s phone app read 90 dB near a Loudoun facility neighbors compared to “a helicopter hovering all day and night” (phone apps aren’t calibrated instruments, but the complaint record is real).⁴²

Granbury, Texas (crypto mine — the worst case): a Bitcoin mine with ~60,000 air-cooled machines was built less than 100 yards from a mobile-home park.³⁵ A county constable recorded readings near 85 dB and issued 37 citations; a county-funded study later measured ~60 dB near the facility and 35–53 dB within a mile — the dispute over measurements is itself part of the story.³⁵Residents reported migraines, vertigo, and tinnitus to TIME’s investigators;³⁷ a jury acquitted the site manager of criminal noise charges,³⁸ and a civil nuisance lawsuit filed by Earthjustice is still pending.³⁶ The operator built a 2,000-foot sound wall and converted two-thirds of the machines to immersion cooling; residents say it helped little.³⁵Similar crypto-mine noise fights played out in Murphy, NC (55–85 dB in a neighbor’s yard)⁴¹ and Adel, GA.⁴⁶

Closest to home — two Eastern Kentucky cases: Pike County’s own Blockware Bitcoin facility in Belfry — an air-cooled crypto mine, the loudest facility class — has operated since 2022 with no noise complaint, lawsuit, or negative coverage anywhere in the public record after four years; it occupies a former coal processing site rather than sitting against homes.¹²⁷¹⁸In Wolfe County, by contrast, neighbors of a crypto facility that began operating in 2023 next to a substation reported relentless 24/7 fan noise and sleep disruption; a promised barrier wall became “sound blankets” residents called cosmetic, and the county declined to pass a noise ordinance.¹³⁰ Same state, same technology — the difference was siting and follow-through.

Chandler, Arizona (the policy model):after years of hum complaints traced to chiller fans, the operator installed sound attenuation, and the city passed the nation’s first data-center noise ordinance: a pre-construction baseline sound study, a requirement that operating noise not exceed that baseline, five years of annual verification studies, restricted generator-testing windows with neighbor notification, and an on-site community liaison.⁴⁰³⁹

The World Health Organization recommends nighttime outdoor noise below 40 dB (long-term average) to protect sleep, with 55 dB as an interim target,³¹ and its 2018 guidelines recommend keeping average road-noise exposure below 53 dB.³²The EPA’s longstanding guidance puts the protective outdoor day-night level at 55 dB.³³ Typical local ordinances allow 55–65 dBA at a residential property line by day and 45–55 dBA at night.²⁷

• Acoustic shrouds and louvers on cooling equipment: 5–15 dB reduction at the source.²⁷
• Generator silencers: 10–20 dB; full sound-attenuated enclosures up to 40 dB.²⁷
• Sound walls and earth berms: 10–20 dB, but only where they block the line of sight — low-frequency sound bends over barriers (see Granbury).²⁷³⁵
• Fan redesign at the source works best: Amazon’s Manassas retrofit measurably delivered ~10 dB.³⁴
• Liquid/immersion cooling: converts a 70–85 dB air-cooled hall into a 40–55 dB one.²⁷
• Setbacks beat everything: moving equipment from 200 ft to 1,600 ft from homes cuts ~18 dB by physics alone.²⁷³⁰