Are Solar Panels Noisy in the Rai
Solar panels are nearly silent—noise comes only from inverters (40-60 dB, like a quiet library). Install them away from bedrooms or use soundproof enclosures to minimize rain-related hums.
Rainy Day Sounds
A heavy downpour with an intensity of 50 mm per hour can generate a broad-frequency sound with peak levels measured between 45 to 55 decibels (dBA) at a distance of 1 meter directly above the roof. For comparison, that's about 10-15 dBA lower than the average rainfall noise on a standard asphalt shingle roof, which typically registers 60-65 dBA under the same conditions.
When panels are installed with a standard 5-6 inch (12-15 cm) air gap for cooling and wiring, that space acts as a shallow resonance chamber. Rainfall hitting the panel at a terminal velocity of approximately 9 meters per second causes the 3-4 mm thick tempered glass to vibrate minutely.
Installations on a corrugated metal roof are 3-4 times more likely to be perceptibly noisier than those on composite shingles or concrete tile, as the metal deck can amplify certain frequencies. Data from a sample of 200 post-installation surveys indicated that only 8% of homeowners on tiled roofs reported ever noticing rain noise, compared to 22% of those with metal roofs.
A rigid, direct-to-truss lag bolt attachment with a minimum penetration depth of 3 inches (7.6 cm) into solid wood provides a 35% reduction in measurable vibration amplitude compared to attachments solely to roof sheathing. The use of 1-2 mm thick rubber or EPDM gaskets or pads between the panel frame and the mounting clamp can further dampen vibration transmission, reducing high-frequency noise modules by as much as 10 dBA.
Factor | High-Noise-Potential Scenario | Low-Noise-Potential Scenario |
Roof Material | Corrugated Metal (<24 gauge) | Concrete Tile or Asphalt Shingle |
Mounting Gap | >8 inches (20 cm) | <4 inches (10 cm) |
Attachment | To sheathing only | Direct to truss/rafter |
Damping | No isolation pads | EPDM pads at all clamps |
Rain Intensity | >50 mm/hour | <10 mm/hour |
A relevant observation from acoustic assessments is noted here:
"In 9 out of 10 cases where homeowners reported significant rain noise, the underlying cause was traced to a loose mounting module—typically a clamp or mid-span bolt torqued below the manufacturer's specification of 15-20 Newton-meters. Retorquing to spec resolved over 80% of these complaints."
Their fan-less designs have a maximum operating sound level of <25 dBA, measured at 0.5 meters, which is below the threshold of hearing in an outdoor environment. Their failure rate is below 0.05% annually, and a faulty unit might produce a louder buzz, but this is a rare maintenance issue, not a weather-related one. The total sound energy from a rooftop solar array in the rain remains orders of magnitude lower than that of the rain event itself, and its probability of becoming an indoor nuisance is statistically low, estimated at under 5% for modern installations following current racking and sealing best practices.
Noise Sources Explained
Surveys of installer callbacks show that less than 5% are for noise issues, and within that subset, the causes follow a clear distribution. Approximately 40% of complaints are traced to thermal expansion and contraction noises from the racking system, which are often mistaken for something breaking. Another 30% stem from wind-induced resonance in the cavity between the panels and the roof. Around 20% are due to loose hardware that was improperly torqued during installation, and the final 10% involve audible hum from power electronics like inverters, though this is typically only heard when standing within 1-2 meters of the equipment on a very quiet day.
A standard 72-cell silicon panel, measuring about 78 by 39 inches, can experience a dimensional change of up to 3 mm along its length during a rapid 40°F temperature swing. When the aluminum frame and the steel mounting clamps expand or contract at different rates—a difference in thermal expansion coefficient of about 13 x 10⁻⁶/°C for aluminum versus 12 x 10⁻⁶/°C for steel—it creates friction at the attachment points.
The probability of hearing these sounds is highest in the first 6-12 months after installation as the system settles, and it peaks during the first 90 minutes after sunrise and at dusk, when temperature change is most rapid, often exceeding 3°F per 10-minute interval. The sound pressure level is usually low, below 30 dBA at 10 feet, but it can be noticeable in an otherwise quiet environment.
A steady wind speed of 15-20 mph flowing over a roof with a 5-inch standoff mount can create vortex shedding behind the panel array. This can excite a low-frequency resonance in the 5-20 Hz range, which is often felt as a sub-audible vibration, but its first harmonic (10-40 Hz) can become audible as a deep hum or drone if it matches the natural frequency of a loose roof-mounted module.
Decibel Levels
In a quiet suburban setting, daytime ambient noise typically ranges from 40 to 50 dBA. A standard, functioning solar panel system in clear, calm weather contributes 0 dBA—it is silent. The noises we examine occur above this background level. Independent acoustic studies, which took over 500 individual measurements across 50 homes for a 30-day continuous period, found that over 95% of recorded solar array noises during normal conditions fell below 35 dBA.
Under a moderate rainfall of 10 mm per hour, the sound of raindrops striking the panel glass registers at approximately 45-50 dBA when measured at a distance of 1 meter (3.3 feet) directly above the roof surface.
For a home with standard R-30 attic insulation and a ⅝-inch thick plywood roof deck, this 50 dBA exterior impact noise is attenuated to about 20-25 dBA inside an adjacent room. This level is equivalent to a whisper and is 15-20 dBA below a quiet room's own ambient noise floor, rendering it inaudible. The key metric is the Signal-to-Noise Ratio (SNR). For a sound to be readily noticeable, it generally needs to be within 5 dBA of the background. Since indoor ambient is around 30-35 dBA, the dampened rain noise fails to meet this threshold.
The sound pressure level might read a relatively low 38-42 dBA outside, but due to its low-frequency nature, it penetrates building materials more effectively, suffering only about 5-10 dBA of attenuation. This can bring the interior level to 30-35 dBA, which is right at the threshold of perceptibility in a quiet house. The duration of this noise is directly tied to wind gusts, with individual events lasting from 3 to 15 seconds.
A central string inverter's cooling fan, when active, produces 42-48 dBA at 1 meter. Microinverters emit a negligible <25 dBA magnetic hum. To illustrate how these levels compare to everyday sounds, consider this scale:
l 10 dBA: Normal human breathing.
l 30 dBA: A quiet bedroom at night.
l 40-45 dBA: A quiet suburban neighborhood or a refrigerator humming from another room.
l 50-55 dBA: Moderate rainfall heard from inside a car. This is the peak level of rain on solar panels measured outside.
l 60-65 dBA: Normal conversation from 3 feet away.
l 70 dBA: A washing machine or shower running.
When a hardware problem exists—like a loose racking clamp vibrating at 120 Hz—the emitted noise can be more pronounced. Measurements from diagnostic calls show a loose module can create a sustained 55-60 dBA tone at the source, which is 15-20 dBA above the normal operational background on a windy day. This outlier is what typically prompts a service call. The takeaway is that the median sound level from a properly installed solar array under all weather conditions is below 40 dBA, and the 99th percentile peak (the loudest 1% of occurrences) rarely exceeds 55 dBA outdoors, which translates to a non-issue indoors for well-constructed homes.
What Affects Noise
Data aggregated from over 300 installer site surveys for noise-related inquiries reveals a clear distribution of primary causes: approximately 60% of issues were traced back to installation quality and module compatibility, about 25% were primarily driven by local environmental conditions, and the remaining 15% stemmed from long-term wear or material degradation. The probability of encountering noticeable noise increases by roughly 35% for systems installed on roofs with a pitch steeper than 6:12 (approximately 26.5 degrees), as the geometry affects wind flow and thermal stress.
Mounting clamps and rail bolts under-torqued by more than 15% below the manufacturer's specification (often 20-25 Newton-meters) can allow for micromovement, increasing the probability of audible creaking or rattling by an estimated 40%. The span distance between roof attachments is equally important. A rail supported every 6 feet is over 3 times more likely to exhibit wind-induced resonance and vibration than one supported every 4 feet.
Different materials expand at different rates. The coefficient of thermal expansion for aluminum panel frames is about 23 x 10⁻⁶/°C, while for steel racking, it's near 12 x 10⁻⁶/°C. This mismatch of 11 x 10⁻⁶/°C means that over a typical daily 30°C (54°F) temperature swing, the materials try to move at different rates, stressing the connection points.
Factor | High Noise Potential Scenario | Low Noise Potential Scenario |
Installation Torque | 15-18 Nm (Below Spec) | 22-25 Nm (To Spec) |
Roof Attachment Span | 6 ft (1.8 m) between supports | 4 ft (1.2 m) or less |
Mounting Type | Ballasted/Non-penetrating on low-slope | Mechanically fastened to rafters |
Age of System | Years 1-2 (settling) or 12+ (wear) | Years 3-10 (stable period) |
Local Wind Pattern | Consistent 10+ mph cross-winds | Sheltered, variable wind under 7 mph |
A 30 mph gust can generate over 2.5 times the dynamic pressure on an array compared to a 20 mph steady wind. The direction is also key; winds hitting the long edge of a panel array create more turbulent airflow and potential for flutter than winds hitting the short edge. The diurnal temperature range is the other major driver. A location with a typical daily swing of 40°F will experience more frequent and louder thermal expansion noises than one with a swing of only 20°F.
Quieter Panel Tips
Data from post-installation service reports indicates that over 80% of noise-related callbacks could have been prevented with upfront attention to a few key details. Investing an additional 1-3% of the total system cost in specific materials and labor practices can lower the probability of future noise issues by an estimated 70-80%.
The first and most critical step is specifying the correct racking system and enforcing strict installation tolerances. Request a rail support spacing of 4 feet (1.2 meters) or less, even if the manufacturer's maximum allowable span is 5 or 6 feet. This reduces the free length of the rail, increasing its natural frequency by approximately 40% and moving it out of the range easily excited by common wind gusts.
During installation, the single most important action is verifying torque. Every single clamp and bolt should be tightened to the manufacturer's specified torque value, which typically falls between 20-25 Newton-meters (15-18 foot-pounds) for most aluminum racking systems. Using a calibrated torque wrench is non-negotiable; a deviation of just 3 Nm from spec can increase the risk of long-term loosening and noise by over 25%. After the initial installation, a follow-up torque check 6-12 months later is highly recommended, as materials settle and compress, potentially causing a 10-15% loss in clamping force.
For the hardware itself, insist on integrated vibration-damping elements. This includes:
l Isolation Pads: Use 2-3 mm thick EPDM or neoprene pads between the panel frame and every mounting clamp. These pads act as a damping layer, absorbing high-frequency vibrations. Quality pads with a Shore A hardness of 50-60 are optimal, reducing structure-borne noise transmission by up to 12 dBA at the source.
l Noise-Reducing Clips: Some manufacturers offer specialized clamps with polymer sleeves or designed geometries that minimize metal-on-metal contact. These can reduce high-frequency "chatter" by an additional 2-4 dBA.
l Sealant Application: Applying a small bead of high-quality, UV-stable sealant (like a silicone or polyurethane) at the interface where the racking foot meets the roof can prevent micro-movements and seal out moisture that could later cause corrosion-related creaking.
For flat or low-slope roofs, a mechanically attached (penetrating) system is generally more acoustically stable over a 20-year period than a ballasted system, which can have a very low but constant rate of shifting.