Category Archives: noise

Noise and sound level measurement

The main source of noise on heat pumps are the fans

Avoid noise from heatpump outdoor

Avoid noise from heatpump outdoor

Helpful guide for private builders

The Bavarian State Office for the Environment (LfU) has published a guide to dealing with noise problems caused by the installation of air-source heat pumps in private houses. In this connection the authority examined individual components of a heat pump regarding noise. Fans are not the only source of noise, but they are responsible for ninety percent of noise problems. During the preparation of the guide, it also came to light that there are considerable differences in the quality of individual products in terms of noise. After all, if all components of an air-source heat pump are optimized in terms of noise, the sound power level should be no more than 50 dB(A). In fact, however, the sound level of equipment on the market can be 70 dB(A) and above.
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With the headphones on humming search

Mr. Zenkel on humming search

Mr. Zenkel on humming search

Customers are calling building-biologist Oliver Zenkel whenever they hear very quiet sounds. The hum is imperceptible with normal hearing. Particularly disturbing is the monotonous and recurring frequency. The person concerned enters a feeling of helplessness. Mr. Zenkel has adjusted to the soft tones and plugged a headset to the sound level meter as technical reinforcement. How the search for the hum can succeed, describe the following examples.
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Highway bridge transmits humming

the highway bridge is the cause of the humming

the highway bridge is the cause of the humming

For months Roland Wernstein (Germany) examines an annoying buzzing sound in his neighborhood: the heating system, bass from the neighborhood, truck engines, vibrations caused by rail or air traffic were suspected, but were rejected. The end of March 2016 he took time for the facts check: the humming was heard only at night and when the wind from the southwest, recalled a distant diesel engine running and had short, miscellaneous long interruptions.
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The inner ear is slowly recovering from low frequency sound

low-frequency-soundThe negative effect of infrasound on human health is controversial in the permitting of industrial installations. The scientific evidence is thin so far. Researchers at the Ludwig-Maximilian-University Munich (LMU) could now prove that the inner ear needs a relatively long time to recover from exposure to low-frequency sound. “The recovery time is longer than the duration of the load,” says researcher Dr. Drexl of the Department of Neurobiology at the LMU. Continue reading