Are Heat Pumps Noisy?

Heat pump noise is measured in decibels, or dB. The scale is logarithmic, meaning every 10 dB increase sounds roughly twice as loud. For reference, a whisper is about 30 dB, a refrigerator hum is 40 dB, normal conversation is 60 dB, and a vacuum cleaner is 70 dB. The outdoor compressor unit makes most of the noise. Indoor air handlers are much quieter, typically operating between 19 and 35 dB. That is quieter than a library. Manufacturers publish sound ratings for both the indoor and outdoor units. Look for these numbers when comparing models.

Mitsubishi's Hyper Heat outdoor units operate between 47 and 58 dB depending on the model and speed. The 47 dB models are quieter than a refrigerator. At full speed in extreme cold, they reach 58 dB, which is about the level of normal conversation. Daikin Aurora outdoor units range from 44 to 55 dB. Daikin is generally considered the quietest of the major brands. At minimum speed, the unit is practically silent from 10 feet away. Fujitsu XLTH outdoor units range from 45 to 56 dB. Carrier's Infinity heat pump ranges from 54 to 68 dB. American brands tend to be slightly louder than their Japanese competitors, especially under heavy load. The indoor air handlers for all these brands sit between 19 and 30 dB at low speed.

A modern heat pump installed correctly should not be noticeable from inside your home. The indoor unit produces a soft airflow sound similar to a ceiling fan on low. The outdoor unit may be audible if you are standing next to it, but from 15 to 20 feet away, it blends into background noise. Placement matters. Do not install the outdoor unit directly outside a bedroom window. A few feet of distance or a fence dramatically reduces perceived noise. Vibration isolation pads under the outdoor unit prevent sound from transferring through the ground into your home. Most installers include these by default. If your neighbor's unit is 10 feet from your property line, you will likely not hear it at all at a distance of 30 feet or more. Modern heat pumps are simply not the noisy machines of the past.