Rheem ProTerra Hybrid Noise Levels and Acoustical Treatments

A homeowner who works as a noise consultant tested his own Rheem ProTerra heat pump water heater (a unit that pulls heat from the surrounding air to heat water, rather than using a standard electric element) after installing it in his garage instead of the closet he'd originally planned. Standing three feet from the fan, he measured 50 decibels (dBA) — noticeable, but not harsh, and roughly on par with a running white noise machine. He noted that most people find 35-40 dBA comfortable for a bedroom, so anyone installing one of these units near a sleeping area should expect some sound.

He outlined, though didn't fully build, a plan for quieting the unit in a tighter space like a closet: choosing Rheem's quieter fan option, adding rubber isolation pads or a "vibration kit" to cut down vibration, running insulated ductwork to move air in and out of the room, and lining the compressor cabinet with mass-loaded vinyl and sound-absorbing material to block noise at the source. In his garage he only added simple foam pipe-insulation absorption inside the cabinet, calling it cheap and easy, though he noted it does little for the low-frequency hum from the compressor itself.

His main takeaway for anyone installing this type of water heater near living space: fan noise responds well to sound-absorbing add-ons, but the deeper compressor tone is harder to quiet and depends more on how well-sealed and solidly built the surrounding room is — tight air sealing, dense wall materials, and solid-core doors with rubber gaskets make the biggest difference.