Efficient Hot Water With Less Noise
Seeking a quiet heat pump water heater? Noise may be part of the bargain.
I’m considering installing a heat-pump water heater (HPWH) to replace my electric-resistance water tank. Unfortunately, I see regular online reviews of common models complaining about premature failures and noise from the heat pump’s refrigeration unit. Are there quiet, reliable models out there? I plan to put the water heater in my conditioned crawlspace, which measures about 1200 sq. ft.
— Eli; Via the GBA forum
Jake Staub, Chief Technical Officer at Ripcord Engineering, Replies
The short answer is no. “Packaged” HPWHs (those with compressors above the tank) that are installed inside the conditioned envelope are perceived as “loud” by most people.
My company, Ripcord, has found that approximately 25 dBA is a tolerable level of noise for most people. The “A” in dBA signifies a weighted decibel, as perceived by humans. According to manufacturer data, the least “loud” packaged HPWH is a 42-dBA unit by LG. Most others operate at around 60 dBA.
So for a “quiet” installation, acoustic isolation for the water heater must compensate for unit noise. Simply put, you need to deliberately separate a packaged HPWH from the living area. Make sure the acoustic separation complies with code and follows manufacturer’s instructions to ensure safety, proper operation, and warranty coverage.
To reduce the heat-pump water heater noise level in crawlspaces that connect to living spaces, install a weatherstripped door and seal air leaks between the crawlspace and living space. Then follow code requirements for unvented crawlspaces.
For packaged HPWHs in mechanical closets, follow manufacturer instructions for ducted installations. A tight-sealing door and a sufficiently air-sealed mechanical space will reduce sound transmission. Silencers, produced by manufacturers like Zehnder and Fantech, are recommended for intake and exhaust ductwork.
Another quiet way to make hot water is with a split HPWH like the SanCO2, which has a separate compressor installed outdoors. Split HPWHs cost more than packaged HPWHs but can be cost-effective compared to installing a packaged HPWH with a complex plan for acoustic separation.
— Jake Staub; Chief Technical Officer at Ripcord Engineering
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View Comments
There is always this consternation around the topic of noise from HPHW units. At their heart, HPHW units are refrigerators running in reverse. Refrigerators make noise and they are located in the kitchen (maybe the most lived in room in a dwelling), yet rarely is there any concern about refrigerator noise. Are HPHW units really that much louder?
I read this as a two part question but (somewhat understandably) only saw one answer. The question was "are their quiet, reliable models out there?".
Lots of frightening stories on the A.O. Smiths in reviews at Lowes.com; ditto for the Rheems at HomeDepot.com.
Okay, not having a lot of luck editing or deleting my prematurely-launched comment.
I read this as a two part question but (somewhat understandably) only saw one answer. The question was "are there quiet, reliable models out there?". Only the noise was addressed in the answer.
Lots of frightening stories on the A.O. Smiths in reviews at Lowes.com; ditto for the Rheems at HomeDepot.com. Not surprisingly, the retailer's customer service plays a significant part in a lot of the stories.
SANCO2s are really expensive!
Stiebel Eltrons look interesting and I can get one through Hajoca. Service or parts? Hmmmm.
I've read a few too many negative reviews of LG and Samsung, e.g., washers/dryers. Makes me a little leary (okay, completely leary) of an LG HPWH.
Anybody have any good news to share about a reliable HPWH? They sure make a lot of sense on paper.
Ref SANCO2, yes, expensive. BUT they use CO2 as a refrigerant with a GWP of one (1), far better than the (non-flammable) compounds like hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs).
See https://www.webstaurantstore.com/article/474/refrigerant-types.html
miles,
The problem with editing has been around for quite a while. Hopefully, AIM, the new owner of the Taunton brand, will fix it soon.
https://www.aimmedia.com/