The Stiebel Eltron CK Premium is the quietest bathroom wall heater we could verify. Stiebel Eltron rates its silent mode, which runs the 120 volt CK 150-1 Premium at 750 watts with a slower fan, at 37 dB(A), and its full 1,500 watts at 48 dB(A). Both figures sit in its technical specifications and in the data table of its installation manual, and no other bathroom wall heater we found has a published figure at both ends of its range.
The only other maker with figures we could rank is Dreo. It lists 28 dB for its 517AS, a plug-in wall heater with an ALCI shock-protection plug, footnoted as tested at the lowest speed setting, and 34 dB for its new 739AS at the lowest heat settings. Those are plain dB from Dreo's own lab, while Stiebel Eltron's are A-weighted, so the lower number does not prove the quieter heater. We rank Stiebel Eltron's heaters against each other, Dreo's against each other, and never one maker against the other.
The established names in hardwired bathroom heat sell on words. Cadet says its Com-Pak wall heaters provide "quiet, efficient warmth", King's submittal for its Pic-A-Watt calls it "whisper quiet", Marley lists a "tangential blower for whisper-quiet operation" on its Berko GFR, and Stelpro's US catalog calls its Oasis bathroom fan heater "ultra-quiet". None of them prints a decibel or sone figure. Of the plug-in heaters, Brightown's "under 36 dB" is an upper limit with no setting and Envi's "0 dB" describes a panel without a fan, so neither is ranked here either.
Our picks are listed above, with full specifications for each.
Why Dreo's 28 dB does not beat Stiebel Eltron's 37 dB(A)
Stiebel Eltron writes every CK figure as dB(A), the A-weighted scale our dBA explainer describes. Dreo prints plain dB on the 517AS and 739AS and does not say whether its lab weighted the reading. Neither maker gives a measuring distance, and the test conditions differ: Stiebel Eltron lists "operating noise" for each heating stage of each model, while Dreo's figures come from "internal laboratory conditions" on the 517AS and the "DREO lab" on the 739AS.
Both Dreo figures describe the bottom of the range, and Dreo's support page for the 739AS family says what happens above it: "The higher the gear setting of the space heater, the louder the noise will be." Dreo publishes nothing for the settings above its lowest. Stiebel Eltron gives the top of its range as well: 48 dB(A) for the CK Plus and Premium at full power, and 49 dB(A) for the single-stage CK Trend.
Within each maker the comparison holds. At full power the three Stiebel Eltron fan heater lines sit within 1 dB(A) of each other, and only the Premium adds a quieter stage. At the bottom of Dreo's range, the 517AS is 6 dB below the 739AS.
What the CK Premium's silent mode gives up for 37 dB(A)
Silent mode is the "Lo" setting in the CK Premium's menu. The manual says the CK 150-1 Premium then heats at 750 watts, half its full output, and the CK 200-2 Premium at 1,000 watts on 240 volts, both with a reduced fan speed. The drop from 48 to 37 dB(A) is 11 dB(A), and the US National Park Service says a 10 dB increase doubles perceived loudness, so by that rule silent mode should sound about half as loud as full power.
The catch is in the same manual: "Do not operate the heater at the base heating stage if the room where it is installed has cooled down significantly." In a bathroom, that means warming the room on the rapid stage and switching to silent mode once it is warm. The timers take care of the first half. A self-learning program "will pre-heat the room so the desired room temperature is achieved at the programmed time not after", and a short program runs comfort heating for 10 to 120 minutes, so the louder warm-up can be over before anyone steps into the shower. Stiebel Eltron's brochure ticks the CK Premium for boosting heat through a timer, "like in a bathroom in the morning".
Open window detection needs knowing about if you air the bathroom after a shower. The manual says that when a window is opened the heater "automatically switches to frost protection mode for one hour", and that you end it by pressing "+" or "OK"; otherwise the room stays unheated for that hour. The manual also notes the feature needs a stable room temperature beforehand to notice the drop. The display's backlight, meanwhile, switches off after 20 seconds without a button press.
ALCI plugs, and the water rules in Dreo's own manuals
Dreo is the only maker here that builds its bathroom pitch around the plug. The 517AS lists an "ALCI Plug (Anti-leakage) Fit for Bathroom Use", the 739AS "ALCI anti-leakage protection" for "added safety for bathroom use", and Dreo's product images give both an IP24 rating. The 739AS manual says what the plug does: it "provides protection against electric shock due to ground fault currents by automatically shutting off the power". It carries TEST and RESET buttons, and Dreo says it should not be used as an on and off switch.
The same manuals set limits. Both say to place the heater as far as possible from bathtubs, showers and sinks, never where it could fall into water, and never to splash it. The 739AS manual adds, in capitals, that although the plug reduces the risk of electric shock, the product "SHOULD NEVER BE USED NEAR WATER." The 517AS manual sets a mounting height of 1 to 4.9 feet above the floor, with more than a foot clear above and below the heater. In a small bathroom, mark that box on the wall before you buy; the spot farthest from the tub, shower and sink is the one Dreo's instructions point to.
Dreo also sells the 517S, the same heater with the same 28 dB, for about $20 less, and its page says it brings heat to bathrooms as well. For a bathroom we would pay the difference, because the ALCI plug is the feature Dreo itself labels fit for bathroom use.
Plug-in or hardwired, and what the installation sections ask
Each 120 volt Stiebel Eltron heater on this page can plug into a grounded outlet or be hardwired. The CK 150-1 Premium comes with a 39 inch cord, the CK 150-1 Trend with a 47 inch cord and the CON 100-1 Premium with a 59 inch cord. The 240 volt CK 200-2 models connect at a junction box on the back, so they are hardwired. All three Stiebel Eltron manuals reserve the installation chapter for qualified contractors, and the CK Plus and Premium and CON manuals add that a permanent connection needs an isolator that disconnects all poles with at least 1/8 inch (3 mm) of contact separation.
For the plug-in versions the manuals are blunt: no extension cord, no power strip on the Trend and CON, and "Always unplug heater when not in use!" They also say never to mount the heater directly below a wall socket, and the Trend manual asks for at least 4 inches (10 cm) between the two. In the United States, both CK manuals want at least 4 inches between the floor and the bottom of the heater and recommend 6 to 8. Their list of things never to place on or near the heater starts with laundry, which in a bathroom means the towels.
Only the Trend manual has rules written for the tub. It says to install the heater "in such a way that control equipment cannot be touched by a person in the bath or shower", and to observe the safety zone given on the heater's type plate. The CK Plus and Premium manual names bathrooms among its uses but does not repeat those lines.
Dreo's heaters plug in only, and the 739AS manual says it is "intended for 120V outlets only"; plugged into 240 volts by mistake, it cuts the heating and shows a "UH" code. The 739AS cord is 70.8 inches and the 517AS cord 5.9 feet, which decides how far from the outlet each can hang.
A convection heater has nothing that spins, which is why Stiebel Eltron's brochure lists the operating noise of its CON and CNS heaters as "Silent" and Envi says its LE5012P panel "operates at 0 dB". Both are descriptions of a heater without a fan, not readings from a meter.
What a bathroom gives up is speed. Stiebel Eltron's own selection table ticks only its fan heaters for "the quickest way to heat a space", and Envi's manual warns that its 500 watt heater may need "several hours" to bring a room to its settled temperature. A bathroom used for twenty minutes in the morning suits a fan heater on a timer. One kept warm all day, or an en suite beside a bedroom where any fan would be heard at night, suits the fanless CON 100-1 Premium, which keeps the CK Premium's booster timer of up to 120 minutes.
Envi says its plug-in panel is fine in a bathroom "as long as the heater is installed outside the splash zone and local electrical codes are followed", and its manual asks for the bottom of the panel to sit 6 to 8 inches above the floor.
Sizing a bathroom heater from the makers' room estimates
Bathrooms are small, so the sizing question is usually which heater is more than you need. Stiebel Eltron estimates 150 square feet for its CK 150-1 heaters, 200 for the CK 200-2 heaters and 100 for the 1,000 watt CON 100-1 Premium, the last "based on average insulation". Envi rates its 500 watt panel for 130 to 150 square feet. Dreo gives no room size for the 517AS or 739AS, only 1,500 watts with 900 and 1,300 watt settings below it.
The amps matter on a bathroom circuit that already serves a hair dryer. The 120 volt CK heaters draw 12.5 amps at full power, and Stiebel Eltron recommends a 15 amp breaker for each; the CK Premium's 750 watt silent mode uses half the power of its full stage. The CON 100-1 Premium draws 8.3 amps, and Envi's panel 4.17.
Ceiling fan-heaters carry sones instead
If the bathroom also needs its steam cleared, the other route is a ceiling exhaust fan with a heater built in, and those are rated in sones for the fan. Panasonic's submittal for the WhisperWarm DC FV-0511VH1, which has a 1,600 watt PTC heater, rates the fan, as certified by the Home Ventilating Institute, at under 0.3 sone at 50 and 80 CFM and no more than 0.7 sone at 110 CFM, all at 0.1 inch of static pressure. The same sheet requires a minimum 20 amp dedicated circuit and says the fan-heater "is not intended for installation over a tub/shower enclosure". Sones are their own loudness scale, set out in sones vs decibels, and they describe the exhaust fan's airflow test, so we never line them up against a wall heater's dB or dB(A). A ceiling fan-heater is chosen as a fan first, so its sones belong with the quietest bathroom exhaust fans rather than on this page.
How we chose
We looked for wall heaters sold in the US for bathrooms, hardwired or plug-in, and read each maker's product pages, technical specifications, brochures and installation manuals between October 10 and 13, 2026. Stiebel Eltron and Dreo were the only makers with decibel figures tied to a setting or stage. Cadet, King, Marley's Berko and Fahrenheat lines, Stelpro's US catalog and Heat Storm's product descriptions gave words only. Broan-NuTone's website refused our requests, and the copy of its specification sheet for the 170, 174 and 178 fan-forced wall heaters that we could read, hosted by a distributor, prints no sone or decibel figure. Convectair's Soprano bathroom fan heater appears only on its Canadian site, so it has no place in a US guide.
We ranked Stiebel Eltron's dB(A) figures against each other and Dreo's dB figures against each other, and set fanless heaters apart because their makers publish words, not numbers. Dreo's 719S belongs to the same family as the 739AS but is sold for bedrooms and garages without an ALCI plug, so it sits with the heaters we considered rather than among the picks. Dreo also sells ALCI versions of two floor-standing heaters, the Ceramic Heater 314 and the Solaris Slim H3, which fall outside a wall heater guide; Dreo's other heaters are on our Dreo space heater decibels page. Dreo's prices are those on dreo.com on October 10, 2026; Stiebel Eltron publishes no prices, so its cards show none.
We did not measure any of these heaters ourselves; every figure on this page is Stiebel Eltron's or Dreo's own.
