AprilAire's lowest is the E080 at 45 dBA ducted. AlorAir's is the Sentinel WHD 100, at 44 dB minimum to 55 maximum. The two numbers share no stated basis.
| Maker and label | Models, lowest first |
|---|
| AprilAire, "dBA ducted" | E080 45, E130 50, E070 53, E100 55 |
| AlorAir, minimum to maximum at 0 Pa | WHD 100 44 to 55, WHD 120 48 to 62, WHD 200 53 to 65 |
| Santa Fe, "Average Sound Level" | Ultra98 47.5, Ultra70 55.3 |
Of the two Santa Fe averages the Ultra98's is lower, but we could not confirm the model is still current. The Ultra70 is the Santa Fe pick, and the Ultra98 sits under Also considered.
Three brands, three kinds of number
A 45 from AprilAire cannot be set against a 47.5 from Santa Fe or a 44 from AlorAir. Each prints a different kind of figure, and none gives the distance from the cabinet.
AprilAire prints one figure per model and labels it "ducted". AlorAir prints a minimum and a maximum at "0 Pa static pressure", meaning no duct resistance at all. Santa Fe's product pages each carry an "Average Sound Level", while its data sheets and manuals give none. With no distance, a reading taken one meter away and another taken three meters away could describe the same machine, which is why the E080's 45 is never placed above the Ultra98's 47.5 here.
The same problem is laid out in our explainer on comparing ratings across brands.
How quiet is the AlorAir WHD 100 in low noise mode?
AlorAir does not say. Its documents give the WHD 100 a minimum of 44 dB and a maximum of 55 dB under a table titled "Noise in Constant Air Volume and Low Noise Mode", with no word on which mode produced which figure.
The clues sit nearby. The same summary table lists the blower at 390 m³/h in "Low Noise Mode" and 525 m³/h at "0'' WG" for the WHD 100, and the manual outline describes a fan speed button with "low and high settings". Read together, the 44 is most likely the low fan figure. The product page settles on the top number, "Sound Pressure Level 55dBA".
Across the line both ends climb. The minimum rises from 44 on the WHD 100 to 48, 52 and 53 on the WHD 120, 150 and 200, and the maximum from 55 to 62, 64 and 65, while airflow grows to 650 m³/h for the WHD 150 and 700 for the WHD 200.
Two paths into the rooms
Blower noise rides the duct to a grille. Vibration passes from the cabinet or its collars into rigid ductwork and framing, and every manual here treats that second path as an install problem.
Flex duct at the collars
AprilAire's installation sheet for the E080 and E100 wants 12 inches or more of flex duct on both the inlet and the outlet, "to prevent vibration noise transmission". Santa Fe asks for flexible ducting on every Ultra70 connection too, to limit what passes into "rigid ductwork in the structure". Insulated flex duct, or other vibration isolating material, fitted at the Ultra70's outlet "will reduce air noise from the blower".
Return to return, or return to supply
AprilAire's manual shows four ways to tie into the house system.
Pulling from the return and discharging into the return needs wiring so the HVAC blower runs with the unit; otherwise, AprilAire warns, dried air can short-circuit straight back to the inlet. Discharging into the supply side means "the HVAC blower does not need to be running". AprilAire still recommends the wiring there, since running the fan "ensures the warm dry air is mixed with room air". Where codes forbid ducting to the return, dedicated registers for the inlet and the discharge are allowed.
A backdraft damper
A backdraft damper comes with the E080 and E130 outlets. For the Ultra70, Santa Fe says one is "required in the supply duct", to stop supply air flowing back through the unit when it is off.
Where a whole-house unit stays quiet
The quiet spot is one where the cabinet rests on isolation rather than on the structure, away from bedroom floors, with a control mounted upstairs so nobody has to go down to it.
Santa Fe's Ultra70 instructions warn that a unit set on structural building members "without vibration absorbers" may make "unwanted noise". Hanging with a hang kit is allowed, hanging from the cabinet is not. AprilAire's E080 and E100 manual covers the attic case: "For attic installations, suspending the dehumidifier is recommended to reduce noise transference." For a unit in a crawl space or attic it suggests a wall control such as the Model 76 "mounted in the living space and wired to the dehumidifier".
Both makers want a condensate pan under any unit above a finished room. For basements that already hold a furnace and water heater, our page on a quiet basement covers the rest of the room.
What size whole-house dehumidifier keeps run time down?
One sized for the house, since it runs fewer hours. Makers size these by floor area, so compare that first, then capacity at the cooler 73°F condition rather than only at 80°F.
| Model | Maker's sizing |
|---|
| Santa Fe Ultra70 | Up to 1,800 sq. ft. |
| AlorAir WHD 100 and Santa Fe Ultra98 | Up to 2,300 sq. ft. |
| AlorAir WHD 120 | Up to 3,000 sq. ft. |
| AlorAir WHD 200 | Up to 4,500 sq. ft. |
AprilAire's sheets give capacity instead of floor area. At 73°F and 60% humidity the E070 removes 53 pints a day, the E080 65 and the E130 105, against a DOE figure of 70 for AlorAir's WHD 100.
Bigger is not always louder. AprilAire's 130-pint E130 lists 50 dBA ducted against 55 for the 100-pint E100, though AlorAir's range climbs with every size step.
AprilAire prints two figures for its ventilating E100V, and Santa Fe's newer Ultra V100 page prints none.
The sheet for the E100V and 8190FF plenum lists 52.8 dBA ducted with the fan only and 55.0 dBA with compressor and fan. The fan-only number is the one that applies while the unit moves air without drying it. Santa Fe credits the Ultra V100's R2 cabinet insulation with "quieter operation" and leaves the sound level out of its specification table, while the older Ultra98 and Ultra70, which also take fresh air through a duct, carry an average figure.
Do Honeywell and Ultra-Aire whole-house units print decibels?
Honeywell Home's DR90A3000 does not. Ultra-Aire is now a Santa Fe name: the Ultra98 page reads "(Formerly Ultra-Aire 98H)", and its 47.5 dBA is Santa Fe's figure.
Resideo's specification data for the DR90 says "Reduced noise during operation" and stops there, though its installation guide still asks for flex duct at the collars "to reduce vibration noise". Therma-Stor's site calls the company "A Family of Brands", shows the Santa Fe logo among them and sends product questions to the Santa Fe website. No whole-house unit sold under the Therma-Stor name turned up with a figure.
