Santa Fe UltraMD33 / Ultra-Aire MD33 (4035900) review

The Santa Fe UltraMD33/Ultra-Aire MD33 part 4035900 is an earlier, wall-integrated dehumidifier with an R-134a refrigerant system. It is useful to identify for an existing owner or a used unit, but it is not the current 4044610 UltraMD33. The older unit needs framing, a drain and electrical rough-in; it is not a portable appliance you can roll between rooms.

This assessment separates the manufacturer’s 2024 brochure for part 4035900 from the exact 2018 Ultra-Aire MD33 TS-927 Rev F installation manual. Santa Fe’s current product materials list the older R-134a sheet among discontinued documents. The exact 4035900 EPA model-number query returned no row, which is not proof of certification status either way.

Check the part number before comparing ratings

The 2024 Santa Fe brochure names model 4035900 on the same page as its MD33 illustration and gives 33 pints per day at 80°F/60% RH. It also lists 17 pints per day at 65°F/60% RH. Those are manufacturer test points, not a promise of the water this appliance will collect in a particular basement or apartment. The same brochure states 4.25 pints per kilowatt-hour and a 2.0 L/kWh Energy Factor at 80°F/60% RH; its 65°F/60% row says 2.7 pints per kilowatt-hour and 1.3 L/kWh. Do not treat Energy Factor as EPA Integrated Energy Factor or convert either figure into a household energy bill.

The naming is easy to confuse: Santa Fe’s current MD33 is part 4044610 and uses R-454B, whereas this older part is 4035900/R-134a. The current manufacturer page reports a different capacity, power and control history. A white wall-front image or the words “UltraMD33” alone do not identify which refrigerant generation is installed. For an existing unit, read the model/part label and use the manual that names that version.

A finished-wall appliance, not a floor-standing unit

The 4035900 manual calls for installation in or on an interior wall and recommends an HVAC professional. The cabinet is 14 3/16 inches wide, 30 inches high and 5 3/4 inches deep; its published weight is 39 pounds. The manual’s cutout is larger—14 1/2 by 30 1/4 inches—and its front diffuser spans roughly 17 1/4 by 33 9/16 inches. These are different measurements: the cabinet, drywall opening and visible face each affect fit. The directions also specify minimum placement clearances from floor, ceiling and corner, and require the cabinet to remain supported by its side mounting flanges rather than pressed against framing. This is a wall alteration and finishing job, not just a small-footprint purchase.

The appliance draws room air into the lower part of its front diffuser and returns dried air through the upper portion. Keep furniture at least six inches from that face, according to the manual, and leave access for the washable filter and controls. The installation guide describes a protected indoor location, not exposure to rain or flooding. Its “up to 1,200 square feet” line is manufacturer sizing guidance, not a load calculation or coverage guarantee.

Gravity drainage is part of the installation

There is no collection bucket or integral pump in this wall unit. The included drain hose is ten feet long with a 3/4-inch inside diameter. The manual says the hose must slope down from the unit to an acceptable drain, recommends a quarter-inch drop per foot, and says the bottom of the cabinet must be at or above the drain height for gravity flow. Local plumbing codes may require a trap. If the drain is higher, the manual says to consider a separate condensate-pump kit; that accessory is not the base model, and the reviewed sources do not establish a maximum lift for it. Do not select this version when an integral lift pump is an essential requirement.

The manual lists both a ten-foot power cord for a permitted plug-in connection and hard-wired installation. It calls for a grounded 120-volt, 60-Hz, 15-amp supply and a visible disconnect for service, and recommends a dedicated GFCI-protected circuit. The installation instructions specifically recommend a qualified professional. Confirm the exact electrical and drainage plan against local code and the actual unit label rather than treating the word “plug-in” as permission to skip safe wall and electrical work.

Controls and routine care

The digital dehumidistat is behind the diffuser, not a phone app. The manual describes an adjustable humidity setpoint from 35% to 99% in one-point increments, with a 55% factory setting; lowering below 35% selects continuous operation. After sampling air, the compressor runs when humidity is above the setpoint and stops once the reading falls three percentage points below it. The unit restarts at its previous setpoint after a power interruption. These are control behaviors from the manual, not independent performance testing. No smartphone, Wi-Fi or connected-control capability is documented for part 4035900.

Its half-inch washable filter sits behind the diffuser. Santa Fe says to check it every two months and clean or replace it as needed; the manual instructs the owner to disconnect power before opening the face for service. The listed operating range is 49–95°F. If the unit is used in a colder area, do not assume it can maintain the warm-condition capacity rating throughout that range.

Who should keep looking

This is a reference for owners verifying a 4035900 or comparing a used installation where permanent in-wall placement and a lower gravity drain are already practical. It is a poor fit for renters, rooms where wall work is unwanted, spaces with no acceptable drain below the unit, people who need casters or a fitted bucket, and any setup that requires a built-in pump, app or HVAC duct connection. For a new installation, compare the current 4044610 UltraMD33 separately: it is a different refrigerant generation, so do not transfer its specifications, warranty, image or purchase listing to 4035900. A portable compressor model may make more sense if mobility and no wall cut-out matter more than a concealed face.