Whole-home capacity and installation

Santa Fe UltraMD33 vs Ultra70: in-wall room control or ducted distribution

Santa Fe’s UltraMD33 and Ultra70 share the Ultra name, but they solve different installation problems. The MD33 is part 4044610, a slim in-wall room unit; the Ultra70 is part 4044100, a compact ducted dehumidifier. Compare the location, duct and drain plan first, then compare the capacity ratings.

The same name also appears on an earlier Ultra-Aire MD33, part 4035900 with R-134a. Santa Fe’s 2024 brochure rates that separate configuration at 33 pints/day at 80°F/60% RH and 17 at 65°F/60% RH; its exact manual is TS-927 Rev F. The manufacturer lists the older R-134a documents as discontinued. Keep it separate from current 4044610/R-454B, which the table below describes. See the 4035900 reference assessment if identifying an existing unit; do not transfer current-part specifications or imagery to it.

For installation and service details, use the manufacturer’s TS-2091 instructions for current MD33 part 4044610 and current Ultra70 TS-2082 Rev C instructions for part 4044100. Verify the part number and the supplied instructions before planning a wall opening or duct layout.

Start with the installation category

The UltraMD33 recirculates air through a wall diffuser and is independent of central HVAC ducting. It suits a room, apartment or zone where an interior wall can be opened and a gravity drain can run down from the cabinet. Its 14.19-by-30-by-5.75-inch body does not include the wider front plate shown on the manufacturer drawing, so measure the rough opening and finished face. A surface mount, a through-wall 2×4 installation or an unconditioned wall may need a separate finish or rear-panel kit.

The Ultra70 is not in-wall. It needs an eight-inch return and eight-inch supply duct layout, room for filter and service access, and a condensate route. Its supply panel can be rotated for horizontal or vertical discharge. The manual recommends eight-inch ducting for shorter runs and larger duct for longer runs; it warns against excessive static pressure. This is more appropriate when air needs to be distributed through a house or designed zone than when a single apartment room needs a wall-integrated appliance.

Compare ratings at the same conditions

These are controlled manufacturer ratings, not guaranteed household extraction. The area claims—up to 1,200 square feet for MD33 and up to 1,800 for Ultra70—are sizing guidance rather than load calculations. Compare the condition on each number; do not compare one model’s warm test point with the other’s cooler point as if they were equivalent.

Drain, controls and upkeep are part of ownership

Neither base configuration has a bucket or an integral pump. Both can use a lower gravity drain, but their manuals call for different details: MD33 has a supplied wall-routed hose and downward slope; Ultra70 uses a trapped PVC drain with a specified fall. Separate pump accessories are possible, but the Ultra70 manual does not state a maximum lift, and an accessory should not be counted as a built-in pump. Confirm the exact drain fitting and overflow protection with the installer.

MD33’s digital set point is behind the diffuser, and its washable filter should be checked every two months. Ultra70 has a built-in dehumidistat plus wired low-voltage controller options; its included MERV-13 filter is checked every three to six months. A remote controller, outside-air ventilation schedule and duct layout should be planned together for Ultra70. Neither model’s filter specification is evidence of medical or mold-remediation performance.

Which should you shortlist?

Shortlist the MD33 if a wall opening, clear diffuser face and gravity path suit a self-contained room or apartment. Choose the Ultra70 only when ductwork, a low-voltage control arrangement and a drain are available, and when house-wide distribution or optional ventilation matters. If the space cannot accept fixed installation, compare portable models instead. Check the exact part number, supplied manual, ratings, drain route, electrical requirements and warranty terms before purchasing; the matching capacity label alone cannot tell you whether the installation will work.