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Ultra-Aire SD12

The First Split Whole House Ventilating Dehumidifier With No Added Sensible Heat Load — Specifically Designed for Hot, Humid Climates

Dehumidifier and Condensing Unit Specifications

Part Number: 4033175
Shipped Together on Pallet
Pallet Dimensions: 42″W x 32″H x 42″L
Pallet Weight: 220 lbs.

Dehumidifier Specifications

Part Number: 4033175
Blower: 406 CFM @ 0.0″ WG
374 CFM @ 0.2″ WG
348 CFM @ 0.4″ WG
Power: 160 Watts @ 80°F and 60% RH
Supply Voltage: 115 VAC – 1 Phase – 60 Hz
Current Draw: 1.4 Amps
Energy Factor: 3.1 L/kWh
Operating Range: 56°F Min and 95°F Max
Sized For: Up to 4,000 Sq. Ft. – Typical
Minimum Performance at 80°F and 60% RH
Water Removal:
Sensible Cooling:
184 Pints/Day
4,300 BTUs/Hour
6.6 Pints/kWh
Duct Connections: 6″ Round Inlet
10″ Round Inlet
10″ Oval Outlet
Air Filter: Standard MERV 11
Standard Pleat
Size: 16″ x 20″ x 2″
Efficiency: 65% ASHRAE
Dust Spot
Optional MERV 14
Embossed Pleat
Size: 20″ x 24″ x 4″
Efficiency: 95% ASHRAE
Dust Spot
Power Cord: 9′, 115 VAC, Ground
Drain Connection: ¾″ Threaded Female NPT
Drain Hose:
Dimensions: 20.25″W x 21.75″H x 41.5″L
Weight: 110 lbs.

Condensing Unit Specifications

Part Number: 4033192
Power: 1,080 Watts @ 80°F and 60% RH
Supply Voltage: 115 VAC – 1 Phase – 60 Hz
Current Draw: 9.7 Amps
Min. Circuit Ampacity: 20 Amps
Max. Fuse/Breaker Size: 20 Amps
Refrigerant: R410a
Operating Range: 40°F Min, 115°F Max
Power Cord: Hard Wired
Dimensions: 10″W x 25.5″H x 33″L
Weight: 75 lbs.

Attic Installation

Ultra-Aire SD12 Attic Installation (Alternate Install Options)


  1. The indoor air return should come from an open area on the first floor or main level of the home / building.
  2. The Ultra-Aire supply can be ducted into the forced air system downstream of the air conditioning coil. The duct connection should be perpendicular to the air flow. You may also run an independent supply directly from the dehumidifier into a large open room. Depending on the application, multiple returns and or supplies may be needed.
  3. The optional six inch fresh air intake should be located at least six feet away from any exhaust ports, such as, dryer, range hood, or combustion device exhaust. Intake location should be consistent with local codes.
  4. A section of flex duct or vibration absorbing duct should be located between the connections of the Ultra-Aire ductwork and the forced air system ductwork. (When ducting into the forced air systems)
  5. A back draft damper should be installed when ducting into the forced air system. This prevents counter-flow of the A/C supply air through the UA SD12. A back draft damper is not needed when ducted independently.
  6. If placed over a finished area, a secondary drip pan is recommended
  7. Place condensing unit outside of the structure on a level pad (or bracket). If placed on a roof, vibration dampening material may be used.
  8. Install a dedicated 120VAC branch circuit for the condensing unit.
  9. Supply a line set suitable for use with R410A refrigerant to connect the indoor unit to the outdoor unit. The maximum allowable length of the line set is 50 feet. Braze the lines to the dehumidifier and the condensing unit.

Please Note: Therma-Stor does not recommend drawing air from the return ducting system and discharging into the supply, because it could reduce the capacity and may cause counterflow through the air conditioning unit. Preferred installation is to draw air from a separate return duct located in the central part of the home. Duct the outlet air into the supply duct for distribution throughout the home. A backdraft damper prevents air from the supply duct from being pushed backward through the Ultra-Aire SD12 when central (A/C) fan is on and the Ultra-Aire fan is off.

The revolutionary new Ultra-Aire SD12 transforms how residential humidity issues are solved in hot humid climates. By removing over 180 pints of water per day and providing sensible cooling to the living space — all while adding no sensible heat load — the SD12 is the most efficient, cost-effective way to control humidity, enhance comfort, and boost indoor air quality.

The Ultra-Aire SD12 is the total solution for your customers in hot, humid climates; it provides all the benefits of supplemental whole house dehumidification with none of the drawbacks: heat load, noise, and vibration.

The Ultra-Aire SD12 features the ability to supply truly dehumidified fresh air ventilation for improved indoor air quality and achieving a slight positive pressure to the house. The ventilation function is controlled separately from the dehumidification and filtration, allowing ventilation to be customized for any application.
The Ultra-Aire SD12 includes air filtration to improve indoor air quality. A MERV 11 media filter is standard. An optional external MERV 14 filter box and deep pleated 95% media filter is available for optimum air filtration and to reduce potentially harmful airborne particles.

See the Ultra-Aire SD12 in Action


The Inside Story On Humidity & Fresh Air

Clear The Air
With Teddy Bear


See more videos on our Youtube Channel.


Ask This Old House’s Richard Trethewey helps New Orleans homeowners solve high humidity issues in their 1940s-era raised basement home.


Did You Know?

Ultra-Aire dehumidifiers provide superior indoor air quality through fresh air ventilation and humidity control

Lowering your AC to dehumidify your home can cause condensation resulting in mold.

Ultra-Aire dehumidifiers help reduce the risk of serious health issues through filtration, ventilation, and moisture control.

Overcooling your home to control humidity will make you feel uncomfortable and raise your utility bill, and what do you do in spring and fall.