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Ultra Aire MD33
Patent Pending
Ⓓ Therma-Stor, LLC

MD33 In-Wall Dehumidifier

The Ultra Aire MD33 In-Wall Dehumidifier is an innovative, affordable, and proactive approach to prevent issues created by too much moisture, including:

Mold Remediation  •  Property Damage  •  Poor Indoor Air Quality
Comfort and Health Complaints  •  Reputational Risk and Liability

Part Number: 4035900
Blower: 155 CFM @ 0.0″ WG
Power: 324 Watts @ 80°F and 60% RH
120 Volt, hard-wired, electrical can be routed through bottom or out the back of the cabinet
Cord: Optional 10′ cord with plug end
Automatic Restart: Yes
Current Draw: 2.8 Amps
Energy Factor: 2.0 L/kWh
Operating Range: 49°F – 95°F
Sized For: Up to 1,200 Square Feet
Minimum Performance at 80°F and 60% RH
Water Removal: 33 Pints/Day
Efficiency: 4.25 Pints/kWh
Controls: Digital dehumidistat control internally mounted behind tamper-proof cover
Air Filter: 1/2″ Washable – mounted behind diffuser
Dehumidistat: Digital dehumidistat control internally mounted behind tamper-proof cover
Cabinet: Galvanized Steel
Cover: Tamper-proof, access lock-out
Decibels: 46 dBA
Drain Connection: 3/4″ O.D.
Drain Hose: 10′ gravity fed (3/4″ I.D.) hose, routed through the back, side, or bottom of the unit
Refrigerant Type:
Refrigerant Amount:
10 oz.
Coils: Electrophoretic coated coils – prevents corrosion and extends life of the unit
Utility Connections:    Accessible from front for blind installation
Width: 14 3/16″
Height: 30″
Depth: 5 3/4″
Unit Weight: 39 lbs.
Shipping Weight: 57 lbs.
MD33 Spec Sheet

Recommended Installation

Alternative Installations

Ultra Aire MD33 Engineering Specifications
In-Wall Dehumidifier


As people age, their bodies naturally become more sensitive to cooler temperatures. Unfortunately, this sensitivity is often amplified by the increasing number of health problems that plague seniors and the medications used to help. As a result, designing mechanical systems for senior housing to effectively control moisture and keep residents comfortable can be a big challenge. Extending air conditioning run times to remove excess moisture and control humidity is not an option if the goal is comfort. The Ultra Aire MD33 is the first true in-wall dehumidifier that can mitigate the risks associated with excess moisture in buildings, while greatly increasing resident comfort by precisely controlling indoor humidity levels.

Case Study


Guarding against the potential damage inflicted by excess moisture in affordable housing can be a full-time job. Reduced air conditioning run times, coupled with required fresh air ventilation and the activities of residents, can lead to a host of moisture problems, including mold. The Ultra Aire MD33 is the first true in-wall dehumidifier designed to protect the building and the residents by eliminating excess moisture and the conditions that lead to microbial growth. By precisely controlling indoor relative humidity levels, residents are more comfortable and the health risks associated with poor indoor air quality are greatly reduced.

Case Study


Mold has become a very common problem in student housing across the country. Most buildings feature shared bathrooms and kitchens, with a large number of occupants utilizing these facilities 24-7. Year-round dedicated moisture management is a must in order to protect the structural integrity of the building and to maintain a healthy environment for students. The Ultra Aire MD33 In-Wall Dehumidifier, with its discreet tamper-proof design, controls humidity in the spaces that need it the most to prevent microbial growth that can lead to allergies and other serious health problems.

Adaptive Reuse

Adaptive reuse is the process of retrofitting old buildings for new uses, which allows structures to retain their historical integrity while providing for residents’ modern needs. These projects typically offer the financial benefit of tax credits to incentivize developers. As part of the retrofit, envelope and mechanical system upgrades are often at the top of the list, as buildings will have to meet current codes focused on energy efficiency. For some historic properties, certain building features may need to be preserved as well. Unfortunately, combining the ‘old with the new’ often times results in moisture control challenges that cannot be resolved by a traditional HVAC system. The Energy Star® certified Ultra Aire MD33 is the first true in-wall dehumidifier that can mitigate the risks associated with excess moisture in adaptive reuse buildings by allowing for precise control of indoor humidity levels.

Market Rate

Americans spend roughly 65% of their time in the home. Maintaining a proper humidity level is one of the most important steps in providing a comfortable and healthy living environment for residents. Excess moisture promotes harmful indoor air particles, including mold, bacteria, viruses, and dust mites, which can all trigger respiratory problems. In addition, spaces with excess moisture will be uncomfortable – regardless of the temperature. Relying on an air conditioner to reduce moisture will typically only lower the temperature and create a cold and clammy environment. The Ultra Aire MD33 is the first true in-wall dehumidifier designed to protect the home and residents by reducing humidity levels that cause discomfort, smelly odors, and indoor air quality problems. The unit is considered an integral part of any comprehensive HVAC system.


Mold and mildew growth in guest rooms are a serious problem that property managers struggle to avoid, as it often leads to customer complaints and liability claims. The current moisture control strategy employed by most hotels is to leave rooms permanently air conditioned, even when unoccupied, to control humidity and prevent microbial growth. Besides consuming a large amount of energy, this solution does not resolve the problem, as most air conditioning systems are oversized for the space and ultimately create cold and clammy environments with wet surfaces. The Energy Star® certified Ultra Aire MD33 is the first true in-wall dehumidifier designed to protect each room by providing optimum comfort for guests and eliminating excess moisture, which can lead to mold.

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