The short answer: for apartments and other multifamily housing, a permanently installed, drain-connected dehumidifier in each unit is usually the most dependable choice. It works whether or not residents remember to run it, it never needs a bucket emptied, and it can’t simply be unplugged and moved into a closet. Portable units work for a single room in a pinch, and whole-house ducted systems suit larger single-family or common spaces tied to one air handler. The right answer depends on who controls the equipment and where the moisture comes from.
This guide is for owners, developers, property managers, architects and engineers planning moisture control for apartments, affordable and tax-credit housing, student housing and military housing.
Why multifamily buildings have a humidity problem
Modern apartments are built tight to save energy, which also traps the moisture residents create every day: showers, cooking, laundry, plants and people. Units are small, so that moisture concentrates. Air conditioning is controlled by temperature rather than humidity, so a unit can feel cool while relative humidity stays well above the EPA’s recommended limit of 60%. The results show up as musty smells, condensation, mold complaints, damaged finishes and unit turns that cost more than they should.
Unlike a single-family home, the person living with the humidity usually isn’t the person responsible for the building. That one fact shapes the whole decision.
Portable vs. wall-mounted vs. whole-house: side by side
| Portable dehumidifier | Wall-mounted (in-wall / on-wall) | Whole-house (ducted) | |
|---|---|---|---|
| Where it lives | On the floor; can be moved or unplugged | Recessed into or mounted on the wall of each unit | Connected to the HVAC ductwork or suspended from the ceiling |
| Drainage | Usually a bucket; some accept a hose | Continuous drain, tankless | Continuous drain |
| Who controls it | The resident | Set by the property; tamper-resistant options available | The system controller / HVAC controls |
| Coverage | One room | A room or apartment unit | An entire conditioned space served by one system |
| Best fit | Temporary or single-room fixes | Apartments, condos, student and military housing, hotel rooms | Larger homes, common areas and spaces with their own air handler |
Portable dehumidifiers: cheap to buy, hard to rely on
Portables are easy to buy and need no installation, which is why residents often bring their own. In a managed building, their weaknesses are operational: buckets fill and the unit shuts off, units get unplugged because of noise or power bills, and they move out when the resident does. Nobody on the property side can see whether one is running. They’re a reasonable short-term fix for a single room, not a moisture strategy for a building.
Wall-mounted dehumidifiers: built for unit-by-unit control
A wall-mounted dehumidifier puts humidity control inside each apartment, permanently, with a drain connection instead of a bucket. The IW-25-6 IN/ON Wall Dehumidifier is designed for exactly this:
- Capacity: removes up to 40 pints per day (at 80°F and 60% RH) in up to 1,500 square feet
- Independent of HVAC: an integrated humidistat runs the unit whenever humidity rises above its setpoint
- Tankless: continuous drain, nothing to empty
- Four installation options: recessed flush in 2×6 frame walls; semi-recessed with an exterior sleeve in 2×4 walls; through-wall in 2×4 construction; or surface-mounted on any solid wall, including CMU block, masonry, concrete and brick. That covers new construction and renovation alike.
- Property-controlled: user-friendly controls with an optional security cover, and tamper-resistant screws in the box
- Efficiency and comfort: ENERGY STAR certified, with a 2-speed fan (100 cfm high / 85 cfm low)
- Optional remote monitoring with the DehuLink™ Wi-Fi Module, useful for vacant units and managers overseeing many buildings
Where wall space is limited, the HWD-45 Horizontal Wall Dehumidifier from our Defender Series installs above door frames or cabinetry, or in crawl spaces with little headroom for a gravity drain. Its controls sit behind a tamper-proof cover that only the installer or facilities manager can access, and it resumes its settings after a power loss. That makes it a strong fit for barracks, student housing and other institutional buildings.
Whole-house dehumidifiers: when one system serves the space
If a space is served by its own air handler, such as a townhome, a large single-family rental, or an amenity or common area, a ducted whole-house unit can treat all of it at once. Our Professional Series ranges from the WH60 (60 pints per day, AHAM-rated at 80°F/60% RH, for spaces up to 11,000 cubic feet) to the WH200OA (200 pints per day for up to 45,000 cubic feet, with a 6-inch motorized damper for bringing in outdoor fresh air). For individual apartments on shared systems, though, a whole-house unit can’t give each resident’s unit its own control. That’s where wall-mounted units come in.
What it looks like in a real building
At a 400-unit apartment community in Texas struggling with mold, a single test dehumidifier took one affected apartment from 78% to 56% relative humidity within two hours. The owner ordered units for all 400 apartments. Six months later, when mold reappeared in six apartments, the investigation found that those six were the only units where dehumidifiers had never been installed.
A planning checklist for owners and specifiers
- Decide who should control humidity. If the answer is the property, not the resident, plan for permanently installed, tamper-resistant equipment.
- Match the equipment to the moisture source. Unit-level loads call for wall-mounted units; a space served by one air handler can use a ducted whole-house unit.
- Plan drainage early. A condensate drain connection at each location eliminates buckets and missed maintenance.
- Pick the install type by wall construction: 2×6 recessed, 2×4 with sleeve or through-wall, or on-wall for masonry and retrofits.
- Size by square footage and moisture load, and account for bathrooms, laundry and occupancy.
- Budget for simple maintenance: washable filters and a service schedule your maintenance team can own.
Browse installs by building type on our Multifamily Properties and Military pages, and see the costs of high humidity in student housing.
Renting, or still deciding whether a unit needs a dehumidifier at all? Start with Dehumidifier for an apartment: what actually works.
Multifamily dehumidification FAQ
What is the best type of dehumidifier for apartments?
For managed apartment buildings, a permanently installed, drain-connected wall-mounted dehumidifier in each unit is usually most reliable, because it runs automatically, needs no bucket, and stays under the property’s control.
Can a dehumidifier be installed inside a wall?
Yes. The IW-25-6 recesses flush into a 2×6 frame wall, semi-recesses into a 2×4 wall with an exterior sleeve, installs through-wall in 2×4 construction, or surface-mounts on solid walls such as concrete block or brick.
How do you stop tenants from turning off a dehumidifier?
Choose equipment with tamper-resistant controls. The IW-25-6 offers an optional security cover and includes tamper-resistant screws, and the Defender Series HWD-45’s controls are accessible only to the installer or facilities manager.
Is a whole-house dehumidifier better than individual units?
It depends on the building. A whole-house unit treats a space served by one HVAC system. In multifamily buildings where each apartment has its own moisture load and occupants, individual wall-mounted units give unit-by-unit control.
Planning a project? Meet the IDS team at the North Carolina Affordable Housing Conference, September 30–October 1. You can also contact us, call (910) 579-3348, or find a distributor on our Where to Buy page.
