Open Floor Plans: Choosing a Dehumidifier With Enough Reach

Open floor plans change the sizing question

In a home with closed rooms, you can match a small dehumidifier to each space. In an open floor plan, the kitchen, dining area, and living room share one volume of air. The sizing question is not which room the unit sits in, but how large the combined space is. That total area is what you should compare with the unit's square-foot coverage rating.

ENERGY STAR says the capacity you need depends on two factors: the size of the space that needs to be dehumidified and the conditions that exist in the space without dehumidification. For an open plan, treat the whole open area as one space. Our guide to sizing by square footage walks through measuring it.

Why open layouts affect a dehumidifier's reach

Open floor plans have no interior walls to stop humid air from moving. That helps a dehumidifier in one sense: air from the kitchen can reach the unit more easily than it could through a closed door. But the unit must also draw air from a larger distance, so it needs enough fan airflow to pull moisture from the far end of the space. A model that handles a single bedroom can struggle to keep a great room dry at the far end.

Moisture sources become shared, too. Cooking steam, shower moisture, and damp laundry all enter the same air mass as your seating area. The CDC says mold grows where there is moisture and that an air conditioner or dehumidifier helps keep the level low. Venting kitchen and bath fans outside reduces the load on the dehumidifier. Placement also changes how much of the space the unit can influence; see dehumidifier placement tips for where to put it.

Specs to check for even coverage

Four specs matter most for an open layout: pint capacity, square-foot coverage, airflow, and water removal. Pint capacity tells you how much water the unit can remove in a day. ENERGY STAR's testing page explains that capacity is defined as the amount of water removed per day at test conditions and identifies the relative amount of moisture a dehumidifier can remove. Larger, wetter rooms need higher capacity.

• Square-foot coverage: match the rated coverage to the total open area, not the smallest room in the plan.
• Airflow (CFM): the fan moves air through the unit. Higher airflow helps an open space pull air from farther away.
• Water removal: for long running hours, a drain hose or condensate pump keeps the unit working without emptying the bucket. See continuous drain hose setup for details.
• Efficiency: an ENERGY STAR certified model uses more efficient refrigeration coils, compressors, and fans to remove the same moisture while using 20% less energy.

Capacity guidance for open areas

ENERGY STAR publishes capacity ranges based on room size and dampness. For an open floor plan, use the larger room column when the open area is over 2,000 square feet, and the smaller room column when it is under 2,000 square feet. These are minimum recommendations; ENERGY STAR notes it is better to oversize than undersize.

Capacity ratings changed in 2020. The DOE sets the test procedure for residential dehumidifiers, and portable units are now tested at 65°F rather than 80°F, so current ratings can look smaller than older ones. ENERGY STAR's correlation table shows, for example, an old 50-pint portable rating roughly matching a new 30-pint rating. Efficiency is reported with the Integrated Energy Factor (IEF), which includes the energy the dehumidifier uses when it has cycled off. When comparing older and current models, confirm which rating standard the number refers to; the pint rating explained article covers this.

One large unit or several smaller ones

A single large unit in a central location often covers a true open plan, because air moves freely. ENERGY STAR describes portable room dehumidifiers as typically used to dehumidify a single room or space and easily moved where needed. If your floor plan is open in one area but connects to a hallway of separate bedrooms, one unit may not cover everything. Compare one large versus multiple small dehumidifiers before deciding.

For homes with central ducts and consistently high whole-house humidity, a whole-home dehumidifier is another option. ENERGY STAR notes that whole-home dehumidifiers are typically installed to use your home's air ducts to dehumidify one or more rooms and are often permanent. See portable versus whole-house dehumidifiers for the trade-offs.

Placement and moisture control

Where you place the unit matters as much as its size in an open plan. Put it in a central spot where air can circulate around the intake and outlet, and keep doors to the open area open so moisture can reach the unit. The EPA says the key to mold control is moisture control. The CDC recommends keeping humidity in your home as low as you can, no higher than 50%, all day long.

Also reduce moisture at the source. The EPA says to dry water-damaged areas and items within 24-48 hours to prevent mold growth. The University of Minnesota Extension advises using fans to send moist air outside when cooking or showering and recommends a dehumidifier for damp basements. For operating setpoints, see recommended humidity settings.

What to pick for your use

Questions

Does an open floor plan need a bigger dehumidifier?

Usually, yes. Open plans combine several rooms into one air volume, so the unit has to cover more square footage and pull air from farther away. Compare the unit's coverage rating with the total open area, and use the larger room column in the ENERGY STAR capacity table when the space is over 2,000 square feet.

What does reach mean for a dehumidifier?

Reach is not an official spec, but it describes how effectively a unit can pull humid air from the far end of a space. In an open plan, reach depends on fan airflow, placement, and capacity. A higher airflow (CFM) rating helps move air through a large open area.

Where should I put a dehumidifier in an open floor plan?

Place it centrally, away from walls and large furniture, with the intake and outlet clear. Keep doors to the open area open so air can circulate. If one end of the space stays humid, move the unit closer to that end or add a second unit.

Should I buy one large dehumidifier or two small ones?

For a true open plan, one large unit in a central spot is often enough. If the floor plan has separate zones or closed bedrooms off the open area, two smaller units or a ducted whole-home system may do a better job.

How high should I set the humidity in an open floor plan?

The CDC recommends keeping indoor humidity as low as you can, no higher than 50%, all day long. If parts of the home still feel damp at that setting, look for a higher-capacity unit and address moisture sources such as cooking steam and bathroom humidity.