Small Apartment Dehumidifiers: Size, Noise, and Drain Options

Sizing a dehumidifier for a small apartment

The most important spec for any dehumidifier is capacity, measured in pints per 24 hours. ENERGY STAR's guidance groups spaces into small-medium rooms (under 2,000 sq ft) and large rooms (over 2,000 sq ft). For a small apartment, you are almost always in the small-medium category. If the space feels slightly to moderately damp, with a musty odor that may be intermittent and relative humidity between 50 and 75 percent, ENERGY STAR recommends a capacity of 20 to 30 pints per day. For a very damp space that consistently feels and smells wet, with damp spots on walls or floors (75 to 90 percent humidity), you want 25 to 40 pints. For a truly wet space, like one with condensation or seepage, 30 to 50 pints is the range.

Keep in mind that the U.S. Department of Energy changed the test procedure starting in 2020, lowering the reported capacity of many models. The new test uses cooler, basement-like conditions, so a unit rated 30 pints under the old method may now be rated 20 pints. When you compare models, always check the current pint rating, not the one from a few years ago. Oversizing is generally better than undersizing, but for a compact apartment a 20 to 30 pint unit is often plenty. If you are unsure, measure the room and estimate the humidity level, then pick a unit from our best under 50 pints guide or the best up to 1,500 sq ft guide.

For a typical studio or one-bedroom apartment, you do not need a commercial unit. A portable dehumidifier that you can move from the bedroom to the living area works well. If you have a bathroom or kitchen that stays damp, a smaller unit may be enough. The key is to get a machine that can keep indoor relative humidity below 50 percent, as recommended by the CDC to prevent mold growth.

Noise: Keep it quiet in tight quarters

In an apartment, walls are thin and the unit often runs in a bedroom or living area, so noise is a real concern. Portable dehumidifiers have a compressor and a fan, both of which produce sound. The decibel level varies by model, but you will not find official decibel ratings on the ENERGY STAR page. However, you can look for units that advertise quiet operation, and you can check the noise level in the product specifications. A typical portable dehumidifier runs around 40 to 50 decibels, which is comparable to a refrigerator hum or a quiet conversation. For sleeping, you may want a unit with a lower decibel rating or one that you can place in a hallway or bathroom with the door closed.

Some units have a dedicated 'quiet' mode or a fan-only setting that reduces noise. Others have a timer so you can run them during the day and let them cycle off at night. If you are sensitive to noise, consider a desiccant dehumidifier, which uses a different process and is often quieter than a compressor model, though we do not have specific numbers here. Our article on noise levels and decibels explains how to compare ratings, and the quiet specs for a bedroom guide offers more targeted advice.

Placement also matters. Put the dehumidifier a few feet away from walls and furniture so air can circulate freely. Avoid placing it directly next to your bed or sofa. If you have a bathroom with an exhaust fan, running that fan while the dehumidifier operates can cut down on the amount of moisture the unit needs to handle, which may allow you to run it on a lower, quieter setting.

Drain options: bucket, hose, or pump

How you remove collected water is a practical decision in a small apartment. Most portable dehumidifiers come with a removable bucket that you empty manually. ENERGY STAR notes that these units typically have a warning light and automatic shutoff when the bucket is full, so you will not have to worry about overflow. The bucket size varies, but you will likely empty it once or twice a day in a damp environment, depending on the pint rating and humidity level.

If you prefer a hands-off solution, look for a model with a drain hose connection. Many units have a fitting that lets you attach a standard garden or vinyl hose, which can be routed to a floor drain, a sink, or even a bathtub. In an apartment, a floor drain may not be available, but a sink or a toilet is often an option. Our continuous drain hose setup guide explains how to attach and position the hose correctly.

When gravity drainage is not possible because the drain point is above the unit, a built-in condensate pump can lift the water uphill. Some dehumidifiers include a pump, or you can buy an external pump. The pump pushes water through a small tube to a sink or other drain, which is ideal for apartments with a high counter or a raised sink. Our built-in pump versus gravity drain article covers the trade-offs, and the pump vs. bucket comparison can help you decide. For models with a pump, see our best dehumidifiers with a pump guide.

If you are renting, you may not want to modify plumbing. In that case, a bucket unit is the simplest and most portable option, and it requires no installation. Just remember to empty it regularly and to clean the bucket to prevent mold or odors.

Energy efficiency and operating costs

A dehumidifier runs continuously, so energy use matters, especially in an apartment where electric bills can be a concern. ENERGY STAR certified models use about 20 percent less energy than conventional units of the same capacity, thanks to more efficient coils, compressors, and fans. The energy efficiency metric is called Integrated Energy Factor (IEF), which measures liters of water removed per kilowatt-hour. A higher IEF means better efficiency. Since June 2019, all new dehumidifiers are required to use the IEF rating, based on a test procedure that reflects real-world basement conditions.

When shopping, look for the ENERGY STAR label. The ENERGY STAR dehumidifier guide lists certified options. You can also see the IEF explained article for a deeper dive into how the metric works. In a small apartment, a 20 to 30 pint unit typically consumes less energy than a larger 50 pint model, so you are already on the efficient side. But the IEF still varies, so compare models by their liters per kilowatt-hour. The Department of Energy sets minimum efficiency standards, so any new unit will meet those baselines, but ENERGY STAR goes further.

To save even more, place the dehumidifier where it can work most efficiently. Close windows and doors when it is running, and avoid using humidifiers or drying clothes indoors while it operates. You can estimate your running cost from the unit's IEF and your local electricity rate, but even without exact numbers, choosing an ENERGY STAR unit is a safe bet.

Keep humidity low to prevent mold

The main reason to use a dehumidifier in an apartment is to control mold and moisture. The CDC recommends keeping indoor humidity no higher than 50 percent all day. Mold can grow on any damp surface within 24 to 48 hours, as the EPA notes. Using a dehumidifier helps maintain that low humidity level, especially in rooms with poor ventilation like bathrooms, kitchens, or closets.

The EPA also points out that the key to mold control is moisture control. Fix any leaks, use exhaust fans when cooking or showering, and dry wet areas promptly. A dehumidifier is a powerful tool, but it works best when you also reduce the sources of moisture. For example, do not leave wet towels on the floor, and avoid boiling pots without a lid. Our recommended humidity settings article explains what target humidity to set for different rooms.

In a small apartment, you might not have a basement, but you still have bathrooms, kitchens, and possibly a closet under a sink where mold can appear. A compact dehumidifier can be moved to target these areas. For a bathroom, a small unit can help control condensation after showers. See our bedroom and bathroom dehumidifier guide for models that work well in these spaces. Remember, the goal is to keep the air dry enough that mold never gets a chance to start.

What to pick for your small apartment

Questions

What size dehumidifier do I need for a 500 sq ft apartment?

For a 500 sq ft apartment, a 20 to 30 pint unit is usually sufficient for moderately damp conditions. If the space is very damp or wet, size up to a 30 to 40 pint model. Check the ENERGY STAR sizing chart for exact recommendations.

Are small dehumidifiers quiet enough for a bedroom?

Many small portable dehumidifiers operate around 40 to 50 decibels, similar to a fan or refrigerator hum. Look for models with a quiet mode or a timer, and place the unit away from your bed. Our bedroom quiet specs guide can help you compare.

Can I run a dehumidifier continuously with a drain hose?

Yes, many portable units have a hose connection that allows continuous drainage into a floor drain or sink. You must position the hose so that gravity does the work. If the drain point is above the unit, you need a pump model instead.

Is it better to buy a dehumidifier with a pump or a bucket?

A pump model lets you drain water to an elevated location, which is handy in an apartment. A bucket is simpler, cheaper, and requires no installation, but you must empty it regularly. Choose based on your convenience and whether you have a suitable gravity drain.

How often should I empty a dehumidifier bucket in a small apartment?

It depends on the humidity level and the unit's capacity. In a damp apartment, a 20 pint unit may fill its bucket once or twice a day. The bucket full indicator and auto shutoff prevent overflow, but you should check it regularly.

Will a dehumidifier lower my electric bill?

No, a dehumidifier uses energy, so it will increase your bill slightly. However, an ENERGY STAR certified model uses about 20 percent less energy than a standard unit, which saves money over time. The savings from preventing mold damage can also offset the operating cost.