Is dehumidifier good for hot weather?

During hot and humid summer weather, high humidity levels can make indoor air feel muggy and uncomfortable. Many people turn to dehumidifiers to reduce humidity and create a more pleasant living environment when the temperatures rise. But is running a dehumidifier actually helpful for hot weather, or might it make things worse? Here is a detailed look at how dehumidifiers work, their effects on indoor temperature and humidity, and whether they are a good choice for hot summer days.

How do dehumidifiers work?

Dehumidifiers reduce indoor humidity by drawing moist air over refrigerated coils. The coils cool the air below its dew point, causing water vapor to condense and drip into a collection tank. The dehumidified air is then reheated and circulated back into the room. This process continually extracts water from the air, lowering the relative humidity level. Dehumidifiers work most effectively at higher ambient temperatures, when the air can hold more absolute moisture. Hot summer conditions create ample opportunities for dehumidifiers to remove large amounts of water from the air.

The refrigeration cycle

The refrigeration system inside a dehumidifier is similar to an air conditioner’s cooling cycle. A compressor pumps refrigerant through the system, pushing it into a condenser coil. The refrigerant condenses from a gas to a liquid state in the condenser, releasing its heat. The liquid refrigerant passes through an expansion device and enters an evaporator coil, where it boils back into a gas. This phase change extracts heat from the air blowing over the evaporator, cooling it below the dew point. Moisture condenses and drips into the collection tank. The refrigerant returns to the compressor and repeats the cycle.

Reheating the air

After being cooled for dehumidification, the air passes over a reheating coil. This adds back some of the heat that was removed and raises the air temperature so it feels comfortable when it exits the dehumidifier. The reheating process also prevents the dehumidified air from overcooling the room. However, it requires additional energy input, reducing the dehumidifier’s efficiency.

Effects of dehumidifiers on temperature and humidity

Operating a dehumidifier affects both the temperature and humidity level indoors:

Humidity: Dehumidifiers directly reduce the relative humidity by removing moisture from the air. They are highly effective at lowering humidity levels during hot weather when the air moisture content is high.

Temperature: Dehumidifiers slightly warm the reheated air they output, increasing the room temperature. However, the temperature rise is usually minimal. The dehumidification process itself liberates heat that can also warm a space. Eliminating humidity reduces the heat index, making indoor conditions feel cooler.

The interactions between temperature, humidity, and perceived comfort are complex. But in general, dehumidifiers make hot indoor environments feel more pleasant by lowering the humidity even though temperatures may rise slightly. The drier air feels cooler against the skin. Dehumidifiers improve comfort most noticeably when the relative humidity is above 60%.

Do dehumidifiers heat or cool a room?

Dehumidifiers remove heat and moisture from the air. The reheating process puts some heat back, but only enough to prevent overcooling the space. The net effect is a slight cooling through latent heat removal. However, dehumidifiers lack the capacity to actively cool and significantly lower temperatures. They largely affect comfort by reducing humidity levels.

Are dehumidifiers energy efficient?

Dehumidifiers require electrical energy to operate the refrigeration system and fans. The amount of power consumed depends on the unit’s moisture removal capacity and efficiency. Here’s how the energy use of dehumidifiers compares to other appliances:

Capacity: A typical 50-pint dehumidifier uses around 580 watts of power. Large whole-house dehumidifiers can draw over 1000 watts.
Efficiency: Energy Star rated dehumidifiers remove moisture using 20-30% less energy than conventional models.

Comparison: Dehumidifiers use about as much power as small window air conditioners but generally run for fewer hours per day. They consume far less energy than central AC systems.

While dehumidifiers are relatively efficient for moisture removal, running one uses more electricity than not using one. During hot weather, the increased energy costs are often worthwhile to keep humidity at comfortable levels. But it’s still important to use energy-saving features and properly size the capacity.

Tips for energy-efficient operation

Look for the Energy Star label when selecting a dehumidifier.

Choose a unit sized appropriately for the room based on square footage.
Set the humidity level higher, often 50-55% relative humidity is adequate.
Use timer settings to avoid unnecessary runtime.

Clean air filters and coils per the manufacturer’s instructions.
Locate the dehumidifier away from heat sources.

Ideal placement for dehumidifiers

Proper dehumidifier placement optimizes moisture removal and efficient operation:

Living spaces: Place the dehumidifier in an open area central to the apartment or house. This allows air circulation through doors and hallways.
Basements: Position the unit near the basement stairs where damp air naturally enters from the ground. Point the airflow outward toward the room.
Crawl spaces: Install the dehumidifier to pull moisture directly from the crawl space rather than adding ductwork.

Bathrooms: Use a smaller dehumidifier made for single room operation. Place it along a wall near the shower.
Laundry rooms: Position the unit away from the dryer, where it can draw in the moist exhaust air and condense the moisture.

Avoid placing dehumidifiers directly adjacent to heat sources like lamps, televisions, or heating ducts. Allow adequate clearance for air intake and output. Follow the manufacturer’s installation guidelines for proper placement.

Ideal settings for dehumidifier operation

Adjusting the target humidity level and fan speed impacts a dehumidifier’s performance and efficiency:

Humidity setting: For summer conditions, aim for 50-60% relative humidity. This balances comfort and energy use. The optimal setting depends on personal preference.
Fan speeds: Use auto-humidity mode or low fan speed to maintain the target humidity. High fan speed causes excessive drying and energy use unless actively drying the space.

Drainage: Draining to a floor drain removes water more efficiently than emptying the bucket. This improves dehumidification, as the unit won’t shut off when the tank is full.
Maintenance: Clean the air filter every 1-2 weeks to allow proper airflow. Annually clean dust from coils.

Avoid running the dehumidifier below the target setting or on high fan speed at all times. Let the unit run continuously to maintain indoor humidity levels. Turning it on and off frequently reduces efficiency. A hygrometer helps monitor relative humidity.

Are dehumidifiers safe to run?

When operated according to the manufacturer’s directions, dehumidifiers are safe appliances for home use. However, take these precautions for optimal safety:

Follow electrical requirements – Use a grounded outlet with the appropriate amperage rating. Avoid overloading circuits.
Allow adequate ventilation – Don’t obstruct air intake or output. Maintain clearance from walls and furniture.

Keep away from water – Don’t use in wet areas or position where water can splash onto the housing.
Ensure proper drainage – Don’t allow the collection tank to overfill and leak. Drain to a sink or condensate pump if possible.
Monitor operation – Make sure the dehumidifier doesn’t vibrate excessively, overheat, or trip your electrical breakers.

Secure the unit – Keep the dehumidifier upright and stable to prevent tipping over. Don’t operate if damaged.

Children and pets require close supervision around dehumidifiers to avoid accidental injury or electric shocks. Avoid unnecessary direct contact with the appliance during operation.

Potential risks

Rarely, manufacturers recall dehumidifiers due to defects that create safety hazards. These have included:

Fire risks from short-circuiting defects.
Burn and shock risks from faulty wiring.
Tip-over risks if the unit is unbalanced.

Water leakage risks from drain hose problems.

Research indicates any risks are minimal when consumers follow operational guidelines and use trusted brands that adhere to safety standards. The benefits normally outweigh the small chances of a hazardous defect.

Indoor air quality improvements

Along with making the air feel more comfortable, dehumidifiers can also improve indoor air quality:

Reduces allergens and irritants – Lower humidity limits growth of mold, mildew, and dust mites.
Prevents musty odors – Dry air stops spaces from smelling stale or damp.
Reduces condensation and chances of mold – Moisture on surfaces promotes mold growth in hot weather.

Improves air conditioning efficiency – Removing humidity allows AC systems to cool more effectively.

The optimal relative humidity for indoor air quality is around 50%. Dehumidifiers help maintain this target to minimize pollution sources and create a cleaner home environment.

Potential air quality risks

There are a few possible downsides to running a dehumidifier:

Excessive drying can worsen dust and allergens by making particles airborne.
Improper drainage can lead to water spills that promote mold if not cleaned up.
Reduced ventilation from closed windows prevents fresh outdoor air from entering.

With balanced use and proper maintenance, dehumidifiers provide a net gain for indoor air quality in most homes during hot, humid weather conditions.

Alternatives to dehumidifiers

Other methods besides dehumidifiers can reduce indoor humidity levels and associated discomforts:

Air conditioners

Air conditioners cool air below its dew point to remove moisture similarly to dehumidifiers. Running AC systems with a moderate thermostat setpoint of around 75°F provides dehumidification. But ACs are more costly to operate and energy intensive. Portable dehumidifiers are a cheaper alternative for supplemental humidity control.

Ventilation

Increased ventilation exchanges indoor air for drier outdoor air, naturally lowering humidity. This requires opening windows and doors, using ceiling fans, or running a whole house fan. Ventilation is simple but lets in heat, pollen, and other outdoor irritants.

Desiccant dehumidifiers

Desiccants like silica gel absorb moisture rather than condensing it like refrigerant coils. The material requires periodic drying to restore the moisture absorption capacity. Desiccant dehumidifiers have benefits like no noise and high efficiency in low temperatures. But availability is limited and they can be costly to operate long-term.

DIY moisture absorption

Placing bowls of salt or charcoal in rooms will slowly absorb some moisture without electricity. This is only practical for small spaces. The absorption capacity is minimal compared to mechanical dehumidifiers or AC systems.

For whole home humidity control during hot weather, dehumidifiers provide the most effective and cost-efficient solution in the majority of cases.

Potential drawbacks of dehumidifiers

While beneficial for lowering humidity levels, dehumidifiers also have some inherent disadvantages:

Higher energy bills – Electricity use can add up, especially for large-capacity units running extensively.

Noise – The compressor and fan create audible noise, an issue for light sleepers.
Maintenance – Air filters must be changed and parts cleaned to maintain effectiveness.
Reduced portability – Dehumidifiers work best in a fixed spot with permanent drainage. Moving them frequently is inconvenient.

Other minor drawbacks include aesthetics, possible allergens in the dust filter, and taking up floor space. Compare the benefits of lower humidity to any of these disadvantages for your specific situation.

Troubleshooting common dehumidifier issues

Several problems can arise with dehumidifier operation and effectiveness:

Issue	Potential Causes	Solutions
Not collecting water	Dirty filters, coils Room temperature too low Humidity setting too high	Clean filters and coils Ensure room is above 65°F Lower humidity setting
Ejecting warm air	Unit placed adjacent to a heat source Refrigerant charging issue	Relocate the dehumidifier away from heat Have an HVAC technician service the refrigerant
Frozen evaporator coils	Low room temperature Dirty filters and coils Refrigerant issue	Operate unit above 41°F Clean the filters and coils Check refrigerant charge
Not lowering humidity	Excessive moisture source Unit undersized Dirty filter and coils	Eliminate moisture source Size up to a larger capacity Clean filter and coils
Fan not working	Obstructed air intake Loose wiring Broken fan	Clear intake and allow airflow Inspect electrical connections Replace fan motor

Following operating guidelines and troubleshooting according to the user manual can resolve most dehumidifier issues without professional assistance. For more difficult repairs, contact the manufacturer or a skilled HVAC technician.

Summary

Dehumidifiers provide an effective method to reduce humidity and improve comfort levels during hot, humid weather:

Dehumidifiers work by cooling air below the dew point to condense moisture, then reheating the air before circulation.
They remove large amounts of moisture from the air most readily in hot conditions.

The reduced humidity improves thermal comfort even though temperatures may rise slightly.
Optimal placement and settings further enhance the effectiveness and energy efficiency.
Lower humidity improves indoor air quality by limiting mold, dust mites, and allergens.

Some alternatives like ventilation or desiccants exist, but have disadvantages for whole home use.

For managing humidity in an energy efficient manner across large interior areas, dehumidifiers are generally the simplest and most practical solution during hot weather. Their ability to moderately lower the perceived temperature by drying the air outweighs small inefficiencies. Proper use and maintenance keep operating costs reasonable in relation to the benefits. Consider your specific conditions, but in most homes a dehumidifier can make hot indoor spaces far more comfortable.