How Do Whole-House Dehumidifiers Work?

A whole-house dehumidifier works by removing excess moisture from the air. It integrates directly with your HVAC system. More effective than a portable dehumidifier, the unit treats your home’s entire air volume so its effects reach every room. We’ll now explain how modern whole-house dehumidifiers work and why you should consider installing one.

Full Humidity Control From One Location

An HVAC dehumidifier is installed in the return air duct, which leads back to your main HVAC components. The device’s supply side is connected to the supply plenum, creating a balance that ensures the unit works properly. As warm, humid air is drawn back to your cooling unit, it passes through the dehumidifier, which has an evaporator coil with refrigerant running through it.

Contact with the cool coil causes water vapor to condense into a liquid and water droplets fall out of the air. This occurs before air reaches the AC and circulates through the ductwork. After condensing out of the air, the liquid collects in a reservoir or collection pan or is routed directly to a drain line.

The dehumidifier is about the size of a toaster oven. It activates when the humidity level rises above a preset level. 

The following is a breakdown of the main components of a whole-house dehumidifier:

• Fan: A fan draws humid air into the unit and moves it toward the cooling coils.
• Compressor: This component compresses and expands the refrigerant so the coils in the dehumidifier get cool.
• Reheater: It collects any heat that is generated during the cooling process. 
• Coils: These carry the refrigerant that allows the air to cool so water vapor can condense.
• Reservoir: A plastic bucket that may be removable for manual emptying or attach directly to a pump or floor drain.
• Humidistat: Whole-house dehumidifiers usually have a humidistat that lets you program the desired relative humidity level.

Benefits of Whole-House Dehumidification

Installing a dehumidifier in line with your central HVAC system enables all the air in your home to be treated. Investing in one can have the following benefits:

• Improved Comfort: High humidity can make your home feel warmer. It can also make it feel sticky or clammy. Reducing moisture content leads to a more comfortable living environment.
• Less Condensation: If condensation on windows and other surfaces is common, a dehumidifier can reduce moisture content so this doesn’t happen, preventing mold growth and water damage.
• Increased Energy Efficiency: More balanced humidity levels help your HVAC system run more efficiently, so your utility bills may go down.
• Less Strain on Your AC: Central air conditioners also remove humidity, but too much can strain the system. Therefore, an HVAC dehumidifier reduces the amount of energy your AC uses to provide cooling.
• Healthier Living Environment: A damp home can exacerbate allergies and respiratory conditions. Humidity control can alleviate these problems and inhibit the proliferation of mold and dust mites.
• Protect Your Home: High humidity can damage wood furniture and flooring and absorb a musty odor that lingers well past summer. A whole-house dehumidifier prevents this by providing constant moisture control.

Do I Need a Whole-House Dehumidifier?

At 50% relative humidity, the air may feel slightly heavy. When it’s 70% or higher, wet spots may appear around your home, and, at 80% or more, you may see water seepage or mold on walls. You can measure indoor humidity with a hygrometer, which is an inexpensive instrument. Or, high humidity can make you so uncomfortable that it’s time to find an effective solution. 

Discomfort, high energy bills, and poor indoor air quality affect your well-being. However, an HVAC dehumidifier is an investment in your home that can improve its value along with your comfort and health.

Other signs you may need a more effective dehumidification solution include:

• Mold and mildew
• Roaches, spiders, and other pests
• Foggy windows
• Peeling wallpaper
• Blistering paint
• Wood doors and window frames get stuck
• Creaking floors

How Does a Whole-Home Unit Compare to a Portable One?

A portable dehumidifier removes humidity from only one room at a time. It works similarly to an air conditioner but must be emptied often. You can control the fan speed so, by setting the fan slower, you slow down air movement and the unit can remove more moisture. Portable units aren’t as convenient and also have downsides such as no filter to capture dust and a high power draw.

By comparison, whole-house dehumidifiers are very efficient and run while your AC system is running. They also require less maintenance. User-friendly controls allow precise adjustments of humidity levels. Whole-home systems, while more expensive than portable models, are more effective, operate more quietly, and are installed in an out-of-the-way location near your HVAC unit.

What Size Whole-House Dehumidifier Do I Need?

The size of the unit needed depends on the square footage of your home. The larger your home, the more pints per day (PPD) the unit must remove. The average temperature in your area is also a factor. However, a 1,200-square-foot home with 50% to 60% humidity generally needs a 50-pint system, but if the same home has 80% to 100% relative humidity, a 60-pint unit is required.

A dehumidifier’s PPD rating reveals how much water it can remove in 24 hours. This assumes standard conditions of 80℉ and 60% relative humidity. A 45 PPD dehumidifier is considered a low-capacity model, while a medium-capacity unit is rated at 45 to 50 PPD and a high-capacity model has a 50 to 75 PPD rating.

What Is the Ideal Indoor Relative Humidity?

Ideally, the relative humidity in your home should be 30% to 50%. It is typically at the higher end of this scale in summer and lower in winter. However, indoor humidity isn’t only affected by the weather. Indoor activities such as cooking, showering, and drying clothes can increase humidity. The number of people in your home can too, as breathing also adds moisture to the air.

Why Is My Home So Humid?

Humidity can be produced inside your home. Therefore, a lack of ventilation can contribute to increased moisture levels. Opening windows or running kitchen or bathroom fans can help. Humid air also rises, so air from a damp basement can affect comfort throughout your home, and make the attic extremely uncomfortable. 

The porous nature of concrete allows it to absorb moisture. This moisture can add humidity to the air in the basement, which then rises throughout your home. Sealing the concrete walls of your basement can help, but moisture can enter from other sources, so you may still want to consider installing a whole-house dehumidifier.

How Is an HVAC Dehumidifier Installed?

A stand-alone model is best suited for an unfinished basement and addresses humidity at its source, so can benefit your entire home. You can also install a partially ducted system. It can be ducted to the basement, which is beneficial if the space is damp or partially finished and connected to the rest of your ductwork. A fully ducted unit dehumidifies the entire volume of air flowing through your HVAC system.

How Much Does a Whole House Dehumidifier Cost?

According to Forbes, the cost of an integrated dehumidifier averages $2,000. However, it can range from $1,000 to nearly $3,000. The type of dehumidifier, the amount of work required for installation, and the size of your home impact the total cost. The higher its capacity and efficiency rating, the more expensive the unit. Plus, you must also consider your HVAC contractor’s hourly labor rate and how long installation takes.

Contact Kliemann Brothers

A home dehumidifier is important for many reasons. Humidity levels in Tacoma can vary throughout the year and high moisture can affect your home at any time, especially in the summer. You can depend on our licensed HVAC professionals to test indoor humidity levels and recommend a whole-house dehumidifier that can manage the problem. The right system can prevent moisture damage and protect your air conditioning system, saving you money over time. To learn more or request an appointment, call (253) 201-8498.