Can You Add a Dehumidifier to an Existing HVAC System?

can you add a dehumidifier to an existing hvac system featured photo

Nothing is more frustrating than seeing mold and mildew growth in your home. If you already own an HVAC system but still suffer from poor indoor air quality, welcome to the club. Consider getting a dehumidifier to maintain moisture levels and prevent mold. 

You can add a dehumidifier to an existing HVAC system to reduce humidity levels in your home. This equipment can also prevent mold growth and provide comfort during humid days.

However, consider the size of your home and other factors before installing a dehumidifier. This article will teach you how to add a dehumidifier to HVAC systems and its benefits. But first, let us cover what dehumidifier means. 

What Is a Dehumidifier?

What Is a Dehumidifier

A dehumidifier is an appliance designed to remove moisture from the air. And in turn, it reduces humidity levels in a room.

A dehumidifier works by pulling in air through a vent. It passes the gas through cold coils that use a refrigeration system or a desiccant material to cool air. Once the air temperature drops, the moisture condenses into water droplets. These droplets collect in a built-in tank or get drained through a hose. 

Then, the remaining air passes through another set of coils that are warm. These condenser coils heat the gas and eventually release it into the room.

Most dehumidifiers come with a humidistat to monitor moisture levels in the room. This device allows you to set the desired humidity range. It also automatically shuts off once it meets your needs.

Overall, a dehumidifier is an essential piece of equipment for regulating humidity levels in your house.

Can You Add a Dehumidifier to an Existing HVAC System?

If you already have an existing HVAC (Heating, Ventilation, and Air Conditioning) system, you are probably wondering if you need a dehumidifier. After all, an air conditioner can already remove moisture from the air.

However, sometimes, central air conditioners cannot keep up with the moisture levels in your home. Most aircon units also shut off once they reach the desired temperature. Hence, they are unable to maintain humidity over time. That is when a dehumidifier comes in handy.

You can add a dehumidifier to an HVAC system to regulate moisture constantly. It is essential if you live in humid environments. You can also rely on this device to improve overall comfort in your home.

Note that a dehumidifier is unnecessary if you live in a climate without excess humidity. For instance, if your house is in a desert area or the Great Plains, drying the arid air does not make any sense.

What Are the Benefits of Using a Dehumidifier with an HVAC System?

You can enjoy several advantages when you add a dehumidifier to HVAC systems.

First, a dehumidifier can regulate moisture levels in your home. Hence, it prevents nasty mold and mildew growth.

Additionally, this device can minimize odors that come from mold, mildew, and stagnant air.

Besides mold, a dehumidifier also removes other microbial contaminants to promote healthy indoor air quality. It can help alleviate symptoms of allergies and asthma.   

Another benefit of using a dehumidifier is improved comfort. It can reduce excess moisture in the air that makes you feel hot and sticky. It also helps cool down your room.

Dehumidifiers can even preserve your belongings. Since they control humidity, they minimize damage to sensitive items like artwork, books, electronics, and musical instruments.

Finally, dehumidifiers lower utility bills and save energy. They can help your air conditioner cool the room quickly and more efficiently. 

Whole-House vs. Stand-Alone Dehumidifier: Which One to Choose?

You have two main options if you want to add a dehumidifier to your existing HVAC system. 

A whole-house dehumidifier is designed to remove excess moisture from the air in your entire home, hence the name. It is installed directly into the ductwork of your heating, ventilation, and air conditioning system. It provides centralized dehumidification and ensures greater efficiency. However, it requires professional installation. 

Meanwhile, a stand-alone dehumidifier works independently from your HVAC system. It can reduce humidity levels in a specific room or localized area. And unlike a whole-house dehumidifier, it is not permanently installed and portable. It allows you to use the device in different rooms as needed. Unfortunately, it is unable to regulate moisture levels in large areas.

Both types of dehumidifiers have their pros and cons.

Choose a whole-house unit if you need centralized dehumidification or if you have a large room. You can also rely on these units to lower energy costs in the long run. However, expect higher upfront costs for whole-house dehumidifiers.

In contrast, get a more affordable stand-alone dehumidifier if you have a tight budget. You will also find this unit more flexible and easier to install. Plus, you can quickly move the device to another room as needed. The only downside is its limited coverage. 

Is a Whole-House Dehumidifier Worth the Cost?

Yes, a whole-house dehumidifier is worth the investment if you have a large home in a humid climate. It can help regulate moisture from the air in your entire house. It also offers long-term savings because it promotes energy-efficient HVAC units and prevents damage to furniture. It can even enhance the value of your property. Potential buyers may find the added comfort and improved indoor air quality enticing. 

But if you own a small house in an area with low humidity levels, a whole-house dehumidifier is unnecessary. Consider a stand-alone dehumidifier instead if you need to reduce moisture in your home.

How to Add Dehumidifier to HVAC Systems?

Below is a step-by-step guide on adding a whole-house dehumidifier to your HVAC system.

Consider the Size and Relative Humidity of Your House

The first thing you must do is measure the size and humidity levels in your home. Doing so will help you determine the appropriate capacity of the dehumidifier to purchase. Contact a professional if you are unsure about the requirements to look for.

Choose a Suitable Location

After assessing your needs, you can start looking for a suitable location for your dehumidifier. The most common place is in the basement or utility room, where the HVAC system is also located. This way, you can conveniently access the HVAC unit and return duct. 

Install a New Return Duct

This step is optional.

Some homeowners prefer connecting their dehumidifier to the existing return duct of the HVAC system. However, this method can prevent both devices from operating efficiently. 

If you want to ensure optimal performance, install a new return duct in your home. In two-story houses, you only need to set up a single duct on the first floor. Ensure this dedicated return to supply has its grill, like your HVAC unit.

Set Up the Dehumidifier

Once you have installed a return duct, you can set up the dehumidifier. Consult the product manual for specific instructions on how to assemble it.

Mount the device properly before plugging it into a power source. 

Connect the Duct to the Air Supply Plenum

You must attach a duct from the dehumidifier to the supply plenum.

The supply plenum is the main air distribution box connected to your HVAC system. It is also the same place where the dehumidifier returns the dry air. Then, this gas enters your home through the HVAC unit to control humidity levels.

Overall, it is important to create a clear pathway from the dehumidifier to the HVAC system.

Adjust Static Pressure As Needed

Operating the dehumidifier and air conditioner unit simultaneously can increase static pressure within the system. It is essential to monitor this pressure using appropriate tools.

If you notice the pressure exceeds safe levels, adjust the dehumidifier settings. You can choose to operate the device independently of the HVAC system to keep static pressure low.

Monitor Indoor Air Quality

Regularly observe the dehumidifier and HVAC device to ensure they are working properly. You should also test the humidity levels in your home and see if anything improved. If not, you can always make the necessary adjustments to achieve healthy indoor air quality.


You can expect several problems when your HVAC system cannot regulate humidity properly. Consider adding a dehumidifier to minimize moisture levels in your home. This device gives you several benefits, which we have already explored above.

Do you have other questions about dehumidifiers? Feel free to send your queries by visiting our contact page!

Related Articles