Mini-Split Humidity Problems

Mini-split HVAC systems are one of the newest technological innovations to come to the HVAC residential market. 

These small and efficient systems work well, especially for retrofitting older homes with central HVAC systems. However, mini-split HVAC systems can suffer from humidity problems.

Household humidity problems with mini-split HVAC systems usually is a symptom of an improperly sized unit. A mini-split system that is too large for space cools too fast to remove the household humidity adequately.  

As a homeowner with a mini-split HVAC system, you want the most efficient operation possible. Operating your Mini-split system requires some understanding of how a mini-split system works.

We’ll explain how mini-split HVACs work and how to make them more efficient.

Can a Mini-Split HVAC System Control Humidity?

In many instances, the answer is yes. A properly sized and installed system can help control the relative humidity in your home.

How effectively your mini-split system works is dependent on the quality of the installation and some factors related to your lifestyle.  

Ensuring Efficiency From Your Mini-Split System – Sizing and Installation

Traditional HVAC systems depend on moving conditioned air through the whole house. Mini-split HVAC systems only condition the installed space’s air.

Typically, this is one room of the home. The operation of a mini-split HVAC system tends to be more efficient.    

The efficiency of the mini-split HVAC system depends on several factors.

• The size of the space 
• The size of the min-split system installed
• The way the mini-split system operates

Your HVAC installer must make the correct calculations to ensure that the mini-split system installed in your home is the right size.

If the unit is too small, you will lose efficiency as it runs harder to cool the space. If the mini-split system is too large, the system will run in short bursts, lowering the efficiency.  

In either case, the mini-split HVAC system will operate uneconomically and may not adequately remove moisture from the air in your home.  

Your Homes Characteristics and Location

When choosing and sizing a mini-split HVAC system, the contractor should take into consideration the characteristics of the home, such as:

• The layout of the home. Homes with large open areas or high ceilings have different requirements than a home with low ceilings and many smaller spaces.
• Windows and doors create different demands on a mini-split HVAC system. If your home features many large windows or other openings to the outside, the mini-split HVAC system’s calculations must consider these openings.
• How well your home is insulated and how airtight your home is a big factor in sizing your mini-split HVAC system.  
• Your geographic location can play a role in sizing your mini-split HVAC system. Homes built in the desert southwest of the US have different characteristics and needs than those in the coastal regions.  

Humidity and Your Home – Your Lifestyle and Habits 

Humidity control problems in homes where mini-split HVAC systems are installed may not be related to the system installation.

In some cases, the problems are attributable to the homeowner and the way they operate the systems. These problems stem from several habits.

• Let the Systems Run – Mini-split systems are most economical and efficient when they can run in automatic mode all the time. All the time means all day, every day. Many people try to economize by turning the systems on and off. Let the system manage the HVAC process.
• Open is Better – Leave the interior doors of your home open to encourage air circulation. There are always areas in your home where there is no mini-split system. Hallways, small areas such as mudrooms, entryways, and bathrooms don’t have air handling units. Leaving passageway doors open encourages air movement and more efficient operation.  
• Find Your Comfort Zone and Leave your System There – Pick a comfortable temperature and leave the thermostats set on this temperature. Constantly raising and lowering the settings causes your mini-split system to operate less efficiently.
• Your Lifestyle Can Make A Difference – If you live in a region with high natural humidity, you may need to make a few lifestyle changes. Many people in these regions grow accustomed to leaving exterior doors and windows open. A mini-split system can often become overloaded in this situation as the humidity-laden air constantly enters the home. 

What Affects Humidity and Your Mini-Split System?

Several factors can affect how well a min-split HVAC system works to control humidity in your home. Among these factors are:

• Characteristics of the home including room sizes and layout
• The size of the mini-split HVAC system
• The way the homeowner operates the mini-split system
• Other habits and customs of the homeowner
• The geographic location of the home

Careful consideration when choosing the size of the mini-split system is a must. 

Besides, homeowners may need to adjust their lifestyle. Homeowners must adjust their lifestyle to their new HVAC system to reap the largest rewards.

The Issue of Humidity in Your Home

According to the Centers for Disease Control and the Environmental Protection Agency, the relative humidity in your home should be between 30 and 60 percent.

At this level of humidity, the chances for mold growth in your home lessen significantly.

There are some signs that your home is suffering from elevated humidity levels.
These include:

• Musty odors, especially in basements or tightly enclosed spaces
• Increased allergy symptoms to mold or dust mites
• The sudden appearance of mold growth in your home
• Cupping or bowing of wood floors or trim
• Experiencing mugginess or stickiness
• Condensation on windows or metal surfaces
• Separating wallpaper or peeling paint

If Humidity is a Problem, You Need to Know the Numbers

If you suspect that you have a high humidity problem in your home, the best way to check the actual humidity level is with a hygrometer. Hygrometers measure the amount of water vapor in the air.

Owning one of these instruments is a must for anyone with humidity problems in their home.

Small portable units can be purchased at most home improvement centers and are relatively inexpensive. If you have a mini-split HVAC system, a handheld hygrometer allows you to check the humidity in each zone or room of your home.  

Understanding How your Mini-Split System Removes Humidity

In many ways, a mini-split HVAC system uses the same principles to cool the air in your home as a traditional central HVAC system.

Rather than drawing air from the entire house through a cooling unit, a mini-split system divides this chore into room-sized units.

A mini-split system cools the air the same way. The condensing unit outside the home compresses the refrigerant gas that passes to each of the house’s mini-split systems.

A fan blows the inside air over the refrigerant coils inside the mini-spit system. As the refrigerant gas expands, it chills.

This expansion and chilling cools the air passing over the coils.

Part of the air’s chilling also causes any water vapor in the air to condense on the coils. The collected water drains away.

The condensing of the water vapor lowers the relative humidity in the home. Less water vapor in the air means less humidity in your home.

What are the Advantages of a Mini-Split HVAC System?

There are several outstanding reasons to install a mini-split HVAC system in your home rather than a conventional central HVAC system.

• Efficiency – New mini-split systems are more efficient than older standard central HVAC systems. Standard HVAC Systems collect air from the entire house when running, condition the air, and send it back to the house through ductwork. Mini-split HVAC systems only condition the air in those areas of the house where a temperature difference exists. The means less energy used overall.
• Both Heating and Cooling – Most new mini-split systems can heat and cool the air in the space where they are installed. The technology utilizes a heat pump to provide both heating and cooling from the same unit.

• Cheaper Installation in Older Homes – Often, mini-split HVAC systems are cheaper and easier to install in older homes. A standard central HVAC system requires ductwork to move the conditioned air around the house. Installing ductwork can be difficult in some older homes. Installing a Mini-split system usually involves running small copper lines from the outside unit to the room’s wall-mounted unit. Running refrigerant lines is cheaper, cleaner, and easier than installing ductwork.
• Many Available Options – Recent innovations in designing the mini-split HVAC system’s room units have made them much more attractive and less intrusive. Recessed units are now available that almost disappear into the room décor.  

Can a Mini-Split HVAC System Manage My Humidity Problem

Usually. If the installation is done properly and the right calculations are made to ensure that the system is sized properly, a mini-split HVAC system will easily manage the humidity in your home.

You may need to make some minor adjustments to your lifestyle.  

However, under some conditions, the best planned and installed mini-split system may not adequately manage home humidity.

In these instances, an additional dehumidifier may need to be used to augment your mini-split HVAC system.

Your HVAC representative can advise you more about sizing and using an auxiliary dehumidifier with your mini-split HVAC system.

The Goal of your Mini-Split HVAC System – Keeping Cool and Dry

A mini-split HVAC system can be a perfect solution to your home heating and cooling needs.

In most instances, a mini-split system that fails to deliver the expected results is the product of poor planning and inadequate system design. Working with a qualified HVAC professional can help eliminate most of these problems.

We hope that the information in this article is helpful. Dealing with excess humidity in your home can be challenging, but solutions usually are found with a little understanding and knowledge.