The condenser unit of a mini-split outside a home to the right of a central AC unit

Thanks to its zoned air-handling capabilities, a mini-split heat pump is one of the most efficient ways to cool and heat your home.

But what if you already have ductwork in your home? Can you use one of these heat pump as a central AC system?

This article will explore using a mini-split heat pump as a central AC system. Read on for a rundown of the components you’ll need and some installation tips.

Can a Mini-Split Be Used as a Central AC System?

A mini-split can be used as a central AC system because it provides both heating and cooling. It uses heat exchanger coils in the winter to provide warmth and then reverses the process in the summer to generate cool air.

You can connect multiple indoor units (called air handlers or head units) to one outdoor condenser, allowing cooling or heating of multiple zones. Still, you can connect new heat pumps to the existing ductwork and install integrated controls for easy operation.

How Can Mini-Splits Be Used as Central AC?

Mini-split heat pumps can be used as a central AC system by connecting them to existing ductwork. Using one condenser unit for multiple indoor units is also an option. Remember to get the proper equipment and discuss any conversion with a technician before installation. 

In addition, you can install mini-splits in new construction, eliminating the need for ductwork. As a result, the system can serve as the primary heat source for new spaces without ducting.

Pro Tip: When opting for a mini-split air handler, consider your specific needs and ask a professional about installation options.

The head unit of a mini-split near the ceiling in a common areas of a home above two doors
The air handler unit of a mini-split

How To Connect a Mini-Split to Existing Ductwork

As mentioned, you can connect a mini-split to your existing ductwork. That’s a great option if you’re looking to save on installation costs or if you already have ductwork in place.

When connecting a mini-split to existing ductwork, there are a few things you’ll need to keep in mind, including:

  • First, the size of your unit will need to be compatible with the length of your ductwork.
  • Second, you’ll need to ensure that the heat pump can connect to the ductwork—some models come with adapters that make this process easier.
  • Third, you’ll need to ensure your system can handle the airflow from the ductwork. Most units have no problem doing this, but it’s something to keep in mind.

With these factors in mind, you can begin the installation process. 

Typically, the process involves the following steps:

  1. Mount the indoor air handler onto the wall.
  2. Connect the outdoor condenser to the indoor air handler.
  3. Connect the ductwork to the indoor air handler.
  4. Install integrated controls, if desired.
  5. Finally, supply power to the heat pump and test it.

Caution: Integrating a mini-split with your existing ductwork is a delicate process. Be sure to consult a professional before beginning the installation process. For the best results, let a professional handle the installation from start to finish.

Installing Mini-Splits in New Spaces

If you’re starting from scratch or looking to avoid the hassle of installing ductwork, you can install these systems in new spaces. According to the U.S. Department of Housing and Urban Development, these pumps are an excellent option for smaller homes, additions, or even primary air control systems.

There are a few things to keep in mind when installing mini-splits in new spaces without any ductwork, including:

  • Locationmini-splits need to be installed in an area with some clearance. That allows the unit to circulate air properly and facilitates maintenance and repairs down the road.
  • The number of units – for every square footage of the new space, you need at least 25 BTUs. Therefore, a 1000-square-foot room will need 25,000 BTUs. Check the manufacturer’s guidelines to see how many BTUs the unit produces.
  • Cost – the initial cost of installing a unit can be higher than other systems. But because they’re efficient, you’ll save money on your energy bills in the long run.

Here’s a video demonstrating how to install a ductless heat pump:

Screenshot from a video demonstrating how to install a ductless mini-split heat pump
Courtesy of Alpine Home Air

If you need a ductless mini-split heat pump for your home, buy this MrCool Heat Pump Split System from It has everything you need for a complete installation, including an air handler, condenser, and line set.

It’s one of the most energy-efficient mini-split heat pumps on the market, with a 22 SEER rating.

The Risks of Using Ductwork in a Your AC System

Now that you know how to use mini-split heat pumps as a central AC, it’s time to get familiar with the risks of integrating them into your ductwork.

A few of the risks you should be aware of include:

Small Pumps May Render Ductwork Inefficient

First and foremost, you must ensure the system is compatible with the size of your ductwork. If the unit is too small, it won’t be able to circulate air properly. On the other hand, one that’s too large will put a strain on the ducting and could cause it to break.

Leaky Ductwork Can Reduce Efficiency

Another risk of using ductwork with a mini-split is that the ducting could develop leaks.

The ductwork is not airtight, so it’s normal for some air to escape. But if there are significant gaps or holes, it can significantly reduce the system’s efficiency. According to the University of Florida, such leakage may lead to up to 40% energy loss.

A close of air ducts complete with insulation

Ductwork Can Become Clogged

Over time, the ductwork can become clogged with dust, dirt, and other debris, which can block airflow and reduce the system’s efficiency. In some cases, it can even cause the system to overheat and break down.

To avoid these risks, consult a professional before integrating a mini-split into your ductwork. They can help you choose a suitable unit and ensure it’s properly installed.

Loose Ductwork Can Lead to Noisy Operation

If the ductwork is not correctly connected to the mini-split, it can cause the system to operate noisily. Sometimes, this noise can be so loud that it disrupts your home.

Check the ductwork for loose connections if you notice that your system is making noise. If you find any, be sure to tighten them. If the problem persists, consult a professional.

Ductwork Promotes Mold Growth

Another risk of using ductwork with a mini-split is that it can promote mold growth.

Mold loves dark, damp places, and ductwork provides the perfect environment. Not only is it dark, but it’s also full of moisture.

If you notice mold growing in your ductwork, clean it immediately. If the problem persists, consult a professional.

Humidity in air duct insulation resulting in it corroding

Frequently Asked Questions

Having read all this information, you might still have questions about using mini-splits as a central AC system.

To help you out, we’ve answered some of the most frequently asked questions below.

Can a Mini-Split Be Used for Just Cooling?

Mini-splits can be used for heating and cooling, but you can also use them for AC only. They’re efficient because they circulate air more evenly than window units and don’t take up a lot of space.

Plus, they’re quiet and easy to install so you can use them in any room of your house.

Can a Mini-Split Cool a Whole House?

Mini-splits can cool a whole house. However, it’s important to note that they work best in small spaces. If you have a large home, you might need more than one unit to cool the entire house.

Remember, the model’s rating is for a specific size room. So if you have a large home, you’ll need to factor that into your decision.

Can Mini-Splits Be Used as a Primary Heat Source?

Ductless heat pumps can be used as a primary heat source. However, they’re not as efficient as other heater types in extreme temperatures, so you might want to supplement them with another heat source.

For example, you could use a mini-split during moderate weather and switch to your furnace during the year’s coldest months. That would help you save money on your energy bill.

Is a Mini-Split Considered a Permanent Heat Source?

These heat pumps are considered a permanent heat source. Unlike portable heaters, mini-splits are installed in your home. They’re usually mounted on the wall or ceiling, so they’re not going anywhere.

Besides, they require professional installation, so you can’t just pick them up and take them with you if you move.

A technician adjusts the indoor component of a mini-split

Final Thoughts

Now that you know how ductless heat pumps can be used as a central AC system, it’s time to decide whether to install one in your home.

If you’re ready to install a mini-split in your home, consult with a professional. They can help you choose a suitable unit and ensure it’s properly installed.

A qualified HVAC technician can also answer any questions about using these systems as central AC.


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