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Advantages And Disadvantages Of A Ductless HVAC System


Minnesotans love the great outdoors. But keeping the great outdoors outside is the reason HVAC systems were invented! We expect our homes and workspaces to be comfortable indoors throughout the year, and that’s why HVAC systems are always improving and innovating. The most common type of HVAC system in Minnesota uses a series of ductwork, vents, and grilles to bring comfort to your home.

But, what if your home doesn’t have vents and ducts — like many older homes with radiators and steam heating? Or, what if you want to add a room to your home or convert a porch for year-round use, but don’t want the mess of installing new ductwork? For situations like these, many homeowners opt to use a ductless HVAC system.

What is a Ductless HVAC System?

A ductless system is a type of zoned heating and cooling system that doesn’t use or require the installation of ductwork. It’s reversible in that it produces both heating and cooling for the room or zone in which it’s installed. These systems are also referred to as “ductless split systems” or “mini-splits” because they’re composed of two parts.

First, there is a condensing unit that sits outside the home, just like traditional air conditioning. The second part is an indoor air-handling unit called a “head.” There may be multiple heads, depending on the specific needs and configuration of the system. The indoor heads are generally mounted toward the top of the wall and are connected to the outdoor compressor by a dedicated line. Each consists of a coil and blower, which directs the airflow into the room. Each head corresponds to a heating/cooling zone and can be independently controlled, usually by remote.

How Does a Ductless System Work?

Using vapor compression, ductless systems capture heat from outside the house and distribute it indoors when heating and reject indoor heat, returning cool air on the cooling cycle. The systems use variable speed compressors capable of matching the heating or cooling needs without the on/off cycling of conventional systems, which contributes to their high efficiency.

So, why are these systems beneficial? And what are their drawbacks?


Ductless systems are smooth running, quiet systems that provide the comfort, convenience, and worry-free cooling or heating you need. These systems are:

Highly Efficient

Ductless systems use as much as 25-50% less energy than other systems, making them highly efficient. That also means they’re likely to recoup their purchase and installation costs quickly. Because the systems are zoned, they can also save on energy costs because there’s no need to overheat or over-cool rooms that are used infrequently.

Cost Effective

A ductless system will save on energy costs because they're so efficient. Plus, they’re much less expensive to install if you just need additional heating or cooling in a room or two. For example, if you have an area of your home that’s hard to heat or cool, are adding a room, or converting a porch to a four-season room, it may be too expensive to upgrade your entire central HVAC system. But installing a ductless system will get the job done economically.

Space Saving

Ductless systems can fit in a variety of spaces that ducts can’t. A ducted system can take up a lot of valuable real estate in your home by filling up attics, basements, or thick walls with the ducts themselves. Duct-free systems are a space-saving solution that can provide comfort in non-ducted areas, making them as comfortable as any other space in your home.


While they’re the obvious choice for small jobs. “They are great in homes with no ductwork – such as homes with baseboard heat or in-floor heat,” our expert, Keith Hill, technical support manager for Minnesota Air explains. “They’re also great for additions, three-season rooms, and in rooms where some extra cooling or heating is needed."

Easy to Install

Installing a ductless system is quick and easy, with far less mess and renovation than ductwork would require. A ductless system can be installed in just a few hours. 

"The big advantage of the system is, being ductless, there is little impact to the home," Keith says. "A typical installation is the indoor unit located high on an outside wall and some tubing run out the back and down the exterior wall to the condensing unit outside. Most of these systems use a wireless remote, so no thermostat or thermostat wiring is needed.”


As efficient, flexible, and cost-effective as they are, ductless systems aren’t perfect for every situation. You should consider these drawbacks when deciding on installing a ductless system in your home.

Ventilation Air

Keith says one of the disadvantages of a ductless system is that outside air – or ventilation air – can’t be integrated into the ductless system like it can in a ducted system. “In a central system, outside air can be brought in to a central location and distributed throughout the home,” he says. "But without ducts, that feature isn’t available."

Central Unit Add-Ons

Think of all the cool additions that can be added on to a central heating or cooling system – whole house humidifiers, dehumidifiers, air cleaning, and air purifying systems. Ductless systems aren’t able to use any of those because there’s no ductwork to distribute the airflow throughout the entire home.

Upfront Costs Can Be High

If you’re planning on doing an entire home using a ductless system, the upfront costs can be high, according to Keith. “If your goal is to cool a multi-room home to the same level of comfort as a central unit, you will need an indoor terminal unit in each room,” he says. “With newer multi-head units – one outdoor unit with multiple indoor terminal units ­– it can be less expensive than multiple single head ductless systems. But one indoor head in every room will add up to be much more than a ducted central system.”

The Department of Energy agrees that the main disadvantage of ductless systems is the cost. According to their website, “such systems cost about $1,500 to $2,000 per ton (12,000 BTU per hour) of cooling capacity. This is about 30% more than central systems (not including ductwork) and may cost twice as much as window units of similar capacity.”

So, depending on your project and home’s needs, ductless may be the answer to your problems. You’ll just need to weigh the advantages and disadvantages of going ductless before you make the leap. While you’re deciding, keep in mind the places ductless systems work best.

Where is the Best Place to Install a Ductless System?

Ductless systems are perfect for supplementing existing systems. For example, if you have a room or an area of your home — say the basement — that’s always colder than the rest of the house, a ductless system could be a cost-effective solution. This is particularly true for Minnesotans and other upper Midwest residents. A ductless system can also be an excellent solution for a home addition or expansion project. 

Similarly, if you’re looking to add or supplement cooling in your home, a ductless system could be the answer. In homes without existing ductwork, such as those with hot water or hydronic heat, ductless cooling provides comfortable air conditioning combined with great dehumidification, far better than window units.

Finally, your business or office could also benefit from the installation of a ductless system. Businesses are often even more varied in their comfort needs than homes. From restaurants to offices to warehouses, ductless systems can solve a variety of heating and cooling challenges. There are even ductless options for climate-sensitive rooms like storage or data areas that require a high degree of temperature consistency.

Does it Matter if a Home is Newer? Older?

Steam heating was very popular in the ‘50s, ‘60s, and earlier, so it’s common that an older home may not have ductwork. Even homes built in the ‘70s and ‘80s frequently had hot water baseboard heat – also with no ductwork. Many homeowners cool these homes with window air conditioners – or what some HVAC pros call “window shakers!”

While window units may cool adequately, they have several drawbacks: they tend to be noisy, aren’t great at removing humidity, take up precious window space, and can be a pain to install and remove with the changing seasons. That’s where a ductless system can come in really handy. Not only are they high-efficiency units, but they are very quiet and do a great job of removing humidity.

Time for Better Cooling in Your Home?

When the time comes to seriously consider quiet, high-efficiency air conditioning that does a great job on humidity removal, the ductless systems are a perfect option. As Keith sums up, “these mini air conditioners are great little problem solvers. And I can’t emphasize enough how quiet they are and what a great job they do on dehumidification.” At Stay Comfy, we recommend the Carrier systems, which can solve almost any cooling problem your home may have.

Depending on your home or business needs, Carrier has a full range of ductless options that may be the answer to your HVAC challenges. Find out which innovative ductless system is right for you!

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