Heat pumps are an efficient and environmentally friendly way to heat your home. There are many different types to choose from, and the decision between a ductless or ducted pump is worthy of careful consideration.
Mini-splits are HVAC systems that allow heating and cooling of specific rooms or zones in a home instead of the whole structure. They are equipped with two primary components—an indoor air-handling unit and an outdoor condenser or compressor.
However, there is a bit of confusion among homeowners as to whether these systems are ductless or ducted.
Well, we’re here to set the record straight.
Are Mini-Split Heat Pumps Ductless or Ducted Central Air?
Mini-split heat pumps can be ducted or ductless. Well-known HVAC brands offer multiple types of both ductless and ducted heating and cooling systems. Ducted systems send air around the building by ducts and into rooms via vents. Ductless blow air directly into the house via a single internal air handler.
There are many choices to be made when designing your heat pump system and whether to go for ducts or not is just one of them.
Let’s look at the differences between ducted and ductless heat pump systems so you can decide which one is right for you.
What Is a Ducted Heat Pump?
As you might imagine, a ducted heat pump system provides warmth to your home via a network of ducts distributed around it.
Also known as ducted central air systems, they are comprised of the main heat pump and an air handling unit. The central unit produces warm air and blows it along the network of ducts and through vents into the rooms being heated or cooled.
These systems are prevalent in newly-built homes because the ducts can be designed into the fabric of the building easily and unobtrusively. If your home was built in the US during the 21st century, you probably have pre-existing ducts already installed.
Central air systems often take up quite a bit of space because of the ducting requirements, so retrofitting ducts can be challenging.
Types of Ducting Used with Mini-Split Heat Pumps
There are two main duct types widely used with mini-split systems—rigid ducting and flexible ducting.
Rigid Ducting
Rigid ducts are often seen in commercial buildings and are sometimes installed in plain view, with no attempt to conceal them from the users of the building.
Usually constructed from metal, they are exceptionally durable, and some are even large enough to crawl through, as demonstrated by Bruce Willis in the famous movie ‘Die Hard.’
Although if you’ve seen the movie, you will know that the metal isn’t thick enough to be bullet-proof!
One drawback of rigid ducting is its tendency to be a little noisy due to the hard reflective surfaces of the ducts transmitting the noise of the blower, often quite long distances. This characteristic is probably why we tend not to see them in domestic houses—their use is normally restricted to commercial buildings.
Flexible Ducting
An alternative to rigid ducting, which is often seen in domestic houses, flexible ducting tends to be cheaper and more straightforward to install.
Flexible ducting is made up of a series of interconnected tubes that can bend around obstacles and be installed in tight areas that are unsuitable for rigid ducting. Although they can be successfully installed in cramped spaces, homeowners must take care to avoid kinks and extremely tight bends that will reduce the efficiency of circumfluent air through the system.
Flexible ducts are made from a metal skeleton encased with flexible plastic and insulating material. Easy to work with and usually cheaper than rigid ducts, they are popular with homeowners and HVAC technicians alike.
What is a Ductless Heat Pump?
In contrast to a ducted system, a ductless heat pump does not use ducts to move air around the building. The systems are comprised of a compressor located outside the building and an indoor air handler tied together by refrigeration lines.
Ductless mini-split heat pumps are very efficient and are a good choice for use in an affordable net-zero house, as covered in our article on the topic here.
Single Zone and Multi-Zone Heat Pump Systems
These mini-split units come in two main types, single-zone and multi-zone.
The single-zone option usually has a single outdoor compressor tied to one indoor head unit, generally in the main living space, such as a living room or kitchen area.
The multi-zone version also has a single outdoor compressor unit, but this single unit is complete with up to four internal head units. The interior components come in different designs, including wall hanging units, floor recessed, or cassette.
As there is no need for ductwork, ductless heat pumps are well suited to retrofit projects where ducts have not previously been installed. They are easier to install and tend to be more efficient because they deliver heat directly to the target area and do not suffer from the heat losses associated with leaky ductwork.
If you suspect you have leaky ductwork, you can find more information about how to fix that in our Beginner’s Guide to Air Duct Sealing, which provides three proven methods for fixing this common problem.
Pros and Cons of Ducted and Ductless Systems
Here is a quick comparison of the pros and cons between ductless and ducted systems.
Ducted Mini-Split – Advantages
- Unobtrusive vents provide an “invisible” heating system for your home.
- Great at removing humidity compared to ductless systems.
- Better air quality—ducts tend to deliver a greater volume of air, which prevents a build-up of odors and stuffiness.
Ducted Mini-Split – Drawbacks
- Unless you already have ducts installed, ducted will likely prove more expensive.
- Ducts require regular maintenance and routine checks to ensure they remain free from leaks.
- Under the wrong conditions, mold can develop—bad news if you suffer from asthma or allergies.
Ductless Mini-Split – Advantages
- Capable of maintaining different temperature zones in the house.
- Ductless systems take up less space in your home.
- Easier installation than ducted systems.
Ductless Mini-Split – Disadvantages
- Require an indoor air handler unit, which some consider obtrusive.
- Lower airflows mean less ventilation from the system.
Is Ductless Better than Ducted for Heating or Cooling Your Home?
Heat pump and air conditioning systems require careful design and must be tailored to meet the specific needs of your home.
If your home already has ductwork installed, it makes sense to use it and install a ducted system.
However, if you are retrofitting a mini-split heat pump in the absence of pre-existing ductwork, the cheaper and less disruptive option would be to go for a ductless system. A ductless system comes with the benefit of operating multiple temperature zones, but some might find the indoor air handlers something of an eyesore.
Whether a ductless or ducted system is the best option for your project is ultimately a decision for you and your HVAC provider.
Our Key Takeaways
- Mini-split heat pumps come in both ductless and ducted varieties.
- Ductless is easier and cheaper to install, but many find the discreet vents of ducted systems more pleasing to the eye than a wall-mounted air handler.
- If you already have ducts in your home from your existing heating system, it makes sense to install a ducted central air heat pump that can tap straight into the existing duct network.
- However, if your property doesn’t have pre-existing ducts then the ease of installation could swing your decision towards a ductless heat pump.
- Whatever you decide, make sure you get good advice from a hired professional who will be able to guide you through the pros and cons of each type as they relate to your specific needs.
If you would like to read more about how efficient and eco-friendly ductless heat pumps are, take a look at this article, which covers the topic in more detail.
Thanks for writing about this topic. Going ducted or ductless usually is not in the minds of the consumers when buying heat pumps. Usually, ordinary users like me only check on how I can save efficiently on electricity and how easy to access it. Happy to know that there many types of ducts to choose from which I usually wonder when I see it from our office buildings.