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Do ductless mini-split systems work?

When researching heating and cooling systems for your home, it’s easy to be inundated with industry-specific jargon, like “SEER”, “BTU,” and “supply”. But, if you’ve been searching, you’ve probably come across another term: “ductless mini-split.” This is actually less technical than you might think. It’s a type of HVAC system, and it just might be a great fit for your home.

In this article, we’ll review what ductless mini-split systems are, how they work, and what makes them the right option for so many different types of homes and spaces. We’ll also outline some next steps for homeowners who might be interested in adding a ductless system to their home.

What is the difference between a heat pump and a ductless mini-split?

Homeowners quickly learn there’s more to HVAC than just “air conditioners” and “furnaces.” In fact, two increasingly popular home comfort options—heat pumps and ductless mini-split systems—tend to get confused for one another. It’s hard to blame people: they’re often talked about together as “alternatives” to traditional HVAC options. But, despite this, they are not (quite) the same thing.

Both heat pumps and ductless mini-split systems are dual-season systems that provide both cooling and heating—a key differentiator from air conditioners and furnaces, which are both single-season systems.

How do heat pumps and ductless mini-split systems work?

Both heat pumps and ductless mini-split systems accomplish this by reversing the refrigeration cycle in the winter. In the summer, both heat pumps and air conditioners can absorb heat energy and release it outside the home, cooling the inside. But, heat pumps (and ductless mini-splits) can take things a step further, reversing that process in the winter to absorb heat energy from the outside and bring it inside, warming the home.

So, what’s the difference between the two?

It might help to think of a ductless mini-split system as just a heat pump with a different delivery mechanism.
The core difference comes down to the delivery of that cooled and heated air to the living spaces of your home.

Heat pumps, as part of a central heating and cooling system, use a blower to push air out through ducts to registers in different rooms. In contrast, ductless mini-split systems distribute heated and cooled air via wall-mounted air handlers strategically placed throughout the home.

Watch this Mitsubishi video to see a ductless mini-split system in action:

Which is better: ductless AC or central AC?

This really comes down to your home and your comfort needs. Here’s a breakdown of when a ductless mini-split makes more sense than central AC—and vice-versa:

If your home already has ductwork and a setup compatible for central cooling and heating, it might make sense to either install an air conditioner and furnace combination, or talk to your local HVAC professionals about adding a heat pump. The most expensive part of installation (ductwork) is already taken care of, and your home was likely built with central cooling and heating in mind.

On the other hand, if your home does not currently feature ducts—or you’re looking to add indoor comfort to a home addition or disconnected guest suite—you’re probably better off with a ductless mini-split configuration. Ducts can be expensive to install, and many spaces, such as garages and historic homes, may not have been originally designed with ductwork in mind.

Some homeowners with central heating and cooling decide to add a ductless mini-split system to supplement their comfort in certain rooms, such as the kitchen or living room. A ductless mini-split might also be a good choice for a disconnected guest suite (sometimes called a “mother-in-law suite”) that, for obvious reasons, your home’s current ductwork cannot reach.

Can a mini-split heat a whole house?

In most cases, yes. The maximum number of air handlers connected to a single condenser in a mini-split configuration depends on the system itself, but is generally between 5-8. This means a single, multi-zone mini-split system can provide comfort to most American homes, with much larger properties perhaps requiring a second outdoor condenser unit.

This isn’t an exact science: the number of air handlers needed per-room in your home depends on the cooling and heating requirements of said rooms. This, in turn, comes down to factors such as square footage, the number of windows, existing insulation, and other factors.

If you’re considering adding a mini-split to your home, talk to an HVAC contractor and get them out to your property to take measurements and provide you with an individualized quote. This may help you decide whether you move forward or not.

Do I need a mini-split in every room?

Most of the time, no. Depending on the size of your home, the number of stories it has, and how many rooms there are, you may only need a few air handlers throughout the home to adequately cool and heat the space. Most mini-split systems can handle up to 8 interconnected air handlers, but that’s often unnecessary except in the largest of homes.

Many homeowners strategically place their air handlers in spaces where cooling and heating is needed the most. The kitchen is a must-have: as well all know, things can get hot while the oven’s running on a warm summer evening. So is the living room and den, since that’s where families spend most of their time. Little-used guest bedrooms, utility rooms, or entryway rooms may not need their own air handler. However, this is a question that is ultimately best answered by your HVAC contractor.

How efficient are ductless mini-splits?

If they’re installed correctly, a ductless mini-split configuration can be incredibly energy-efficient. Ducts—and, by extent, traditional central AC and heating systems—can lose up to 40% of cooled and heated air before it even gets to the registers and vents of your home. Ductless systems don’t have this problem. Plus, with a mini-split, you can “zone” your home so you only actively cool or heat rooms that you’re using, instead of the home as a whole.

Like all HVAC systems, a ductless mini-split is only as efficient as the home is. Structural inefficiencies—such as leaky window frames or poor attic insulation—are going to drive up your monthly utility bills, just as they would with a traditional central heating and cooling setup. If you’re serious about making your home more efficient, you should work with your HVAC contractor to zero in on these points of inefficiency and address them.

Are mini-splits worth the money?

Yes. Mini-splits are a good investment for a wide variety of homes and spaces. Their versatility and efficiency makes them an excellent option for homeowners who are either looking to move past central AC and heating, or supplement their existing comfort with zoned control.

If you’re interested in adding a ductless mini-split system to your home, talk to a local HVAC contractor in your area and get an assessment from them. They’ll be able to advise you on what type of system will work best for your space, and how much your mini-split setup will cost to install.