Can One Ductless Mini Split Heat And Cool The Whole House?

Can One Ductless Mini Split Heat And Cool The Whole House?

A mini split can heat and cool an entire house. It all depends on how many air handlers are installed throughout the house. A single-zone system with one air handler will only treat one room, but a multi-zone setup can handle all heating and air conditioning. 


As a product manager for the HVAC distributor Pierce-Phelps for well over a decade, I can tell you that mini split heat pump systems have become much more widespread in the Mid-Atlantic area over the past 15 years. 

For a long time, they were really only popular in warmer climates because their heating capacity was pretty low. 

Older models couldn’t really keep you warm once it got below 40 degrees. But, you can buy heat pumps today that do the job even in sub-zero temperatures. 

Through Peirce Phelps, I’ve worked with dozens of contractors in Pennsylvania, New Jersey, Delaware and Maryland. They install hundreds of ductless systems every year.

They keep me updated about the questions that homeowners ask about them. So, I’m addressing a few big questions here: Can a mini split heat and cool your house? And, how does it work, exactly? 

Keep reading to learn what ductless can do — and how. And, if you’d like to learn more about how a system like this can make your home more comfortable, schedule a free consultation with a certified contractor in your area. Use our dealer locater below to find one that’s worked for years in your area.


Can One Mini Split Cool Multiple Rooms?

Ductless mini split systems can be used to cool multiple rooms or an entire house. To do so, the system must be designed to place enough air handlers throughout the house to cover the entire area. Each air handler, or indoor unit, treats a different room. 

Ductless mini splits give you zoned HVAC. That means you can set different temperatures in different rooms. They’re especially good for homes with open floor plans, three stories, and split levels. 

It’s very different from central air. You know, when one thermostat controls the entire house.  

Single Zone Vs. Multi Zone

A single zone mini split system can cool one room or a section of a home. You’ll have one heat pump outside connected to one air handler inside (I’ll explain what that means in a little while). 

This configuration is popular because you can address the heating and cooling in an individual room like a bedroom that’s always too hot or cold.

Elsewhere, a ductless air conditioner for a sunroom can make it an all-seasons room, for instance. Or, get better comfort in a home office without turning off a space heater or window AC for a video call.

On the other hand, multi zone mini split systems can cool multiple rooms. Or, as I mentioned, an entire house. 

Each room, or zone, gets its own indoor unit. You can hook up to eight of these to one heat pump. Most homes require up to five air handlers. But, larger homes or homes with a lot of rooms many need more than that, 

Whole House Mini Split System

A whole house mini split system is designed to cool or heat an entire home with a single outdoor unit and multiple indoor units. In one sense, it’s like a central air conditioning system because you see the one unit outside. But, there are many more difference. 

First, there’s no ductwork — especially great for homes that don’t have that in the first place. 

These systems can also heat your home. We’ll talk about that a little later.

Finally, there’s the zoning: You can set the temperature in each room individually.

This gives you the customization of portable ACs or window units. But without the noise or sky-high electric bills in the winter. 

Ductless Air Conditioning

Ductless air conditioning system works like traditional central air in the sense that it takes the warm air in your house, cools it, and recirculates it. But because there is no ductwork, energy loss is minimized. So, it’s much more effective and efficient than central air conditioning systems.

Ductless Heating

Ductless mini split systems can also provide heat during the colder months. Now, older models didn’t do a great job at this. That’s why you still hear people call these “ductless air conditioners.” 

Back then, people used them for cooling and maybe a little bit of heat. In warmer climates, it was enough for the coldest weather. But they couldn’t provide warmth when it was lower than 50 or 32 degrees outside. 

That’s not the case anymore. Now, you can get a mini split heat pump that works just fine in subzero temperatures — far colder than it gets in the Mid-Atlantic states. 

How Ductless Mini Splits Work

Ductless mini splits work in the winter by absorbing heat from the outdoor air and transferring it to the indoor units. This process works in reverse during the summer. 

Heat Transfer

Air-source heat pumps use the concept of heat transfer to warm or cool your house without transporting air long distances. Instead, only heat – or thermal energy – moves from one area to another by transporting it through refrigerant lines.

That makes it significantly more effective than ducted systems, especially when that thermal energy needs to reach a room far away from the heat pump.


A ductless mini split system consists of three main components: 

Heat Pump

Ductless heat pumps work by extracting heat from the air outside and moving it inside. Or, taking the heat from inside and “dumping” it outside. 

Refrigerant Lines

Refrigerant lines connect the outdoor unit to the indoor units. They run the refrigerant, or coolant, liquid in a closed loop between them. 

Air Handlers

The air handler is the mini split indoor unit responsible for distributing cool air into the room. They are typically installed high on a wall and have a sleek, low-profile design. 

The indoor air handler sucks in the air from the room. That air comes into contact with the refrigerant, which warms or cools it. 

How It All Works Together

In the summer, the refrigerant is cool when it reaches the air handler. It absorbs the heat and sends it down to the heat pump. The air handler blows cool air into the room, while the outdoor unit releases heat. The indoor unit also dehumidifies the air as part of the cooling process.

Ductless mini split heat works the other way in the winter: The refrigerant carries heat, and that thermal energy gets transferred to the cool air that the air handler sucks in from the room. 

Cooling the Whole Home with a Ductless Mini Split

Let’s look at how one mini split for the whole house can keep everyone cool in the summer. 

Case Study: Whole-Home Ductless Cooling In Newark, DE

A family in Newark, Delaware, replaced their aging furnace and central air system with a whole-house ductless mini-split system. The new system uses three indoor air handlers: Two in each bedroom and one in the open-plan first floor. 

Now, they didn’t have to heat and cool the entire house all the time. The family saw their utility bills go down within the first two months of using their new system.

Instead, they could raise the temperature in the bedrooms during the day when no one was up there. They did the same downstairs at night. 

Case Study: Multi-Zone Ductless Air Conditioner Cools Entire Lancaster, PA Home

A family in Lancaster, Pennsylvania opted for a ductless mini-split system to finally get cooling in their entire home. Since they had radiator heat, there was no ductwork for central air. 

The system in their large historic home has seven indoor air handlers and one outdoor unit. And, they still get to choose which rooms they cool and which they don’t. That comes in handy with guest rooms and other areas they don’t always use. 

The result? Better comfort and way lower bills without energy-guzzling window AC units. 

Can You Heat A House With One Mini Split?

A multi-zone mini split system can heat an entire house all winter. It requires multiple indoor air handlers and a heat pump with enough BTU capacity for the coldest months. 

Here are some examples:

Case Study: Mini Split Replaces Oil Heat In Levittown, PA

A homeowner in Levittown, Pennsylvania, replaced their oil heating system with a ductless mini-split system. The new system uses one outdoor unit and four indoor air handlers to heat the entire house. 

Without relying on combustion, the homeowner’s winter bills are way lower than they used to be. And, he doesn’t have to worry about scheduling oil deliveries. 

Case Study: Mini Split Keeps Every Room Warm In South Philly Trinity

A young couple loved everything about their South Philly Trinity — except the temperature on the third floor. The ductwork up there was lousy. The only way to keep it warm was to crank the thermostat until the first floor was too hot. 

Now, the air handlers on the third floor stay on longer than those on the first floo. This gives the homeowners a consistent temperature across the entire house. Along with much better comfort, they’re spending much less on their heating bills. 

Pros of Ductless Mini Splits for Whole-House Cooling And Heating

Ductless mini split systems offer several advantages over traditional HVAC systems, including:

Energy efficiency and cost savings

Forced-air heat and central air conditioning systems waste up to 30% of energy they use due to ductwork limitations. Ductless mini split systems don’t have that problem because they only move heat, not air. That saves homeowners money on their utility bills. 

Mini splits also use inverter technology. So, instead of clicking on and off a few times each hour, the compressor adjusts speed to match the cooling or heating demand of the room. Think of it like cruise control for your heating and cooling. 

Zone control and individual temperature preferences

One of the greatest benefits of ductless mini split systems is zone control. This means that you can set different temperatures in different rooms or zones of your home. 

Traditional forced-air HVAC systems only let you set one temperature in the house. One thermostat, usually in the living room, turns the one furnace/AC system on or off. If the second (or third floor) is hotter than the first floor, it will never get the cooling it needs with this system. 

Improved indoor air quality

Ductless mini split systems remove more airborne particles, allergens, and odors than traditional HVAC. That’s thanks to the multi-stage filtration in the air handlers. And, they’re easy to clean so you don’t have to worry about mold, dust, and other contaminants building up in the ductwork and blowing through the air inside. 

Flexible installation options

Ductless mini split systems are flexible in terms of installation options. You can install them in new construction, retrofit them into existing homes, or add one to a single room. 

They can work alongside existing ductwork for supplemental heating and cooling., Or bypass the ducts and vents entirely. 

Cons of Ductless Mini Splits for Whole-House Cooling And Heating

Yes, these systems offer a lot of benefits. But, they’re not perfect, and they have some drawbacks you should take into consideration as well.

Higher upfront cost than traditional HVAC systems

A multi-zone system can cost up to three times as much as a new furnace and central air setup. This is because each indoor unit requires its own outdoor unit and refrigerant line. And, the parts are more expensive overall since they have many more features. 

You’ll likely make up the difference in savings on your utility bills over time. But, the installation cost is a big consideration. 

Maintenance requirements and potential repairs

You need annual maintenance for ductless mini splits, just like forced-air HVAC. But, you also need a little more than usual. Since they heat and cool, you’ll call your HVAC company for tune-ups in the spring and fall. 

And, the filters are reusable. So you don’t slide in a new one every month like with a furnace. Instead, you need to wipe them down every few weeks. 

Finally, I recommend a deep cleaning once a year. Air handlers can improve your indoor air quality, But they can also make it much worse if you allow dirt, dust, and even mold and mildew build up inside of them. 

Mini Split Heating and Cooling FAQs

You may still have questions about how mini splits heat and cool your home. I’ll answer a few more here. 

How many rooms can a ductless AC cool?

Ductless ACs can cool a single room or multiple rooms depending on the number of indoor air handlers installed. Multi-zone systems can cool up to eight rooms, while single-zone systems are ideal for a single room or small space. 

How many years do mini splits last?

Ductless mini splits usually last for 15 to 20 years if they get the proper maintenance and upkeep. Scheduling regular tune-ups and cleanings, plus cleaning the air filters every month, can ensure the longevity of the system. 

What happens if a mini split is too big for the room?

If a mini split is too large for a room, it can cause short cycling, which is when the system turns on and off frequently, reducing efficiency and increasing wear and tear. That extra stress translates into higher electric bills and a shorter lifespan for the system.

Are you ready to upgrade the comfort with a mini split installation in your Philadelphia, PA home? Use our Dealer Locator to find a qualified contractor that’s served South Central PA, or anywhere in the Mid-Atlantic region, for years. They’ll answer all your questions with a free consultation and estimate.