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

A whole house can be efficiently heated and cooled with a single ductless mini split system. The setup needs enough air handlers installed throughout the house to treat each room. And, the heat pump must be strong enough for winter weather.

By contrast, a single-zone system, with only one air handler, can only regulate the temperature in one room.

Having worked as a product manager at HVAC distributor Pierce-Phelps for over a decade. I’ve seen first-hand just how many homeowners in the Mid-Atlantic region have adopted mini split heat pump systems over the past 15 years.

Before that, you usually only saw heat pumps in warmer areas due to their lower heating capacity. In the past, older models of heat pumps were not effective in keeping a home warm when the temperature fell below 40 degrees.

However, modern air-source heat pumps are capable of functioning in sub-zero temperatures. However, the HVAC contractors I work with across Pennsylvania, New Jersey, Delaware, and Maryland install hundreds of these annually.

They also get a lot of questions from homeowners. There’s still a good deal of confusion about what these systems do, how they do it, and what their capacity is.

So, I’m using this article to answer two crucial questions: Can a mini split system provide both heating and cooling for your whole home? And how do these systems work?

Single Zone Vs. Multi-Zone Ductless Mini Split Systems

A single-zone ductless mini split system consists of one outdoor unit and one indoor unit that cools and heats one room, or zone, in your house. Multi-zone systems have several indoor units connected to one or more outdoor units to heat and cool multiple rooms or zones.

The cooling capacity of a single indoor unit or air handler is typically 6,000 to 1,200 BTUs. The general rule of thumb is 20 BTUs for every 20 square feet. That means a 1,200 BTU system isn’t strong enough for a whole house. The air handler can’t draw in air from another room or floor.

The number of BTUs required to cool a whole house depends on the size of the house, the number of windows, insulation, and other factors. But it’s often around 20,000 for a 1,000-square foot house and 40,000 for a 2,000 square-foot house.

So, you’ll need a multi-zone setup with enough air handlers to cover each part of the house. And, enough combined BTU capacity for your home’s specific cooling load needs.

Single Zone Ductless Air Conditioner And Heating Examples

While a single ductless mini split indoor unit may not be enough to heat and cool your home, it can be sufficient for one or two rooms. Here are some examples:

Ductless Air Conditioner For A Sunroom in Haddonfield, NJ

A homeowner in Haddonfield, NJ installed a single-zone ductless mini split heat pump system to make their sunroom more comfortable year-round. Our Peirce Phelps-associated contractor installed the system in less than a day.

It works independently from the home’s main thermostat and ductwork to keep that sunroom at the perfect temperature even in the bitter cold and sweltering heat.

Home Office in Bensalem, PA

A homeowner in Cherry Hill, NJ, wanted to create a comfortable home office in their garage now that he works from home. They found a trusted contractor to install a single-zone ductless mini split system with an air handler strong enough for a two-car garage.

The additional heating and cooling barely makes a blip on his utility bills. Thanks to its whisper-quiet operation, he can leave it on when he’s taking a call.

Multi-Zone: Whole House Mini Split Heating And Cooling

Now, let’s get into examples of multi-zone mini splits:

Will a ductless air conditioner cool a whole house?

You can get cooling with one mini split for the whole house. The number of indoor units depends on the size of the house and the number of rooms.

Case Study: Ductless Air Conditioning In Older Havertown, PA Home

A Boyertown, PA family installed a multi-zone ductless mini split system in their older home without ductwork. It consists of a single outdoor unit and five indoor units: two on the first floor and one in each bedroom.

Now, they’re enjoying cooling throughout the house all summer with cozier heating in the winter. And, their energy bills are way lower without window units for AC and a gas-guzzling furnace.

Can you heat a house with just a mini split?

Yes, a mini split can be used for both heating and cooling a house. A multi-zone ductless mini split system can provide both heating and cooling to an entire house.

Case Study: Mini Split Heating In Cherry Hill, NJ New Construction

A new construction home in Cherry Hill, NJ, was designed with a mini split heating system in mind. Since it was nearly 4,000 square feet, the homeowners didn’t want to deal with a ducted system using two furnaces and ACs to reach every room without losing pressure.

Now, each room stays at the perfect temperature. And, each room looks a little bigger than other houses on the block without big, bulky ductwork running through them.

Load Calculations

An HVAC contractor must perform complex load calculations to determine the appropriate-sized mini split system needed for a house. These calculations take into account the size of the house, the insulation, the number of windows, and many other factors.

Without the right load calculation, you could end up with a system that’s too large or small for the space. Both extremes are a problem. The system won’t hold the temperature where you want it, and it will break down from being overworked.

How Ductless Systems Work

Ductless mini-split systems work by moving heat, not air, through the house. It does this with indoor and outdoor units connected by lines that run through and across the walls.

What Is A Ductless Heat Pump?

The heat pump is the outdoor unit of a ductless mini-split system. It houses a compressor and condenser coil, and has a fan on the side.

Heat Transfer Process

Ductless heat pumps work by extracting heat from the outdoor air and delivering it indoors during the winter months. During the summer, it works in reverse to take the heat from indoors and release it outside.

Air Handlers

The indoor air handlers contain the evaporator coil, air filter, and a fan. It sucks in air from the room where it’s located and then circulates conditioned air in its place.

Heat Transfer

The heat transfer process is the name for how a heat pump moves heat into or out of the house. This is especially significant in the winter: Instead of burning oil or gas, it draws in ambient heat from the outside air, amplifies it, and uses it to keep your home warm.

It works using refrigerant that circulates between the indoor and outdoor units. The refrigerant absorbs heat from the indoor air and releases it outside, cooling the indoor space.

In heating mode, the refrigerant absorbs heat from the outdoor air and releases it inside, warming the indoor space.

Refrigerant Lines

The refrigerant lines connect the indoor and outdoor units. The lines contain refrigerant that carries heat. The lines are typically made of copper and are well-insulated to prevent heat loss or gain.

Connecting the Indoor and Outdoor Units

The indoor and outdoor units are connected by a conduit that passes through a small hole in the wall. The lineset contains the power cable, refrigerant tubing, suction tubing, and a condensate drain.

Pros and Cons of a whole house mini split system

Is a mini split the best choice to cool and heat your entire home? Here’s what to consider:

Advantages Of A Ductless Mini Split System

Ductless mini split systems offer several advantages over traditional central air conditioning systems:

Amazing Comfort

You can control the temperature in each room or zone individually. Plus, the air handlers offer more precise temperature control than forced air. These features eliminate hot or cold spots and keep the temp within a degree of the thermostat setting all the time..

Flexibility And Customization

You can pick and choose the rooms you want to treat. Heat or cool just one zone, a few rooms, or the whole house. Set each zone to a different temperature if you want, or set them all the same.

Energy Efficiency

Ductless mini split systems use less energy than traditional central air conditioning and heating systems. These significant energy savings mean lower utility bills.

No Ductwork Necessary

Ductless mini split systems do not require ductwork, making them an excellent option for homes without existing ductwork or for homeowners. Installation is fast and easy, with no demolition or construction.

Super Quiet Operation

Ductless mini splits operate literally as quiet as leaves rustling outside. Compare that to the roars of forced-air or especially old window ACs.

Disadvantages Of A Ductless Mini Split System

As great as these systems are, you should also weigh some potential disadvantages:

Upfront Cost

The long-term savings on energy bills can be significant. But the initial investment is much higher than traditional central air systems. A furnace and AC costs $7,000 to $12,000 installed.

A whole-house mini split can run up to $25,000. You pay less on your bills over time and get better comfort. But, you still need to be ready for the sticker price.

Air Handlers Are Large

The air handlers in a ductless mini split system are more prominent than vents f;lush against a wall or floor. And, you need them in every room you’re treating.

Dirt and Debris (And More) In the Components

Air handlers draw in dirt and debris, and are dark and damp inside. That makes them prime breeding grounds for mold and mildew. You can keep the units clean by wiping down the filters every month. But you also need an annual deep cleaning to avoid bacterial and mold buildup.

Federal and State Rebates and Incentives for High-Efficiency HVAC

Local utility companies offer incentives for homeowners who choose high-efficiency HVAC systems, including ductless mini split systems. These incentives can help offset the initial cost of the system and make it more affordable for homeowners. The federal government also offers tax credits for energy-efficient HVAC upgrades. And, you can now apply for rebates via the Inflation Reduction Act.

Frequently-Asked Questions About Whole House Ductless Air Conditioning

I’ve tried to cover everything about how you can heat a house with just a mini split. But keep reading if you have more questions. Or, reach out to one of our network dealers. They’ll go through everything you need to know with a free consultation.

How many rooms can a ductless AC cool?

A ductless AC can cool multiple rooms, depending on the system’s capacity and the layout of the house. One multi-zone ductless system can cool up to eight rooms using a single outdoor mini split heat pump.

How many years do mini splits last?

Mini splits can last up to 20 years or more with proper maintenance. Ductless systems require regular maintenance to reach or pass the two-decade mark. Homeowners can clean the filters every month. Professional HVAC technicians are needed for spring and fall tune-ups and an annual deep cleaning.

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

A mini split too big for the room will short cycle, or turn on and off too frequently. This causes inefficient cooling or heating, increased wear and tear, and higher energy bills. A professional installer performs a load calculation for a right-sized system.