Article • June 12, 2024

Ducted vs. ductless heat pumps: A clear choice

A Quilt Indoor Unit with a wood cover mounted on a wall in the hallway of a modern house.
For a healthy, comfortable home, the ductless mini-split is the right pick.

You’ve officially joined Team Heat Pump, recognizing that heat pumps provide the most efficient, planet-friendly way to heat and cool your home. Now you’re deciding whether you want to invest in a central, ducted heat pump or a ductless mini-split system. 

While there’s a lot to consider, Quilt is firmly Team Mini-Split. Our founders spent years measuring the differences and comparing the pros and cons between ductless and ducted, landing on mini-splits for a host of reasons. 

Our conclusion: The ductless mini-split is more efficient, with a less invasive installation process. It saves you money over time and it also gives you, the homeowner, way more control. Unlike ducted heat pumps, you can heat or cool the rooms you want, when you want to. 

Need more convincing? Let’s dive deeper. 

The 3 core benefits of ductless mini-splits

There are three main advantages of ductless mini-split heat pumps that put them ahead of ducted heating and cooling systems: efficiency, ease of installation, and room-by-room control. 

1. Ductless mini-splits are more efficient 

Ducts inherently waste energy, due to leaks and thermal energy loss. Mini-splits don’t use ducts to distribute conditioned air, so they don’t risk the same kind of energy loss. 

The connections between a ductless system’s indoor and outdoor units are precise and sealed during the installation, leaving fewer places for mini-split systems to risk air leakage. And, since the refrigerant lines that connect the indoor and outdoor units are well-insulated and aren’t as likely to be exposed to unconditioned air, there’s very little potential for thermal loss (when the outside temperature affects how hard the system has to work). 

A ductless system has to produce much less energy, because it’s not making up for air lost to leaky ducts. It’s also not wasting energy heating or cooling unoccupied rooms (more on this later). This translates to lower energy bills and fewer emissions. 

2. Ductless mini-splits are easier to install

The installation process for a mini-split heat pump system tends to take less time than its ducted counterpart, and it's much less disruptive to the home. Instead of ducts, the mini-split heat pump network is connected by a conduit, a small cable that gets wired throughout the house. The conduit contains the power cable, refrigerant tubing, suction tubing, and a condensate drain line, which gets run from the indoor unit through the conduit hole and connected to the outdoor unit. 

To connect the conduit to the right places, a technician will only drill a small hole in the wall. There is no need to add ducts or expand your existing ducts, the two HVAC projects that are the most invasive and time-intensive.

3. Ductless mini-splits offer personalized, room-by-room control

The indoor units for mini-splits are sectioned by zone, giving you the power to adjust the temperature individually by room — meaning different rooms can be different temperatures.. 

This capability lets you decide which rooms to condition, a feature that saves energy (and money). An example of a practical use case: When your kid is away for the day at school, their room doesn’t need heating or cooling. You can turn off this particular unit for the day, while conditioning the occupied spaces of your home. Quilt’s system goes a step further, employing its smart technology to learn room occupancy patterns and detect when rooms are empty, and reserving energy as a response. 

With Quilt, room-by-room control lets you manage the output of each indoor unit with either the Dial or the mobile app — you don’t even have to be home to up the heat when you know grandma’s stopping by for a visit. 

Traditionally, mini-splits have come with clunky remote controls that tend to get lost in the couch. Quilt gave this antiquated technology an update so you never have to rummage through cushions to make the room warmer or cooler. 

The problems with ducted systems

Ducted systems offer central heating and cooling, and sometimes pre-existing ducts can be used alongside a new system. But neither central conditioning nor old ducts are necessarily beneficial for homeowners. Let's get into the specifics below.

1. Leaky ducts and wasted air

Leaky ducts are seemingly the rule, not the exception, when it comes to ductwork. It’s estimated that a typical house with a ducted, forced-air system loses anywhere from 20 to 30 percent of the air that moves through the system thanks to leaks, holes, and poorly connected ducts, according to Energy Star. In other words, ducted systems are inefficient. 

Beyond leakage, ducts are prime environments for thermal loss. In lay person’s terms: Ducts are often installed in places that are under-insulated, where the air is not conditioned — think attics, basements, and crawl spaces. These environments are colder in the winter and hotter in the summer, and can influence the temperature of the ducts. 

For this reason, the system has to work harder to get the conditioned air flowing within the ducts to maintain the proper temperature. This translates to higher energy bills and increased emissions.  

2. Heating and cooling unoccupied rooms

Central systems heat and cool every room the same way. This sounds like a good thing, until you realize it means even unoccupied rooms will be heated or cooled. So whether someone’s around to enjoy the conditioned air or not, you’re still paying for the system to run. 

3. Limited control

The way central systems run lack consideration for how people work: We’re all different. Some people want their home office to be cooler, while keeping the baby’s room a cozier temperature. The central system offers no such choice here. 

4. Pre-existing ducts aren’t always a great fit

It makes sense to consider a central heat pump system when your house already has a network of ducts in place. Why not use what you have? But old ducts are not always a good fit for heat pumps: The wrong-sized ducts can reduce efficiency and lifespan of the system. 

Homeowners often learn during the installation process that the pre-existing ductwork is not the right size for the heat pump. When the ducts are too small, the increased air pressure can back up in the system, straining the blower fan and reducing the system’s efficiency and lifespan. And bigger isn’t always better: If the ducts are oversized, the heat pump won’t work as efficiently, as the system will work harder to deliver the conditioned air.

All of this can lead the equipment to breakdown way sooner than it should. 

5. Old ducts may pose health risks

Another reason older ducts may not be the best pick for your new system? Asbestos. Old ducts have been found to house asbestos, a mineral fiber that was previously used in construction materials for insulation and fire protection. 

While newer ducts are generally safe, it’s still possible for ducts that were installed in the 1980s or earlier to be contaminated with asbestos. This finding makes the idea of relying on vintage ducts seem a lot less rational. 

Mini-splits vs central heat pumps: A final word

The beauty of ductless mini-splits lies in their efficiency. Mini-splits excel in energy conservation and management and they offer more control to every member of the household. All of this adds up to a more comfortable living environment that makes every day at home more enjoyable — plus, reductions on energy use, emissions, and money spent. For the modern homeowner, ductless mini-splits are the clear choice for a healthy, comfortable home.