The quest to rule the thermostat

A house with central heating is a house where no one gets what they want. The living room might be an icebox—but cranking up the heat turns an upstairs bedroom into a sauna. A room with a picture window is a greenhouse for a few hours, then cold enough to call for mittens indoors for the rest of the day. The quest for comfort can turn family against family, as each member struggles to control the thermostat to suit their own needs. 

In which good design is its own superpower

A room-by-room heat pump system (aka a “ductless mini split”) changes all of that—it gives everyone in a household the ability to control the climate of the room they happen to be in. This superpower directly stems from its design. Unlike a conventional ducted system, which has one big fan that pushes air through a network of ducts connected to a heater or air conditioner, a ductless mini split system divides that work between a heat pump outside your home and an array of small, hyper-efficient indoor air handling units—each with its own fan and temperature controls. 

A house divided is a pretty great house, actually

Room-by-room control can bring peace to a divided household. That one family member who is only happy when the thermostat is set to over 70 degrees can read a book in the living room in balmy splendor, while the one who needs to keep the temperature below 65 in order to fall asleep can sleep soundly in the upstairs bedroom. With room-by-room control, each room can be the perfect temperature whenever you're in it.

But there are other benefits too. The freedom to set each room to a different temperature also means that your house has none of the hot or cold areas that form in homes with old fashioned, centralized heating. 

Room-by-room climate control also changes the temperature of each individual room—and by extension, your home—much more quickly. Shifting the temperature of an entire house with an old-fashioned ducted system takes so long that it’s standard practice to keep that system running all day, and to do things like crank up the heating or air conditioning in hopes of reaching a desired temperature faster. The ability to shift the temperature in a room lighting-fast, instead of the hours that it can take with an old-fashioned forced air system, means it’s not necessary to keep the thermostat on all day long in order to feel comfortable in your own home. 

Ductless climate control also has real financial benefits. Many homes have two discrete systems for heating and cooling, while room-by-room climate control systems can do both. If you’re building a new home, an addition, or an ADU, it can also be easier and less expensive to install a heat pump than a ducted system—and it takes up less space. It’s not unusual for air ducts to be a foot in diameter, while the conduits for a heat pump are a fraction of that. It’s 30 percent more efficient (and much less expensive) to heat and cool a home room-by-room, in part because the air ducts that are used to move hot or cold air through a house are often leaky and poorly insulated. Air has many fine qualities, but heating it up, then blowing it through an entire house with a ducted system is extravagantly wasteful (and expensive) in comparison. 

The room-by-room comfort that a ductless heat pump provides might seem like a luxury, but in reality, it’s one of the most practical home purchases that you can make. It’s a way to live in comfort, but also lower your utility bill. It’s a tool for navigating cold fronts, heat waves, and other extreme weather, but also for each member of your family living in their own ideal microclimate. It’s your own personal example of the second law of thermodynamics in action, but it’s also pure magic.

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