How Many Ductless Units Do I Need?

You’re thinking of getting some ductless mini-split units installed in your home or office, but the question becomes, how many?

Ductless mini-splits provide comfort and cooling to a room, but this option may feel insufficient if you underdo it on your mini-split quantity. You’ll have some cooler rooms and other warmer rooms, and no one wants that.

There are several factors that will play a role in how many ductless mini-splits you should get installed. Let’s talk about these now.


Rooms that are well-insulated can retain the current temperature better. When most people think of insulation, they think of a room keeping heat in. That’s possible, but insulation can also keep the heat out a bit longer than those rooms without insulation.

If certain rooms in your home or office came insulated, or—even better—if the whole building is insulated, then you may not need as many ductless mini-splits.

Unit Type

Another factor that determines how many ductless units you need is the type of mini-split unit you’re working with. Some units include multiple zones or air handling units for inside your home. These indoor units attach to the main unit, which is outside. Thus, if you need to heat something like eight rooms, you’d only need two of these outdoor units.


What kind of weather do you get in your area on average? Is it mostly warm or cooler more often than not? Depending on how you answer that question, you might need more or fewer ductless mini-splits. For instance, if the weather reaches 90 degrees Fahrenheit regularly where you live, then you require roughly 30 percent more BTU (British Thermal Units) per hour than those in homes or offices with lower temperatures.

Height of Your Ceiling

You might think the height of your ceiling doesn’t play a role in determining how many ductless units your home or office requires, but it does. The higher your ceilings, after all, the bigger the room. Thus, you have more cooling needs than the average home or office. Once you have ceilings that exceed eight feet in height, you should get about 20 percent more BTUs compared to homes or offices with lower ceilings.

Square Footage

The primary means of determining how many ductless units you need is to assess the square footage of your home or workplace. Here’s a breakdown of how much cooling you’d have to get in BTUs:

  • 150 - 250 square feet: 6,000 BTUs
  • 250 - 300 square feet: 7,000 BTUs
  • 300 - 350 square feet: 8,000 BTUs
  • 350 - 400 square feet: 9,000 BTUs
  • 400 - 450 square feet: 10,000 BTUs
  • 450 - 500 square feet: 12,000 BTUs
  • 550 - 700 square feet: 14,000 BTUs
  • 700 - 1,000 square feet: 18,000 BTUs
  • 1,000 - 1,200 square feet: 21,000 BTUs
  • 1,200 - 1,400 square feet: 23,000 BTUs
  • 1,500 square feet or more: 24,000 BTUs

Ready to Get Some Ductless Mini-Splits Installed Today? Call PowerSave AC

Whether you’re looking for just a few ductless mini-split systems or more, here at PowerSave AC, we can get you what you need. We sell single-zone through five-zone mini-splits for homes and offices. Get in touch with us today by phone at 855-539-7656.