ductless AC unitOnce you’re convinced that ductless AC units are the right choice to cool your home efficiently, you need to decide how many units your home will need. It all depends on the size of your home, the type of rooms you have, and what kind of zoning you want to achieve. First, you’ll need to understand how much cooling power you’ll need.

What Are Your BTU Needs?

For their ductless air conditioner, Mitsubishi lists the BTU power you’ll need depending on the size of your room or home:

Size of Space BTU
350 sq. feet 9,000 BTU
500 sq. feet 12,000 BTU
750 sq. feet 18,000 BTU
1000 sq. feet 24,000 BTU
1250 sq. feet 30,000 BTU
1500 sq. feet 36,000 BTU

You can have several smaller ductless AC units to meet the BTU demand of your space, or you can have a single large ductless AC unit to meet the overall BTU demand.

The Advantages of Using Multiple Mini-Split AC Units

There are advantages of installing multiple smaller units throughout your home. First, it’s more efficient to only cool the room you’re using. You’ll save money on your power bill that way.

Second, with multiple mini-split AC units, you can divide your home into zones and set a temperature for each. Perhaps you find your living room is always cold, so set the unit in that room to a higher temperature. Or, perhaps you want to be cooler in the bedroom, so set that unit to a lower temperature.

Rooms that May Need Their Own Ductless AC Units

It’s up to you to determine how many units you’ll need, but we find our customers are happiest when they have a separate unit in the room they spend the most time in, whether that’s a home office, living room, or bedroom.

Plus, consider that door positioning can affect the reach of the AC unit. It will cool a room behind a closed door, just slowly. Any large room where you need to keep your door closed should have its own unit. Commonly, rooms with their own ductless AC unit include:

  • Bedrooms
  • Dressing rooms
  • Laundry rooms
  • Sunrooms
  • Man caves

Remember, this unit only needs enough BTU to cool that specific room. Therefore, it will be less expensive than larger units.

It’s also ideal to have a dedicated ductless AC unit in a room that either generates heat or needs to be closely climate controlled to prevent food or other items from melting or spoiling. This might include:

  • Kitchen
  • Wine cellar
  • Storage room
  • Craft room
  • Art room

Don’t Max Out Your Ductless AC System

As you’re planning your zones, remember that it’s best to provide slightly more BTU in the overall system than you’ll need, because there are days when you’ll need more cooling power. For example, days when the temperature exceeds 90 degrees Fahrenheit will require 20 percent more BTU from your system. In the Central Valley, we do reach those temperatures in July and August, even September.

Also, don’t forget to account for ceiling height. If your ceilings are taller than 8 feet, you will need a 20 percent BTU increase. If your ceilings are only higher in the living room, as is common in many homes, you only need the extra capacity in that room.

If you’re not sure how many ductless AC units you’ll need in your home, you should contact us at Irish Heating and Air. We have experience installing these units and know how to fine-tune the zones for your maximum comfort and energy efficiency.