DIY Expandable Multi-Zone

How to Select Your System (Please read)

If you plan to add an addition to your home, then you have to think longterm. That means buying a Multi-Zone system that lets you expand heating and cooling to that future addition. For typical existing home configurations, MRCOOL can help with this - a single condenser with an open port will do the trick.

There are, however, limitations on the sizing of that additional zone - not every existing home/zone configuration is capable of future expansion on a single condenser system. For such one-offs, you would eventually need two condensers instead of one. For everything else, start by exploring the configurations below. IF your existing zones match those in the products below AND your planned zone is no larger than what that product permits, then that system will work for you.

For each product below, the green on the left represents your existing zones, the yellow on the right represents the max zone or zones you may add.

Don't see your home's configuration below? Send us an email - we can help. CLICK HERE to request help.

This coverage chart will help you determine how many BTUs are required for the space you would like to cool and/or heat, and, therefore, which air handler you should use for each zone (note that the right Condenser/outdoor unit is automatically selected - you don't have to worry about it.). Remember to always round up to the nearest largest size zone for your square footage:

Wall Mount Units

"sf" means Square Feet
  • If your zone is between 180-375 sf, you need a 375 sf Air Handler (9K / 9,000 BTU)
  • If your zone is between 376-500 sf, you need a 500 sf Air Handler (12K / 12,000 BTU)
  • If your zone is between 501-750 sf, you need a 750 sf Air Handler (18K / 18,000 BTU)
  • If your zone is between 751-1,000 sf, you need a 1,000 sf Air Handler (24K / 24,000 BTU)
  • If your zone is between 1,001-1,500 sf, use the 1,500 sf Air Handler (36K / 36,000 BTU)

Ceiling Cassette Units

  • If your zone is between 180-375 sf, you need a 375 sf Air Handler (9K / 9,000 BTU)
  • If your zone is between 376-500 sf, you need a 500 sf Air Handler (12K / 12,000 BTU)
  • If your zone is between 501-750 sf, you need a 750 sf Air Handler (18K / 18,000 BTU)
  • 751-1,000 Square Feet (sf) - Not Available
  • 1,001-1,500 Square Feet (sf) - Not Available

Note: The product configurations below work with all your existing zones, and they ensure that when the future zone is added, even if all indoor units (air handlers) were to run simultaneously, their combined BTU output would not exceed the BTU rating of the outdoor unit (condenser).

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