How To Calculate Your Ductless Mini Split System

How To Calculate Your Ductless Mini Split System

Gene B |


Here are three ways you can get help choosing a minisplit system for your space:

  1. You can get live help by calling us now. No pressure. We honestly love talking about this stuff.
  2. You can use our minisplit calculator to determine your perfect setup.
  3. You can read through the article below and let that guide your way.

Calculating Your Ductless Mini Split System

1. Determine Placement & Lineset Lengths

Outdoor Condenser Placement:

  • Location: Choose a location for the outdoor condenser. Ensure it's accessible for electricity via an outdoor disconnect.
  • Mounting: Decide whether to place the condenser on a ground pad or mount it to the wall.

Indoor Air Handlers:

  • Type: Choose between ceiling or wall-mounted air handlers.
  • Location: Preferably mount air handlers on an interior side of an exterior wall to allow condensate line to gravity drain. If mounting on an interior wall, a condensate pump will be necessary. Ceiling mounts come with a built-in pump.
  • Lineset Lengths: Linesets carry refrigerant from the condenser to the air handlers. Be sure to measure the required lineset lengths carefully. Getting too short of a line set for your system can be a costly mistake. Use single linesets when possible for maximum performance (use a single 35' lineset rather than coupling two 16' linesets, for instance). For lengths over 50' you'll need to couple two linesets (a 50' and a 25' will give you 75' of coverage, for instance). No matter the length, do not couple the communication wire. You must use only one communication wire between the condenser to the air handler to avoid risk of voiding the manufacturer warranty. Minimum lineset length is 16 feet, and the maximum is 75 feet per line, with a total of up to 225 feet in multi-zone systems.
  • Protection: Cover your linesets with LineGuard to prevent insulation deterioration and enhance system efficiency.

2. Determine the System Size

Room Calculation:

  • Number of Rooms/Zones: Identify how many areas you want to condition.
  • Square Footage: Calculate the square footage of each room/zone. For rooms with ceilings over 8 feet, add 12.5% more square footage for each additional foot of height.
  • System Matching: Choose air handlers based on the calculated size per room/zone and ensure the condenser matches the total required BTUs. Remember, a condenser can manage up to 5 rooms/zones in a multi-zone system and can only output the BTUs it's rated for, regardless of the rating of the air handlers.

Final Thoughts:

Installing the right mini split system is crucial for efficient heating and cooling. Don't hesitate to reach out if you have questions or want more help or to use our online calculator to build the perfect system for your home. We want to be sure you have the support you need to build the perfect system for your space.

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