Frequently asked questions

What size MRCOOL mini split do I need?

As a general guideline, allow approximately 20–25 BTUs per square foot of conditioned space.

  • 6,000 BTU: 100–250 sq. ft.
  • 9,000 BTU: 250–400 sq. ft.
  • 12,000 BTU: 400–550 sq. ft.
  • 18,000 BTU: 550–800 sq. ft.
  • 24,000 BTU: 800–1,050 sq. ft.
  • 36,000 BTU: 1,050–1,500 sq. ft.

    ***Actual sizing depends on insulation, ceiling height, windows, sun exposure, and climate.
How cold can the MRCOOL DIY 5th Gen operate?

The MRCOOL DIY 5th Gen provides reliable heating in outdoor temperatures as low as -13°F, making it an excellent solution for year-round comfort in many climates.

What is included with the MRCOOL DIY system?


Each MRCOOL DIY system includes everything needed for a standard installation, including the indoor air handler, outdoor condenser, pre-charged Quick Connect® line set, communication cable, remote control, drain hose, wall sleeve, wall template, and mounting hardware. You'll only need common tools such as a drill, level, and basic hand tools.

Can I install the system myself?


Yes. MRCOOL DIY systems are designed for homeowners and do not require specialized HVAC tools or vacuum pumps. Simply mount the indoor and outdoor units, route the pre-charged line set through a 3.5-inch wall opening, connect the Quick Connect® fittings, attach the communication cable, and restore power. Step-by-step installation videos are also available on YouTube.

Can I use a longer or shorter line set?


Yes. MRCOOL DIY systems support multiple line set lengths depending on the model. If you need a longer run, compatible extension line sets and coupler kits are available. Depending on the system, the maximum supported length can be up to 66 ft or 75 ft.

How do I choose the correct line set length?


Measure the actual route from the outdoor condenser to the indoor air handler, including all turns and bends—not just the straight-line distance. Choose the next available line set length if your measurement falls between sizes. Any excess line should be neatly coiled according to the installation instructions.

What's the difference between the DIY 5th Gen, DIY Select, and Easy Pro?

All three systems are designed for DIY installation using MRCOOL's pre-charged Quick Connect® line sets, but they differ in included line set length, features, efficiency ratings (SEER2 Rating) and warranty coverage.

DIY 5th Gen

  • Premium DIY model with the most advanced features
  • Includes a 25 ft pre-charged Quick Connect® line set
  • Higher SEER2 efficiency
  • Enhanced cold-weather heating performance
  • Advanced Wi-Fi and smart home compatibility
  • 5-Year Parts Warranty
  • 7-Year Compressor Warranty

DIY Select (Newest Model)

  • Newest addition to the MRCOOL DIY lineup
  • Includes an 11.5 ft pre-charged Quick Connect® line set
  • Available in White or Black indoor air handler finishes (model dependent)
  • Designed for quick and easy DIY installation
  • Compatible with additional line set lengths and extensions when needed
  • 1-Year Parts Warranty
  • 2-Year Compressor Warranty

Easy Pro 5th Gen

  • Budget-friendly DIY system for straightforward installations
  • Includes an 11.5 ft pre-charged Quick Connect® line set
  • Compact, simplified design
  • Ideal for shorter line set runs
  • 1-Year Parts Warranty
  • 2-Year Compressor Warranty
What's new in the MRCOOL DIY 5th Gen?

Compared to the previous generation, the DIY 5th Gen offers higher SEER2 efficiency, quieter operation, enhanced cold-weather heating performance, upgraded smart controls, and uses the newer environmentally friendly R-454B refrigerant.

What’s the warranty for the DIY 5th gen?


MRCOOL DIY 5th Gen systems include:

5-Year Parts Warranty
7-Year Compressor Warranty

Warranty registration is recommended after installation to receive full coverage. You can register for your warranty here.

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