4-Zone MRCOOL DIY Mini Split Systems (5th Generation)

Cover up to four rooms or zones with a single outdoor condenser using MRCOOL’s 5th Generation DIY multi-zone systems. Each 4-zone package includes pre-charged R454B line sets and Quick-Connect fittings so you never handle refrigerant.

Our 4-zone MRCOOL DIY mini split systems are ideal for whole-floor and whole-home projects where you want true room-by-room control without the cost and complexity of traditional ductwork. Each system includes four indoor air handlers—choose wall mounts, ceiling cassettes, or a mix of both—plus a matching outdoor condenser and factory pre-charged R454B line sets. Installation is designed for serious DIYers: no vacuum pump, no gauges, and no EPA certification required.

A 4-zone MRCOOL setup can easily handle multiple bedrooms, a living room, home office, bonus room, or finished basement on the same system. Every zone gets its own thermostat and remote or app control, so you can fine-tune comfort, reduce energy waste, and avoid fighting over a single central thermostat.

Quick Answers

  • DIY-ready? Yes — condensers, air handlers, and line sets are all pre-charged with R454B and use MRCOOL Quick-Connect fittings.
  • Indoor unit options? Configure four wall mounts, four ceiling cassettes, or any mix of wall and cassette heads to match your floor plan.
  • Need help planning a 4-zone layout? Use our Custom Multi-Zone Builder or email sales@mrcooldiydirect.com for help sizing and selecting a system.

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Prefer Professional Install Equipment?

Check Out the MRCOOL® Olympus Series

If you’d rather use contractor-grade, non-DIY MRCOOL equipment installed by a licensed pro, our Olympus Series systems are built for traditional professional installation and high-performance comfort.

  • Pro-grade MRCOOL® ductless & ducted systems
  • Perfect for contractors, builders & full-service installs
  • Great option when DIY isn’t the right fit
Want a pro-installed solution instead?
Explore Olympus Pro Systems
Ideal when you plan to work with a local HVAC contractor.

4-Zone MRCOOL DIY Mini Split FAQ

What is a 4-zone MRCOOL DIY mini split system?

A 4-zone MRCOOL DIY mini split system allows you to heat and cool up to four separate rooms or zones from a single outdoor condenser. Each system includes four indoor air handlers—wall mounts, ceiling cassettes, or a mix of both—plus factory pre-charged R454B Quick-Connect line sets so homeowners can install the system without handling refrigerant.

Do I need an HVAC license to install a 4-zone MRCOOL DIY system?

No. MRCOOL DIY systems are designed for homeowners and use pre-charged R454B line sets with Quick-Connect fittings. No EPA license, vacuum pump, or refrigerant gauges are required to install a 4-zone MRCOOL DIY system.

Can I mix wall-mounted air handlers and ceiling cassettes in a 4-zone configuration?

Yes. MRCOOL 5th Generation multi-zone condensers fully support mixing indoor unit types. You can combine any mix of wall mounts and ceiling cassettes across all four zones to match your room layout and comfort needs.

Is a 4-zone MRCOOL DIY system good for whole-home use?

Many homeowners use a 4-zone system to condition a full floor or most of a single-story home. With the right BTU combinations, a 4-zone MRCOOL DIY setup can cover multiple bedrooms, a living room, home office, and bonus room. Very large or complex layouts may require additional zones or a professionally engineered solution.

What BTU sizes should I choose for a 4-zone MRCOOL system?

Common 4-zone layouts include 9k BTU air handlers for standard bedrooms, 12k–18k BTU units for living areas or kitchens, and 18k–24k BTU units for larger spaces or insulated garages. The best mix depends on square footage, ceiling height, insulation, and climate. Use the MRCOOL DIY Direct Custom Multi-Zone Builder for accurate configuration help.

How long can MRCOOL DIY line sets be in a 4-zone system?

MRCOOL DIY Quick-Connect line sets come in 16, 25, 35, and 50 foot lengths. Most 4-zone condensers allow extensions and generous total line length, giving you flexibility when placing indoor units throughout the home. Always confirm maximum line lengths for your specific condenser model.

Can a 4-zone MRCOOL system heat effectively in cold climates?

Yes. MRCOOL 5th Generation Hyper Heat systems provide strong low-ambient performance, with many models heating efficiently down to -13°F. Check the performance tables for your specific model to confirm cold-weather heating capabilities.

Where can I get help designing or sizing a 4-zone MRCOOL system?

Use the Multi-Zone Builder at https://mrcooldiydirect.com/pages/build-your-customized-mini-split , or email MRCOOL DIY Direct support at sales@mrcooldiydirect.com for personalized sizing and layout guidance.