System Builder

Build your multi-zone system.

Four steps: size your rooms, pick an MRCOOL-approved condenser, choose air handlers, then your copper.

Add each room you want to heat and cool. One room gets a single-zone kit; two to six rooms get a multi-zone system. We size each room from MRCOOL's coverage ratings.

Ceiling height
Climate

We've pre-filled the size for each room. Change a size or style if you like — we'll keep checking it against MRCOOL's matchups.

Got ductwork in part of the house? Pick Ducted for that zone: a DIY® Hybrid™ air handler (24K or 36K) runs on your existing ducts alongside the other zones. One per system, on the 36K 5-zone, 48K or 55K condenser.

Pre-charged Quick Connect® line sets, sized to each air handler. Measure the run from the indoor unit to the condenser and round up.

Total line length: 0 ft

Optional add-ons that make the install cleaner and last longer. Tap to add.

You'll also need (not sold here)
  • Outdoor service disconnect — a weatherproof shut-off within sight of the condenser. Required by code in most areas.
  • Electrical whip — the flexible conduit that runs power from the disconnect to the condenser.
Pick these up at a local supply house, or have your electrician bring them.

Here's everything in your build. Tap any item to see its full specs.

Browse the full catalog
24K MRCOOL® DIY Hybrid™ Air Handler Have ductwork in part of the house? Mix a ducted air handler into your multi-zone.A DIY® Hybrid air handler runs on your existing ducts and pairs with the 36K 5-zone, 48K and 55K multi-zone condensers, alongside wall units for rooms the ducts don't reach. See ducted options
Or shop individual components

Multi-Zone Systems

Everything you need for a multi-zone mini-split system — heat and cool multiple rooms from a single outdoor condenser. Browse our selection of multi-zone condensers and compatible indoor air handlers and ceiling cassettes.

  • Multi-zone condensers available in 3, 4, 5, and 6 zone configurations
  • Compatible air handlers in 6K, 9K, 12K, and 18K BTU
  • OuttaSight® ceiling cassettes for a sleek, hidden installation
  • All DIY 5th Generation for easy, tool-free setup
14 products
Buying guide

How to plan a multi-zone mini split

A multi-zone system runs two to six indoor units from one outdoor condenser, and each room keeps its own temperature. It means one condenser on the side of the house and one 230V circuit instead of a row of outdoor units, and for three or more rooms it usually costs less than buying single-zone systems.

Size each room first. Use the same square-footage guide as a single-zone system: 6K or 9K for most bedrooms, 12K for larger bedrooms and offices, 18K–24K for living areas. Then choose a condenser MRCOOL approves for that exact mix. The approved list is built into our system builder, so it won't offer a mismatch.

Choose indoor units. Mix wall-mount air handlers, OuttaSight® ceiling cassettes and, on approved condensers, a DIY® Hybrid™ ducted air handler that uses your existing ductwork.

Plan the extras. Each indoor unit needs its own pre-charged line set. The condenser needs a dedicated 230V circuit, disconnect and whip installed by a qualified electrician, plus a pad or wall bracket. The multi-zone guide has example builds and prices.

Questions

Multi-zone FAQ

How many indoor units do I need?

At least two, and up to six depending on the condenser: 3-zone, 4-zone, 5-zone or 6-zone.

Can I add a room later?

Yes, if the condenser has a free port and MRCOOL approves the new mix. Check it in the system builder before you buy.

Is multi-zone 115V or 230V?

230V. Every DIY® 5th Gen multi-zone condenser needs a dedicated 230V circuit sized from its nameplate by a qualified electrician.

Do I need a vacuum pump?

No. DIY® line sets are pre-charged with Quick Connect® fittings. Here's how they work.