Multi-Zone System Builder

One outdoor unit, a separate air handler for every room. Pick your parts — we check that the combination is supported and total it up.

1Choose the system

MRCOOL DIY 5th Gen Multi-ZoneR-454B refrigerant · pre-charged quick-connect line sets · 208/230VMRCOOL DIY 4th Gen Multi-ZoneR-410A refrigerant · pre-charged quick-connect line sets · 208/230V

2Choose the outdoor condenser

Bigger condensers run more zones. Total the BTUs of the rooms you want to cool — the calculator can size each room.

3Add an air handler for each zone

Each zone needs one indoor air handler and one pre-charged line set to reach the condenser.

How multi-zone sizing works

Every condenser supports a specific set of air-handler combinations. The builder only marks a system valid when the manufacturer lists that exact combination.
You don't have to use every port: a 5-zone condenser can run 2, 3 or 4 air handlers.
Wall-mount air handlers are the standard choice; ceiling cassettes sit flush in the ceiling between joists.
DIY systems use pre-charged quick-connect line sets — no vacuum pump or gauges. Choose the length that reaches from each air handler to the condenser.