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MrCool DIY 5th Gen 18K Multi-Zone Condenser (3 zones)
MrCool · DIY 5th Gen Multi-Zone

MrCool DIY 5th Gen 18K Multi-Zone Condenser (3 zones)

Model DIY-MULTI3-18HP230D-O

SCORE6.3 / 10

The small 5th Gen condenser, up to three heads with the new 6K units: 13,300 Btu/h at 5°F total. For two rooms, two single-zone units give more heat.

Specs

SpecMrCool DIY 5th Gen 18K Multi-Zone Condenser (3 zones)
Nominal size18,000 BTU
Voltage230V
Rated heat at 47°F18,000 BTU/h
Heat at 17°F13,400 BTU/h
Heat at 5°F13,300 BTU/h
Lowest heating temp-13°F
Max heat at lowest temp7,000 BTU/h
SEER223.9
HSPF2 (Region IV)10
Install typeQuick-connect
Line set in box25 ft
Max line run75 ft
Warranty covers owner installYes
Warranty, parts5 yr
Warranty, compressor7 yr
ENERGY STAR Cold ClimateYes
ENERGY STARYes
RefrigerantR-454B
ZonesUp to 3 indoor units
Minimum heat output at 47°F5,700 Btu/h (whole system)
Electrical208/230V; 16 A MCA, 20 A max breaker
Line limits75 ft per head, 172 ft total, 33 ft height indoor to outdoor

Sources: NEEP ccASHP list · MRCOOL DIY 5th Gen multi-zone install manual · MRCOOL DIY 5th Gen multi-zone service manual (Apr 20, 2026) · MRCOOL DIY 5th Gen limited warranty (rev. 07.03.25)

Before you buy

  • The 4th Gen multi-zone (C suffix, R-410A) is a different system; its 18K ran two zones, not three.
  • On earlier generations owners report idle heads still heating or cooling and rooms overshooting setpoint; there is no long 5th Gen record yet.
  • Line sets are one-time installs; runs past the standard 24.6 ft per head and ducted (AHU) air handlers call for added refrigerant per the manual.
  • Sold on Amazon by a third-party seller in small quantities; condenser only, heads and line sets sold separately.

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