18,000 BTU heat pump

MRCOOL 18,000 BTU Wall-Mount

Name: MRCOOL 18,000 BTU Wall-Mount
Brand: MRCOOL

Model #: O-HH-18-HP-C-230C-O / O-18-HP-WMAH-230C-O

Every spec on this page comes from an official certification record or a cited manufacturer document. The source is linked next to each value.

MRCOOLO-HHMini-split heat pump

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Check model number O-HH-18-HP-C-230C-O / O-18-HP-WMAH-230C-O at your preferred retailer.

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Decision guide

What the published numbers mean before you compare every spec.

18,000 BTU is closest to ENERGY STAR’s 700–1000 sq. ft. room-size row.

At 5°F, certified output is 18,000 BTU/h — 100% of its 47°F rating.

The cited fields do not confirm a pre-charged line set or DIY-line designation for this model.

Voltage is not published in the sources we cite, so confirm it before choosing equipment.

HSPF2 11 is above the 10.2 average among 125 models in the same rounded capacity class.

Your room is near 700–1000 sq. ft. under the ENERGY STAR starting-point assumptions, and a load calculation agrees.

You have not confirmed the voltage, room load, and installation requirements for this exact model.

Room guidance is a screening estimate for standard conditions. Check your room inputs; use Manual J for final sizing.

Outdoor model number	O-HH-18-HP-C-230C-OSource: ENERGY STAR Mini-Split Heat Pumps dataset · 2026-07-23
Indoor model number	O-18-HP-WMAH-230C-OSource: ENERGY STAR Mini-Split Heat Pumps dataset · 2026-07-23
AHRI reference number	216032563Source: ENERGY STAR Mini-Split Heat Pumps dataset · 2026-07-23
Series	O-HHSource: ENERGY STAR Mini-Split Heat Pumps dataset · 2026-07-23
Heating capacity at 47F	18,000 BTU/hSource: ENERGY STAR Mini-Split Heat Pumps dataset · 2026-07-23
Heating capacity at 17F	18,000 BTU/hSource: ENERGY STAR Mini-Split Heat Pumps dataset · 2026-07-23
Heating capacity at 5F	18,000 BTU/hSource: ENERGY STAR Mini-Split Heat Pumps dataset · 2026-07-23
SEER2	21.4Source: ENERGY STAR Mini-Split Heat Pumps dataset · 2026-07-23
EER2	12.5Source: ENERGY STAR Mini-Split Heat Pumps dataset · 2026-07-23
HSPF2	11Source: ENERGY STAR Mini-Split Heat Pumps dataset · 2026-07-23

Values marked ENERGY STAR come from the certification dataset; values marked Manufacturer spec come from the linked product documents.

The sources we cite do not publish these values for this model, so we leave them blank rather than guess.

VoltageMinimum circuit ampacityMaximum breaker / fuseLine set length rangePre-charged line setBrand DIY line

Room-size guidance is a starting point, not a load calculation. Confirm sizing and installation requirements with a qualified contractor.