MRCOOL® Olympus E Star® 4th Gen 18,000 BTU (1.5 Ton) Ductless Mini Split Heat Pump — O-ES-18-HP-C-230C-O1 + O-18-HP-WMAH-230C-O
Overview
The MRCOOL® Olympus E Star® 4th Gen 18k is a single-zone ductless mini split heat pump designed for professional HVAC installation. It pairs a wall-mounted air handler with a compact inverter-driven condenser for consistent comfort, quiet operation, and strong efficiency. Control is simple with the included remote and built-in Wi-Fi via the MRCOOL® Smart HVAC app, plus voice control compatibility with Amazon Alexa and Google Assistant. The outdoor unit features Gold Fin® corrosion protection and the system uses R-454B refrigerant.
Data provided includes two different SEER2 values for this size (23.5 and 21.4). This page uses the rating shown for the condenser pairing: Up to 21.4 SEER2.
Highlights
- Efficiency: Up to 21.4 SEER2 and up to 12.5 EER2 with inverter performance.
- Cold-climate capable: Outdoor operation listed down to -22°F for heating (and cooling).
- Gold Fin® condenser: Corrosion-resistant protection for harsh or coastal environments.
- Smart control included: Built-in Wi-Fi + Smart HVAC app; works with Alexa/Google Assistant.
- Comfort features: Sleep mode, louver memory, auto-restart, fan-only operation.
- Designed for pros: Professional installation required for optimal performance and warranty support.
501–750 sq ft*
18,000 / 18,000 BTU
98.4 ft
Outdoor 59 dB(A)
*Other fields list “Up to 800 sq ft.” Real coverage varies by climate, insulation, and room load.
What’s Included
- Outdoor Condenser: O-ES-18-HP-C-230C-O1
- Wall-Mounted Air Handler: O-18-HP-WMAH-230C-O
- SmartHVAC WiFi control (app + voice control supported)
- Remote control
- Installation and service documentation (see Documents & Downloads)
Indoor Specs
Model: O-18-HP-WMAH-230C-O (Wall-Mounted Air Handler)
| Brand / Series | MRCOOL • Olympus 4th Gen Air Handlers |
| Type | Mini-Split (Indoor Unit) |
| Max Coverage | Up to 800 sq ft |
| Indoor Noise (multi-speed) | 49.5 / 45 / 38 / 31.5 / 19.5 dB(A) |
| Speeds / Oscillation | 5 (Variable) • Oscillation: Yes |
| Refrigerant | R-454B |
| Line Set Fittings | Flare • Liquid 1/4" • Suction 1/2" |
| Electrical | 208–230V • 1-Phase • 60 Hz • Max Breaker 15A |
| Mount / Color | Wall • White |
| Filter | Reusable |
| Dimensions (W×D×H) | 40.31" × 9.69" × 12.64" |
| Weight | 27.34 lb |
| Control Options | Smart HVAC app • Remote included • Works with iOS/Android • Alexa/Google Assistant |
| Aux Heat | Not available on this air handler (no aux heater) |
| Restrictions | Restricted states: GU, PR, VI • Proposition 65: Yes |
Outdoor Specs
Model: O-ES-18-HP-C-230C-O1 (Single-Zone Condenser)
| Brand / Series | MRCOOL • Olympus 4th Gen Single-Zone Condensers |
| Cooling / Heating Capacity | 18,000 BTU / 18,000 BTU |
| Outdoor Temp Range (Cooling) | -22°F to 122°F |
| Outdoor Temp Range (Heating) | -22°F to 75°F |
| Efficiency | SEER2: Up to 21.4 • EER2: Up to 12.5 • HSPF2-4: 11 • HSPF2-5: 8.5 |
| Outdoor Noise | 59 dB(A) |
| Electrical | 208–230V • 1-Phase • 60 Hz • Max Breaker 20A • MCA 19A |
| Refrigerant | R-454B • 55.38 oz |
| Line Set | Flare • Liquid 1/4" • Suction 1/2" • Max length 98.4 ft |
| Inverter / Metering | DC inverter • Metering: EXV + Throttle Valve |
| Compressor | Rotary |
| Dimensions (W×D×H) | 35.04" × 13.46" × 26.5" |
| Weight | 99.87 lb |
| Certifications | ENERGY STAR® • UL Listed • CSA Listed • ETL Listed • AHRI Certified |
| Restrictions | Restricted states: GU, PR, VI • Proposition 65: Yes |
Documents & Downloads
Outdoor Condenser: O-ES-18-HP-C-230C-O1
Indoor Air Handler: O-18-HP-WMAH-230C-O
Note: Some documents apply to the Olympus 4th Gen single-zone platform and may be shared across multiple sizes.
Important
- HVAC technician required: Installation by a licensed professional is required where applicable.
- Refrigerant and piping: R-454B refrigerant with flared connections (1/4" liquid, 1/2" suction).
- Line length: Max line set length is 98.4 ft. Longer runs can reduce performance and may require design adjustments.
- Electrical: Outdoor unit requires up to a 20A breaker (MCA 19A).
- Warranty basics: 5-year parts / 7-year compressor (with notes about extended coverage upon registration as provided).
FAQs
Is professional installation required?
Yes. This system is intended for installation by a licensed HVAC technician.
What size space does this cover?
Provided specs list coverage as 501–750 sq ft and also “up to 800 sq ft.” Actual results vary by climate and building load.
Does it support app and voice control?
Yes. Wi-Fi connectivity supports the MRCOOL Smart HVAC app and voice control via Amazon Alexa and Google Assistant.
What line sizes does it use?
Flared connections with 1/4" liquid and 1/2" suction lines.
What electrical circuit is required?
208–230V, 1-phase, 60 Hz. Outdoor unit: 20A max breaker and 19A MCA.
