OLMO Sierra 18,000 BTU Outdoor Condenser, 230V, R454B - Mini Split Air Conditioner Heat Pump

Name: OLMO Sierra 18,000 BTU Outdoor Condenser, 230V, R454B - Mini Split Air
Brand: OLMO
SKU: OS-RMS18-230VO
Price: 1048.95 USD
Availability: InStock

OLMO Sierra series 18k BTU R454B outdoor unit with grille and fan

OLMO5-Yr Warranty

OS-RMS18-230VO

Product specifications

Brand	Olmo
Voltage	230V
SEER	22
WiFi	Not Included
Type	Outdoor Unit
Freon	R454B
Compressor	Inverter

~~$1,165.50~~ $1,048.95 Save 10%

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Product variants

⛔ Wait! This is an Individual Component To build a working system, this unit must match your other equipment in two ways:

Same Brand Only: Only pair with other same Brand and Series.
Same Refrigerant: Both units must use the exact same gas type (R454B, R32, or R410A).

Mixing different brands or refrigerant types will cause the system to fail and void your warranty.

Quantity

Pickup available at 3550 Northwest 113th Court

Usually ready in 2-4 days

Questions about this system?

Answers in seconds — tap a question below

Sized for about 500–800 sq ft. Rule of thumb: ~20 BTU per sq ft, and 12,000 BTU = 1 ton (this unit is 18,000 BTU (1.5-ton)). Ceiling height, insulation, sun and climate shift that — if you're between sizes, size up for hot/humid rooms. Not sure? We'll confirm the right BTU for your space.
12,000 BTU = 1 ton — "tons" is just the older way of stating capacity. So 24,000 BTU = 2 tons, 36,000 = 3 tons, and so on. This system is 18,000 BTU (1.5-ton). BTU tells you the capacity; SEER2 tells you the efficiency.
It uses R454B — the newest low-GWP eco refrigerant, so it's future-proof and efficient. The outdoor unit ships pre-charged for a standard line set, so most installs need no extra refrigerant; your licensed, EPA-608-certified installer verifies the charge and tops it off if your line set is longer.
Rated SEER2 22.0 — a strong efficiency number, and the higher it is the lower your energy bills. Its inverter compressor ramps up and down instead of cycling on/off, so it holds the temperature steadily, runs quietly, and uses less power than a standard AC or window unit.
Needs a dedicated 230V circuit, like a large household appliance, so it can deliver full capacity to larger rooms and multi-zone setups. Your licensed HVAC installer or electrician sets up the correct breaker and disconnect to meet local electrical code.
Yes — a big upgrade. It's far more efficient (inverter, SEER2 22.0) and much quieter, since the compressor sits outside instead of in your window or on the floor. It mounts permanently, doesn't block a window, and heats as well as cools year-round. Higher upfront cost, but lower bills and a longer lifespan.
Yes to all three. It's an inverter heat pump — cools in summer, heats in winter (even in the cold), far more efficiently than electric heaters. A Dry mode also pulls out humidity, so rooms feel cooler and less muggy.
Yes — WiFi is not included, so you can set schedules, change the temperature, and even turn it on before you get home, all from the mobile app (and pair it with voice assistants). A standard remote is included too.
Ships as a complete set: OS-RMS18-230VO. Everything arrives together — check the photos and specs for the full kit.
It should be installed by a licensed, EPA-608-certified HVAC professional — we don't recommend DIY installation. Handling refrigerant requires EPA Section 608 certification under U.S. law, and professional installation keeps the system safe, code-compliant, and your manufacturer warranty valid.
Yes — you get full inverter heat-pump technology and the same core features as premium brands without paying for the name, which is how we keep prices low. Shipping is free on U.S. orders over $300, and our team can help with sizing and support.

Free Shipping over $300Ships free to the lower 48 states — flat rate, no surprises at checkout.
USA-Based Expert SupportReal U.S. HVAC pros help with BTU sizing, refrigerant and install questions.
Genuine Units & Full WarrantyBrand-new, authorized-dealer equipment backed by the full manufacturer warranty.
Fast Nationwide ShippingIn stock and ready to ship from U.S. warehouses across all 48 states.

What Stands Out

Sleek Wall-Mount Design

A slim, quiet indoor head mounts high on the wall and delivers 18000 BTU of heating & cooling — modern looks with whisper-quiet operation.

Inverter Efficiency — SEER2 22

A variable-speed inverter compressor ramps to match the load instead of cycling on/off, holding SEER2 22 on 230V — steady comfort with noticeably lower energy bills.

Right-Sized Coverage

Engineered to heat & cool up to 500–800 sq ft — matched capacity so you never over- or under-size the space.

Sierra Wall Mount

OLMO's Multi-Zone Sierra Series is a versatile HVAC solution that provides efficient heating and cooling for multiple rooms, featuring advanced inverter technology for precise temperature control and significant energy savings. Using eco-friendly R410A refrigerant, the system delivers reliable performance with minimal environmental impact. Ideal for both residential and commercial applications, the Sierra Series combines quiet operation, flexible installation, and user-friendly controls, making it a perfect choice for maintaining year-round comfort across multiple zones with one efficient system.

Warranty and Tech Support Info

By selecting OLMO products for your home or business, you’ll receive expert technical support from heating and cooling specialist, including access to product manuals, troubleshooting guides and warranty information.

The manufacturer provides a Limited Warranty of 5 years for the compressor and 2 years for parts.

Warranty terms

White wall-mounted air conditioner with sleek design and modern aesthetic.

Main Features

OLMO's Multi-Zone Sierra Series delivers efficient multi-room comfort with advanced inverter technology for precise temperature control. Its eco-friendly R454B refrigerant reduces environmental impact, while quiet operation ensures minimal disruption. With flexible installation options, sleek design, and reliable heating and cooling, it’s the perfect solution for modern multi-zone climate control needs.

Technical Specifications

Indoor Models	OS-RM09SW-230VI	OS-RM12SW-230VI	OS-RM18SW-230VI	OS-RM24SW-230VI
Power Supply (V-Ph-Hz)	208/230V-1Ph-60	208/230V-1Ph-60	208/230V-1Ph-60	208/230V-1Ph-60
Cooling Capacity (Btu/h)	9000	12000	18000	23400
Heating Rated Capacity (Btu/h)	9500	13000	19000	26000
Output Power (W)	25	25	35	35
Rated Current (A)	0.11	0.11	0.17	0.17
Indoor Air Flow (CFM)	341	365	647	706
Indoor Noise Level (Hi/Mi/Lo) (dB(A))	39/35/30	39/35/30	45/41/37	47/45/42
Net Dimensions (WxHxD) (in)	32.02x10.75x8.13	37.38x10.75x8.13	48x12.63x9.25	48x12.63x9.25
Packing (WxHxD) (in)	39.38x13.19x6.38	39.38x13.19x6.38	51.75x15.44x12.50	51.75x15.44x12.50
Net/Gross Weight (lbs)	19.84 / 24.25	19.84 / 24.25	31.97 / 37.48	31.97 / 37.48
Refrigerant Piping (Liquid Side / Gas Side) (in)	1/4" / 3/8"	1/4" / 3/8"	1/4" / 1/2"	3/8" / 5/8"

Outdoor Models	OS-RMS18-230VO	OS-RMS24-230VO	OS-RMS36-230VO	OS-RMS42-230VO
Power Supply (V-Ph-Hz)	208/230V-1Ph-60	208/230V-1Ph-60	208/230V-1Ph-60	208/230V-1Ph-60
Cooling Capacity (Btu/h)	18000	27000	36000	42000
EER2	13.33	12.85	12.85	12.0
SEER2	22.0	23.0	22.0	22.0
Heating Rated Capacity (Btu/h)	18000	27000	36000	36000
HSPF2	10.0	10.0	10.0	9.5
COP2 (W/W)	3.82	3.60	3.91	3.60
Max Fuse (A)	30	40	50	60
Outdoor Air Flow (Hi) (CFM)	1850	3357	3357	3357
Outdoor Side Noise Level (dB(A))	55	62	64	64
Dimensions (WxHxD) (in)	33.88x26.38x12.25	38.38x32.88x14.12	38.38x32.88x14.12	38.38x32.88x14.12
Outdoor Unit Packing (WxHxD) (in)	39x28.75x17.75	43.75x37.75x18.12	43.75x37.75x18.12	43.75x37.75x18.12
Net/Gross Weight (lbs)	101.4/112.4	160.6/183.2	169.8/191.8	172/194
Refrigerant Type/Quantity (oz)	R454B/51.15	R454B/76.2	R454B/105.8	R454B/105.8
Refrigerant Piping (Liquid Side / Gas Side) (in)	1/4" / 3/8"	1/4" / 3/8"	1/4" / 3/8"	1/4" / 3/8"
Max Refrigerant Pipe Length Each/Total (ft)	82/164	82/230	82/230	82/262
Ambient Outdoor (Cooling) (°F)	5~125	5~125	5~125	5~125
Ambient Outdoor (Heating) (°F)	-13~75	-13~75	-13~75	4~75

Multiple Control Methods

Olmo’s Multi-Zone Sierra Series can be managed with a user-friendly remote control and the. This options offer precise temperature adjustments and optimal climate control for ultimate convenience.

Frequently Asked Questions

What size mini split do I need for my home?

For effective cooling and heating, the Olmo Sierra 18,000 BTU unit is suitable for spaces up to 850 square feet. This capacity makes it ideal for medium-sized rooms or open areas.

Can I install a mini split myself?

While some homeowners may attempt a DIY installation, it's essential to note that the Olmo Sierra requires proper setup to ensure optimal performance. Professional installation is recommended, especially for the electrical and refrigerant connections.

Does the mini split come pre-charged with refrigerant?

Yes, the Olmo Sierra is pre-charged with R454B refrigerant for up to 25 ft of line set, allowing for easier installation. Ensure that your installation does not exceed this length to maintain efficiency.

What voltage does the Olmo Sierra mini split require?

The Olmo Sierra ductless mini split operates on a standard voltage of 230V. This makes it compatible with most residential electrical systems.

What warranty does the Olmo Sierra offer?

The Olmo Sierra comes with a solid 5-year parts and compressor warranty, providing peace of mind for your investment. This warranty ensures you are covered for any defects in materials or workmanship.

What SEER rating do I need for energy efficiency?

The Olmo Sierra boasts an impressive SEER rating of 22.0, which indicates high energy efficiency. A SEER rating above 16 is generally recommended for optimal energy savings, making this unit a great choice.