OLMO Sierra 36,000 BTU 3-Zone 12k+12k+18k Wall Mount, 230V, R410A - Ductless Mini Split Air Conditioner Heat Pump | No Kit No Kit No Kit

SEER221 Heatsdown to−13°F Coolsup to115°F

White Installation Kit OLMO 36000 BTU Ductless Mini Split Air Conditioner with R410A refrigerant 230V SEER 21.0 Inverter

SEER221 Heatsdown to−13°F Coolsup to115°F

OLMO 36000 BTU Ductless Indoor Unit Mini Split Air Conditioner with R410A refrigerant 230V SEER 21.0 Inverter

SEER221 Heatsdown to−13°F Coolsup to115°F

OLMO 36000 BTU Ductless Outdoor Unit Mini Split Air Conditioner with R410A refrigerant 230V SEER 21.0 Inverter

SEER221 Heatsdown to−13°F Coolsup to115°F

Remote Control OLMO 36000 BTU Ductless Mini Split Installation Kit with R410A refrigerant 230V SEER 21.0 Inverter

SEER221 Heatsdown to−13°F Coolsup to115°F

Components OLMO 36000 BTU Ductless Mini Split Smart WiFi Control with R410A refrigerant 230V SEER 21.0 Inverter

OLMO5-Yr Warranty55 shoppers interested

OS-MSR36-230VO12WM12WM18WM-NO/NO/NO

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Product specifications

Brand	Olmo
Voltage	230V
SEER	21
WiFi	Included
Zone	Three Zone
Type	Wall Mount
Freon	R410A
Compressor	Inverter

See full Tech Specs

Questions about this system?

Answers in seconds — tap a question below

Up to about 1,650 sq ft across 3 rooms at average conditions: each indoor unit is sized for its own room — 12,000 BTU up to about 550 sq ft, 18,000 BTU up to about 800 sq ft. The 36,000 BTU outdoor unit is the limit for all rooms together. For a room-by-room load calculation, ask your installer for an ACCA Manual J. Not sure? Call (855) 775-4822 and we'll confirm the right size 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 36,000 BTU (3-ton). BTU tells you the capacity; SEER2 tells you the efficiency.
It uses R410A — a proven, widely serviced refrigerant. 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 21.0 — 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 21.0) 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. Each indoor unit has its own remote/thermostat — set different temperatures or turn one off, so you only condition the rooms you use and save energy on the ones you're not. One outdoor unit powers them all, keeping install and running costs lower than separate systems per room.
Yes — WiFi is 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-MSR36-230VO, OS-M12SRW-230VI, OS-M12SRW-230VI, OS-M18SRW-230VI. 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 items over $300 within the U.S., and our team can help with sizing and support.

Hurry to buy! Get your mini-split system with R-410A refrigerant (limited stock)

Important info

R-410A is being phased down in favor of newer refrigerants; inventory is limited.
Existing R-410A systems remain serviceable; parts and qualified service are widely available.
Check local codes and rebates. Some incentives prioritize high-efficiency heat pumps (R-32/R-454B).
We stock both R-410A and next-gen options—choose what fits your timeline and budget.

Browse: R-410A systems · R-32 · R-454B

Free Shipping on items 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

Complete 3-Zone System

Heat or cool 3 rooms independently from one 36000 BTU outdoor unit (12K+12K+18K) — every zone sets its own temperature, delivered by wall mount indoor units.

Inverter Efficiency — SEER2 21

A variable-speed inverter compressor ramps to match the load instead of cycling on/off, holding SEER2 21 on 230V — steady comfort with noticeably lower energy bills.

Right-Sized Coverage

Heats & cools up to about 1,650 sq ft across 3 rooms at average conditions (about 22 BTU per sq ft).

Sierra Wall Mount

OLMO's Multi-Zone Sierra Series is a versatile HVAC solution designed to provide efficient heating and cooling for multiple rooms, equipped with advanced inverter technology for precise temperature control and significant energy savings. Using eco-friendly R410A refrigerant, the system ensures reliable performance with minimal environmental impact. Perfect for residential or commercial applications, the Sierra Series offers quiet operation, flexible installation, and user-friendly controls, making it an ideal 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 R410A 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.

All Accessories Included

With your purchase, you receive a comprehensive MiniSplit system. MiniSplits4Less ensures you have everything needed for a seamless installation. Your package includes an Indoor Unit, Outdoor Unit, Remote Control, Manuals, optional LineSet, and a Smartkit (WIFI). We've meticulously thought of every detail to provide you with all the essentials for your installation.

OLMO Sierra 3-zone system package contents

Technical Specifications

Indoor Unit Specs OS-M12SRW-230VI

Indoor Unit Specs — OS-M12SRW-230VI
Model	OS-M12SRW-230VI
Unit Dimensions (WxDxH)	37.38x10.75x8.13 in
Net/Gross Weight	19.84/24.25 lb
Packing Dimensions (WxDxH)	39.38x13.19x6.38 in
Power Supply	208-230V, 1Ph, 60Hz
Noise Level (Hi/Med/Lo)	39/35/30 dB

Indoor Unit Specs OS-M18SRW-230VI

Indoor Unit Specs — OS-M18SRW-230VI
Model	OS-M18SRW-230VI
Unit Dimensions (WxDxH)	48x12.63x9.25 in
Net/Gross Weight	31.97/37.48 lb
Packing Dimensions (WxDxH)	51.75x15.44x12.50 in
Power Supply	208-230V, 1Ph, 60Hz
Noise Level (Hi/Med/Lo)	45/41/37 dB

Outdoor Unit Specs OS-MSR36-230VO

Outdoor Unit Specs — OS-MSR36-230VO
Model	OS-MSR36-230VO
Net/Gross Weight	188.5/220.5 lb
Power Supply	208-230V, 1Ph, 60Hz
Maximum Fuse Size	50 A
Min. Circuit Ampacity	32.2 A
Copper Line Size (Liquid/Gas)	1/4"/3/8"
Noise Level	59 dB
Airflow	3.411 CFM

System Specs

System Specs
Cooling Capacity	36,000 BTU
SEER2	21
Zones	3
Voltage	230V
Refrigerant Type	R410A
Compressor	Inverter
WiFi	Included
Heating Capacity	36,000 BTU/h
Cooling Capacity Range	32,000 BTU/h
Operating Range (Cooling)	14~114.8 °F
Operating Range (Heating)	-13~75.2 °F
Refrigerant Precharge	25 ft
Max Height Difference	15 ft
COP	3.37

Series Comparison Table

Technical specifications for every model in the Sierra series — this product is one of them.

Indoor Models	OS-M09SRW-230VI	OS-M12SRW-230VI	OS-M18SRW-230VI	OS-M24SRW-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-MSR18-230VO	OS-MSR24-230VO	OS-MSR36-230VO	OS-MSR42-230VO
Power Supply V-Ph-Hz	208/230V-1Ph-60	208/230V-1Ph-60	208/230V-1Ph-60	208/230V-1Ph-60
Capacity Btu/h	18000	24000	32000	42000
Cooling
EER2 Btu/h	12.5	12.5	12.5	10.5
SEER2 Btu/h	21.0	22.0	21.0	20.0
Heating
Rated Capacity Btu/h	18000	24000	36000	42000
HSPF2 Btu/h	9.50	9.05	9.00	8.95
COP2 W/W	3.45	3.66	3.37	3.17
Minimum Circuit Ampacity A	23	25	32.2	35
Max Fuse A	30	30	50	50
Outdoor Air Flow (Hi) CFM	1850	2350	3411	3411
Outdoor Side Noise Level dB(A)	55	55	59	63
Dimensions (WxHxD) in	33.88×26.38×12.25	37.38×33×13.38	37.38×41.38×13.38	37.38×41.38×13.38
Outdoor Unit Packing (WxHxD) in	39×17.75×28.75	43.75×18.13×36.25	43.75×18.13×47.25	43.75×18.13×47.25
Net/Gross Weight lbs	116.8/125.6	158.7/169.5	188.5/220.5	198.4/224.5
Refrigerant
Refrigerant Type/Quantity oz	R410A/63.49	R410A/81.13	R410A/105.82	R410A/120
Refrigerant Precharge ft	50	75	98	98
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	66/197	66/246	66/262
Ambient Temperature
Outdoor (Cooling) °F	14~114.8	14~114.8	14~114.8	14~114.8
Outdoor (Heating) °F	-13~75.2	-13~75.2	-13~75.2	-4~75.2

What’s Included

What’s Included
Outdoor condenser	OS-MSR36-230VO
Indoor unit	OS-M12SRW-230VI
Indoor unit	OS-M12SRW-230VI
Indoor unit	OS-M18SRW-230VI

Installation kit is not included in the selected option — pick 16ft, 25ft or 50ft above to add one.

Shipping & Returns

Free shipping on every item over $300.
Delivery estimate for your ZIP is shown in the buy box above.
Returns accepted per our policy — unopened units in original packaging.

Shipping & delivery policy Returns policy

Warranty

5-year manufacturer warranty

Limited manufacturer warranty on the compressor and sealed system components.
Your order number is the proof of purchase — keep it for any claim.

Full warranty terms

Multiple Control Methods

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

Frequently Asked Questions

How many rooms can the Olmo 3 Zone 36,000 BTU mini split cool?

The Olmo 3 Zone 36,000 BTU mini split can effectively cool up to three rooms, with a total coverage area of up to 1,500 square feet. This makes it ideal for multi-zone applications where individual comfort control is desired.

Can I mix BTU sizes in my Olmo mini split system?

Yes, you can mix BTU sizes in your Olmo mini split system, such as pairing a 12k BTU unit with a larger 18k BTU unit. However, ensure that the total BTU does not exceed the system's capacity of 36,000 BTU for optimal performance.

Do all zones in the Olmo mini split run simultaneously?

No, in the Olmo 3 Zone mini split system, each zone can be controlled independently, allowing you to heat or cool specific areas as needed. This flexibility can enhance energy efficiency compared to running multiple single-zone units.

What is the warranty on the Olmo mini split system?

The Olmo mini split system comes with a 5-year parts and compressor warranty, providing peace of mind for your investment. This warranty ensures that you are covered for any manufacturing defects or issues during the specified period.

Does the Olmo mini split come pre-charged with refrigerant?

Yes, the Olmo mini split system is pre-charged with R410A refrigerant for up to 25 ft of line set, facilitating easier installation. This means you won't need to add refrigerant if your installation falls within this range.

What SEER rating does the Olmo mini split have and is it efficient enough?

The Olmo 3 Zone mini split boasts an impressive SEER rating of 21.0, making it highly efficient for both cooling and heating. This efficiency rating helps reduce energy costs and meets or exceeds current energy standards.

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OLMO Sierra 36,000 BTU 3-Zone 12k+12k+18k Wall Mount, 230V, R410A - Ductless Mini Split Air Conditioner Heat Pump | No Kit No Kit No Kit

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