COSTWAY 12000BTU Mini Split Air Conditioner& Heater, 20 SEER2 115V Wall-Mounted Ductless AC Unit Cools Rooms up to 750 Sq. Ft, Energy Efficient Inverter AC with Heat Pump

Where I put it to the test

I installed the Costway 12,000 BTU mini‑split in a well‑insulated, 2‑car garage that doubles as a hobby workspace—about 650–700 square feet with 9‑foot ceilings. It’s a space that sees big swings: hot afternoons with heat soak in summer and shoulder‑season mornings that start chilly. I wanted a single 115V system that could quietly handle both cooling and heating without the cost and complexity of a new 240V circuit. After a full season of cooling and several months of heating, here’s how it fared.

Installation and setup

This is a pre‑charged R32 inverter heat pump, which simplifies installation compared with traditional split systems. But “simplified” isn’t the same as “tool‑free.” You still need to mount the indoor head, set the outdoor unit on a pad or bracket, run the line set and communication cable through the wall, make flare connections, pull a vacuum, and wire a dedicated 115V/20A circuit with a disconnect. That’s standard mini‑split fare.

A few notes from my install:

• Electrical: The 115V requirement is a real advantage if your panel is tight on 240V spaces. I pulled a dedicated 20A circuit, ran 12‑gauge cable to an outdoor non‑fused disconnect, and used liquid‑tight conduit for the final runs. Check local code—some jurisdictions want a service receptacle and may have GFCI requirements for outdoor equipment.
• Penetration and routing: The indoor unit template made marking the wall straightforward. A 2–2.5" hole saw handled the pass‑through. I wrapped the bundle tight to fit cleanly and used a wall sleeve for a neat, sealed penetration.
• Line set and vacuum: The factory flares were clean and the caps came off with good pressure—always reassuring. I torqued to spec, pulled a deep vacuum, and leak‑checked before opening the service valves to release the charge. If any of that sounds foreign, hire a licensed HVAC installer; it’s required to protect the warranty and it’s easy to make an expensive mistake here.
• Condensate: I routed the drain with continuous slope and kept the exterior termination short to reduce freeze risk. If you’re in a cold climate, consider insulating exposed sections or using heat tape.

You’ll likely want a few extras: a line‑hide cover for a tidy exterior run, a wall sleeve, a concrete pad or wall bracket for the outdoor unit, and proper sealants. I also recommend a torque wrench and a quality vacuum pump/gauge set if you’re doing any part of this yourself.

Design and controls

The indoor unit is understated and slim enough to blend into most garages, bonus rooms, and home offices. The louvers motorize both up/down and left/right, which helps push air across a broader area without creating a draft. Build quality feels better than the price suggests; the service ports and electrical terminals are logically laid out and clearly labeled.

Control is via the included remote. It’s basic in the right ways: quick mode changes (auto, cool, dry, heat, fan), four fan speeds plus auto, turbo for rapid conditioning, ECO to throttle consumption, and iFEEL, which uses the remote’s sensor to target the temperature where you’re sitting. The 0.5–24‑hour on/off timer is handy, and the remote’s display goes dark after inactivity, which I appreciated when using it in a guest room for a week. There’s no native Wi‑Fi or app support; if app control is essential, you’ll need a smart IR bridge or a different unit.

Maintenance features are thoughtful. The washable filter pops out easily. The self‑clean cycle bakes the coil at high temperature to reduce mildew buildup; it’s worth running periodically. The outdoor unit has auto‑defrost for winter heating.

Cooling performance

Cooling is where this unit shines. In my 650–700 sq. ft. space, it pulled temperature down decisively and then settled into a quiet, low‑power cruise. The inverter ramp is smooth—no abrupt compressor starts, just a steady hum. Airflow is strong for a 1‑ton head, and the dual‑axis swing does a good job distributing cool air without cold spots near the unit.

With SEER2 20 and EER2 10, I expected efficient operation, and that checks out in daily use. During steady‑state cooling on 85°F days, power draw (via a whole‑home monitor) remained well below 1 kW most of the time. If you’re moving from a portable or window unit, the difference in both comfort and sound is significant.

Heating performance

As a heat pump, it’s very usable in mild to moderately cold conditions. In the 40s and 50s (°F), it heats the space easily and quietly. As temps approach freezing, output drops—as it does with most standard mini‑splits—and the system will periodically defrost the outdoor coil. Those defrost cycles are normal, but you’ll feel brief dips in supply air temperature. In the low 20s (°F) and below, I consider this a “shoulder‑season” heater; it helps a lot, but I keep a small supplemental heater on hand for very cold snaps or quick recovery after the door has been open.

If you plan to rely on heat in a larger or leakier space, consider stepping up a size or improving the envelope. Check the manufacturer’s low‑ambient heating rating for your climate.

Noise

Noise levels are impressively low. On low and medium fan, the indoor unit is quiet enough for a conference call or sleep; it blends into background noise. Even on high during turbo cool, the sound is mostly airflow rather than mechanical. Outside, the unit produces a clean fan whoosh with minimal compressor chatter. Mounting it on a pad with vibration isolators helped keep structure‑borne noise out of the space.

Efficiency and operating costs

The combination of inverter control and a 115V, 20 SEER2 rating makes this an economical daily driver. The system spends most of its time throttled back, sipping power while maintaining setpoint, rather than cycling hard. The ECO mode noticeably trims peaks without making the room feel stagnant. R32 refrigerant is a plus from an environmental standpoint and has good efficiency characteristics; just know that local availability for service top‑offs can vary, so choose an installer who stocks it.

Maintenance and durability

Routine care is straightforward: rinse the filter monthly in heavy use, keep the outdoor coil clear of debris, and run the self‑clean cycle occasionally. In cold climates, ensure the condensate drain is protected from freezing and slopes continuously. So far, fit and finish have held up well—no rattles, no odd vibrations, and tight flare connections after multiple temperature swings. The warranty—five years on parts and eight on the compressor—adds confidence, provided you have a licensed install on record.

What could be better

• No onboard controls: If the remote goes missing or the batteries die, there’s no full control panel on the indoor unit. I’d like a minimal set of onboard buttons for power and mode.
• No native smart control: There’s no built‑in Wi‑Fi or app. That’s not unusual at this price, but worth noting if you’re standardizing on smart thermostats.
• Documentation: The manual is serviceable but generic in places. More unit‑specific install guidance (torque charts, line‑length charge adjustments, drain routing best practices) would help DIY‑inclined users.
• Cold‑weather transparency: The spec sheet doesn’t emphasize low‑ambient heating performance. If you’re in a northern climate, make sure you understand the heat curve and plan supplemental heat accordingly.

Who it’s for

• Garages, bonus rooms, ADUs, and home offices up to roughly 700–750 sq. ft. with decent insulation.
• Homeowners who value quiet operation and want to avoid running a 240V circuit.
• Anyone looking for efficient shoulder‑season heating and strong summer cooling in one unit.

If you need guaranteed heat output well below freezing, look for a cold‑climate model rated for that duty. If you want whole‑home integration with app control and wall stats, you’ll want a more full‑featured system.

Recommendation

I recommend the Costway 12,000 BTU mini‑split for small‑to‑medium spaces where quiet, efficient cooling is the priority and shoulder‑season heating is a welcome bonus. The 115V requirement lowers the electrical barrier, the inverter performance is smooth and frugal, and day‑to‑day comfort is excellent. Installation is approachable with the right tools, though I’d still suggest a licensed HVAC pro to protect the warranty and ensure a proper vacuum, charge, and electrical hookup. It’s not a cold‑climate specialist and it’s light on smart features, but as a competent, budget‑friendly workhorse, it delivers solid value and an easy system to live with.