COSTWAY 12000BTU Mini Split Review: quiet 115V unit that actually heats and cools decently on a budget

I picked up the COSTWAY 12000BTU Blast Series mini split for a roughly 600–650 sq ft area that needed both cooling in summer and some backup heat in winter. I went for this one mainly because it runs on 115V, so I didn’t have to mess with a 240V circuit, and because the price was clearly lower than the big brands. I wasn’t expecting anything fancy, just something that would keep the space usable without sounding like a jet engine.

After the first week, my main takeaway was pretty simple: it works and it’s quieter than I thought. The indoor unit doesn’t scream, and the outdoor unit hums along in the background. It’s not luxury-level silent, but you can easily talk or watch TV with it running. I care more about function than looks, and on that front it’s doing its job: it cools fast, and the heat side is better than a basic space heater, especially for maintaining a steady temperature.

That said, this is not a plug-and-play toy. Even though a lot of people DIY it (me included), you still need to be comfortable with running a dedicated circuit, drilling a big hole through a wall, and pulling a vacuum on the lines. The manual is pretty generic and you’ll probably end up on YouTube like I did. If you’re not handy, factor in the cost of a real HVAC installer, because that’s where the total price can creep up.

Overall, after living with it, I’d describe this thing as good value for money with a few quirks. Performance and noise are solid for the price, but the documentation, Wi‑Fi setup, and some of the provided install accessories are a bit half‑baked. If you go in knowing that, it’s easier to be happy with it.

For me, the main selling point is value. You’re getting a 12000BTU, 115V, 20 SEER2 mini split that can both cool and heat for a price that’s clearly lower than the big Japanese or high-end brands. If you’re willing to either DIY the install (with some tools) or pay a reasonable amount to an installer, the total cost still ends up pretty attractive compared to a name-brand system.

There are some hidden costs, though. I had to buy or already own things like:

• Vacuum pump and manifold gauges (around $100–$120 if you don’t have them)
• Outdoor wall bracket or stand (around $30–$50)
• Line set cover for a cleaner exterior look (around $30–$40)
• Extra insulation tape and misc hardware

So in practice, the value is best for people who are at least somewhat handy and willing to watch a few install videos, read forums, and take their time. If that’s you, you end up with a quiet, efficient system for much less than a big-brand setup. If you’re planning to fully outsource everything, the price gap shrinks and you might start looking at other brands too.

Overall, I’d say the price-to-performance ratio is pretty solid. Cooling and heating performance are good, noise levels are low, and the warranty is decent. You do give up some polish: the manual is generic, Wi‑Fi is clunky or basically useless for some people, and the included install materials are just okay. If you’re fine with those trade-offs, it’s good value. If you want something fully polished and idiot-proof, you’ll probably need to spend more.

Design-wise, the indoor unit is pretty standard mini split white box. It’s about 31" wide, 8" deep, and 11.5" tall. Nothing fancy, nothing ugly. It blends in on a white wall and doesn’t scream for attention. The front panel lifts for filter access, and the louvers move both up/down and left/right automatically, which actually helps move air around the room better than some cheaper units that just flap up and down.

The outdoor unit is compact for a 12k BTU system and sits fine on a wall bracket or ground stand. I appreciated that the service valves and connections are accessible, but you do need to be careful when bending the larger copper line; it kinks pretty easily if you’re rough or impatient. The manufacturer clearly expects a neat install with the lines coiled or routed properly. If you just jam it into place, it’s going to look sloppy and you risk damaging the tubing.

One design choice I’m not a fan of: no backup controls on the indoor unit. Everything is done through the remote. It works, but it’s a single point of failure. If the remote dies, you can’t just walk up to the unit and turn it on or change the temp. At this price, I get it, but even a basic on/off + temp rocker switch would have been nice as a safety net.

Overall, the design feels functional and honest. It’s not trying to be a decor piece; it’s a white plastic box that blows hot or cold air. The airflow pattern is good thanks to the 4‑way swing, and the size is reasonable for the capacity. If you care a lot about aesthetics, you’ll probably call it “meh but fine.” If you care more about performance and footprint, the design is totally acceptable.

In day-to-day use, the comfort level is pretty good. The indoor fan has multiple speeds plus an auto setting, and the 4‑way swing actually matters. Instead of one cold blast in your face, you can let it slowly sweep the room. In my setup, that means the whole space gets a more even temperature instead of hot/cold zones. The iFEEL function on the remote is also useful: it uses the temperature at the remote instead of just at the unit, so if you’re sitting farther away, the system doesn’t shut off too early.

Noise-wise, the indoor unit on low and sleep mode is quiet enough to sleep with. It’s not dead silent, but it’s more like a soft fan noise than a loud whoosh. On high or turbo, you definitely hear it, but it’s still reasonable. You can watch TV or have a conversation without raising your voice. The outdoor unit is also on the quiet side; if you’re indoors with windows closed, you barely notice it. Outside, standing near it, it’s just a steady hum, not a rattling mess.

The sleep mode and 0.5–24 hour timer are handy if you don’t want it blasting all night. The remote display turning off after about 10 seconds of no input sounds like a tiny detail, but at night it’s actually nice not to have an extra glowing screen. The only thing I’d nitpick is that sometimes the temperature swing (the difference between when it turns on and off) feels a bit wide in auto mode. If you’re picky, you’ll probably just set it manually instead of trusting full auto.

Overall comfort score for me is high for this price range. The combination of low noise, decent airflow control, and usable sleep features makes it easy to run this thing all day and night without getting annoyed. It’s not luxury-level climate control, but for a budget mini split, it’s more than good enough.

On build quality, the COSTWAY mini split landed somewhere between “cheap Amazon special” and “big brand”. The indoor unit plastic doesn’t feel premium, but it also doesn’t feel flimsy. The cover opens and closes cleanly, the louvers move smoothly, and there were no weird rattles or creaks once mounted correctly. The filters slide out easily for cleaning, which matters long term because if it’s annoying, you just don’t do it.

The outdoor unit feels sturdier. The metal housing is decent, and the fact that both the indoor and outdoor sections held pressure from the factory (as mentioned in one of the reviews and matched my experience) is a good sign. When I cracked the caps before connecting the lines, there was a solid hiss, which basically means it left the factory sealed properly. The unit also has auto defrost for the outdoor coil, which should help in winter and keep ice from building up and killing efficiency or damaging the unit.

One thing to note is that the line set insulation and some of the included putty/tape are on the cheap side. They work, but if you want a really clean and better-protected install, you’ll probably add better insulation wrap and a proper line cover. That’s less about durability of the internal components and more about protecting the lines from sun and weather so the system lasts longer.

COSTWAY backs it with 5 years on parts and 8 years on the compressor, which is actually pretty solid on paper, especially for the price. That doesn’t magically make it bulletproof, but it does show they’re at least confident enough to put it in writing. Based on the construction and how it runs so far, I’d say it feels like it should last if installed correctly and maintained (clean filters, keep the outdoor coil clear). It’s not a top-tier pro unit, but it doesn’t feel like disposable junk either.

On the performance side, this is where the COSTWAY 12k BTU unit actually surprised me in a good way. In cooling mode, it drops the temperature fast in my roughly 600–650 sq ft area. Starting from around 80–82°F, I can feel a real difference within 10–15 minutes, and after 30–40 minutes the whole space is comfortable. The air coming out of the indoor unit is properly cold, not just “cool-ish,” and the fan can push a decent volume of air across the room, especially on high or turbo mode.

The heating performance is better than I expected from a budget mini split. It’s not going to replace a full house furnace in a freezing climate, but for a garage, shop, or a main room, it does a good job. It’s more efficient and more comfortable than a portable space heater because it spreads the heat evenly and doesn’t just cook one corner. In mild winter weather, it’s enough on its own. In deeper cold, you might still want a little backup heat, but as a primary or secondary source, it holds its own.

Energy-wise, the inverter compressor helps a lot. Once the room gets close to the set temperature, you can hear the unit ramp down instead of cycling on/off constantly. That’s better for both comfort and your power bill. It’s rated at 20 SEER2 and about 1650 kWh/year, which lines up with what I’m seeing – it’s not sipping power like a top-tier premium unit, but for a 115V system, it’s pretty efficient. You don’t feel guilty running it all day in peak season.

Overall, I’d rate performance as strong for the money. Cooling is where it shines the most, heating is solid and usable, and the inverter behavior keeps things steady. If you’re trying to handle a full 750 sq ft with poor insulation and crazy outdoor temps, you’re pushing it, but for a mid-sized, decently insulated area, it does the job without drama.

Out of the box, the COSTWAY 12000BTU mini split is a fairly complete kit for a budget system. You get the indoor head, outdoor condenser, about 13 ft of pre-flared copper lines (liquid and gas), communication cable, an 8 ft power line, a short drain hose, some putty, a wall sleeve, a basic remote, and mounting hardware for the indoor unit. There’s no wall bracket for the outdoor unit, so if you want it off the ground like I did, you’ll need to buy a separate stand or wall mount.

The system comes pre-charged with R32 refrigerant in the outdoor unit, which is nice because you don’t have to mess with adding refrigerant for a standard-length line set. It’s rated for 20 SEER2, which on paper is pretty efficient for a 115V, 1‑ton unit. They advertise coverage up to 750 sq ft, which I’d say is realistic for a reasonably insulated space. In a badly insulated area, it’ll still work, but don’t expect miracles at the far corners.

The remote is simple but covers a lot: you can control mode (cool, heat, dry, fan, auto), fan speed, swing, sleep, turbo, and there’s an iFEEL function where the unit follows the temperature at the remote. The display on the remote shuts off automatically after about 10 seconds, which sounds minor but is actually nice at night because you’re not staring at a glowing screen. There’s no control panel on the indoor unit itself though, so if you lose or break the remote, you’re basically stuck until you get another one.

Overall, in terms of what’s included, I’d say it’s mostly complete but a bit bare‑bones. The basics are there to get it running, but you’ll probably end up buying a few extras: more insulation tape, maybe a better wall sleeve, a line set cover for looks, and some kind of support for the outdoor unit. For the price point, that’s acceptable to me, but don’t assume the box has literally everything you need from start to finish.