LG 7,800 BTU Through the Wall Air Conditioner, 115V, AC Wall Unit for Rooms up to 330 Sq. Ft., Perfect for Bedroom or Office, Wall Mounted AC Unit with Remote and 3 Cool & Fan Speeds, White

First impressions and setup

A through-the-wall AC lives or dies by two things: installation and airflow. After a summer with LG’s 7,800‑BTU wall unit in a 300–320 sq. ft. bedroom, I came away impressed by how much cooling it delivers for its size and power draw, with a few quirks that are worth planning for up front.

This is a true through-the-wall unit, not a window AC. I mounted it in an existing wall sleeve, using the included snap-together interior trim and the outdoor mesh grille. The box includes foam and gaskets to seal gaps, and that’s important—positive sealing around the sleeve prevents hot exhaust from recirculating into the intake and keeps noise down indoors.

Two practical notes from installation:
- Weight and handling: it’s heavy enough to be a two-person lift, especially if your sleeve is high on a wall. Plan accordingly.
- Sleeve fit: the chassis measures 24" W x 20.1" D x 14.4" H. If you’re replacing an older, taller sleeve, you may need to shim or build up the interior to eliminate vertical gaps; the trim ring hides small differences, but you still need to block and seal unused space for proper airflow and weatherproofing.

The included instructions are adequate but terse. If your sleeve isn’t an exact dimensional match, the diagrams won’t explain the “why” behind each foam strip. My advice: dry-fit the unit in the sleeve, mark the stop depth, and then place foam so it seals around the sleeve perimeter without obstructing the condenser exhaust or the drain channels. Maintain a slight outward tilt so condensate drains outside.

Cooling performance

At 7,800 BTU, this LG is sized for small-to-medium rooms. In my 300-ish sq. ft. bedroom with afternoon sun, it consistently pulled the temp from 78°F to 72°F in about an hour and held it there without cycling excessively. On the hottest, muggiest nights, I ran it on medium fan in Cool mode and it kept both temperature and humidity in check. The “Turbo” fan option is useful for a quick pull-down when you first turn it on.

Air throw is better than expected for the class. The louver design pushes a tight stream several feet across the room without a dead zone right beneath the unit, and the directional vanes have enough range to avoid blasting a bed or a desk directly.

Thermostat behavior felt sensible: in Cool mode the unit maintained a roughly 2–3°F swing around the setpoint. Energy Saver mode widens that swing a bit but trims runtime substantially (more on that below).

Efficiency and refrigerant

This model uses R‑32 refrigerant and posts a 10.7 EER, which is strong for a through-the-wall AC in this size. In practical terms, it delivered the cooling I needed while keeping input power modest—the sort of unit I’m comfortable running overnight without worrying about a big utility penalty. It runs on 115V and a standard household outlet; I used a dedicated circuit and avoided extension cords, which is the right way to install any fixed AC.

Noise and comfort

No through-the-wall unit is silent, but this LG is well-mannered. On low fan, it’s a steady broadband whoosh that fades into the background while sleeping. Medium is still perfectly livable for a bedroom. High is what I expect from a compact turbo fan: a sharper wind noise that’s fine for quick cooldowns or daytime use.

Two small things to be aware of:
- Compressor start/stop: there’s a soft “thunk” when the compressor engages or disengages. It’s momentary and not jarring, but you’ll notice it in a quiet room.
- Panel rattle: at one point I had a minor rattle from the front grille on high fan. A strip of thin felt tape behind a tab cured it.

Energy Saver mode wakes the fan briefly at intervals to sample room temperature, which can be audible if you’re noise-sensitive. I still used it at night without issue, but if you’re counting sheep, plain Cool + Low fan is the most predictable sound profile.

Controls and remote

The control panel is angled and easy to see when you’re standing over it, which is nice for waist-height installs but less ideal if your sleeve is mounted high. The infrared receiver appears happiest with a downward-angled line of sight; I had to point the remote up and toward the panel to get consistent response when the unit was near the ceiling. The remote itself is simple and covers the basics well: temperature, mode (Cool, Fan, Energy Saver), fan speed, timer, and a high-speed “turbo” fan option.

The display shows set temperature and modes clearly. I’d love a dimmer for overnight use, but the illumination isn’t obnoxious.

Maintenance and build

The washable intake filter slides out easily for quick cleaning. The “clean filter” light is time-based, not a sensor; it will remind you after a fixed number of hours regardless of actual dust load. That’s common in this category, and I prefer a nudge to nothing at all.

Internally, the build feels robust for the price point: solid chassis, sensible drain paths, and outdoor-facing components protected by the included mesh grille. Keep that grille clear of leaves and lint—this unit, like any through-the-wall AC, depends on unobstructed condenser airflow to stay efficient.

A note on airflow and sleeves

Through-the-wall units are uniquely sensitive to how air moves through the sleeve. In one test install using an older, deeper sleeve with a restrictive rear baffle, I triggered a high-temperature protective shutdown during a hot, humid spell. The fix was straightforward: open the knockouts on the sleeve’s rear panel to match the LG’s discharge pattern, remove an unnecessary baffle that was trapping hot air, and ensure there was free space behind the exterior grille.

Once the sleeve was breathing properly, the unit ran without error. The takeaway: don’t just slide a new chassis into an old sleeve and call it done. Verify that the rear grille louvers align with the condenser discharge, that hot air can exit cleanly, and that there’s no obstruction immediately outside. If your legacy sleeve is much taller than the unit, block off the unused interior volume so exhaust can’t recirculate to the intake.

Daily use

• Modes: Cool is the set‑and‑forget choice for stable comfort. Fan‑only works as advertised when you just want air movement. Energy Saver is effective if you’re cost-conscious and can tolerate periodic fan sampling.
• Dehumidification: very good for the size. It took the edge off sticky evenings and helped the room feel cooler at higher setpoints.
• Fit and finish: the included trim kit cleans up the indoor side nicely. Outdoors, the mesh grille is basic but protective.

What I’d change

• Documentation could explain airflow sealing and sleeve adaptation in plain language, not just icons. A one-page “if reusing an old sleeve, do this” would save DIYers time.
• The control panel angle favors low installs. A secondary IR receiver placement or wider acceptance angle would improve remote usability in high mounts.
• A bit more damping on compressor start would reduce the audible thunk in a quiet bedroom.
• A real filter sensor would be nicer than a timer, but that’s rare at this price.

The bottom line

The LG wall AC hits the sweet spot for small-to-medium rooms: strong cooling, sensible power use, and manageable noise. It’s happiest in a properly vented sleeve with a good seal, and if you give it that, it rewards you with reliable performance and lower energy bills. The remote and controls are straightforward, the filter is easy to service, and the R‑32 refrigerant plus 10.7 EER are welcome modern touches.

Recommendation: I recommend this unit for bedrooms, home offices, and similar spaces up to about 330 sq. ft., provided you pay attention to sleeve compatibility and airflow. If you’re dropping it into a very old, oversized, or restrictive sleeve and aren’t comfortable making minor adjustments (or replacing the sleeve), you may want a model bundled with a new, matched sleeve to simplify the install. For everyone else, this LG offers efficient, confident cooling with few compromises.