LG LT12124CNR Review: 11,800 BTU Wall AC on 115V
LG's largest 115V cooling-only wall unit, rated 11,800 BTU for rooms up to 530 sq ft, with an EER of 10.6, a 1110 watt draw and the universal LG chassis.
By Daniel Brooks
Updated October 19, 2026
The LG LT12124CNR answers a question many apartment dwellers ask: how much cooling can you get through a wall sleeve without running a new high-voltage circuit? LG’s answer is 11,800 BTU, enough for rooms up to 530 square feet, on a standard 115 volt outlet. It is a cooling-only unit that uses the same 24 inch universal chassis as LG’s smaller wall models, which makes it one of the most practical upgrades in our cooling-only through-the-wall air conditioners category.
It has 78 ratings on Amazon so far, and it is the newest of LG’s current wall units in our database.
Our Verdict
If your existing wall unit struggles to keep a living room or large bedroom cool, the LT12124CNR is the easiest way to get more capacity without an electrician. It cools up to 530 square feet, lists an EER of 10.6, draws 1110 watts and uses R-32 refrigerant. You get LG’s usual feature set: three cooling and fan speeds, energy saver mode, dry mode, 4-way air deflection, a 24 hour timer, a filter alert and a remote.
The trade-offs are the ones you expect from a conventional wall unit. LG lists 60 dB, there is no Wi-Fi or heat, and the sleeve is sold separately. It is also a heavy unit at 76 pounds.
LG 11,800 BTU Through the Wall Air Conditioner
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Key Specifications
| Feature | Specification |
|---|---|
| Brand | LG |
| Model | LT12124CNR |
| Type | Cooling-only through-the-wall air conditioner |
| Cooling Capacity | 11,800 BTU |
| Room Size | Up to 530 sq ft |
| Power | 115 volts, 1110 watts |
| Efficiency | EER 10.6 |
| Refrigerant | R-32 |
| Noise Level | 60 dB (listed) |
| Dimensions | 24 x 14.4 x 20.1 inches (W x H x D) |
| Wall Cutout | 25.88 W x 15.53 H inches |
| Weight | 76 pounds |
| Wall Sleeve | Sold separately |
| Warranty | 1 year limited |
Cooling Capacity and Room Size
LG rates the LT12124CNR for rooms up to 530 square feet. In the ENERGY STAR chart below, that falls inside the 12,000 BTU band, so the rating lines up with its 11,800 BTU output. It suits a medium living room, a large primary bedroom, a studio apartment or a home office that gets afternoon sun.
The step up from a 10,000 BTU class wall unit to this model adds a meaningful amount of capacity. That is often the difference between a room that holds its set point at 4 p.m. and one that drifts warmer all afternoon, especially on upper floors.
ENERGY STAR publishes this general guide for sizing a room air conditioner by floor area:
| Room Size (sq ft) | Cooling Capacity (BTU/hr) |
|---|---|
| 100 to 150 | 5,000 |
| 150 to 250 | 6,000 |
| 250 to 300 | 7,000 |
| 300 to 350 | 8,000 |
| 350 to 400 | 9,000 |
| 400 to 450 | 10,000 |
| 450 to 550 | 12,000 |
| 550 to 700 | 14,000 |
| 700 to 1,000 | 18,000 |
Adjust for your room: reduce capacity by 10 percent for a heavily shaded room, increase it by 10 percent for a very sunny room, add 600 BTU for each regular occupant beyond two, and add 4,000 BTU if the unit cools a kitchen. Source: ENERGY STAR.
The 115 Volt Advantage
Many wall units at this capacity need a dedicated high-voltage outlet, which many apartments do not have in the right spot. The LT12124CNR runs on a standard 115 volt outlet, and at 1110 watts it fits on a typical household circuit. Ideally, give it a circuit of its own, or at least avoid sharing it with a microwave, space heater or other high-draw appliance.
That makes it a direct upgrade path for renters who already have an LG-style sleeve and a normal outlet next to it.
Installation and Sleeve Fit
This is a through-the-wall chassis that LG says is not properly vented for a standard window installation. The unit measures 24 inches wide, 20.1 inches deep and 14.4 inches tall, and LG describes it as a universal design that fits most sleeves. For a new installation, LG lists a wall cutout of 25.88 inches wide by 15.53 inches high for the sleeve.
The sleeve is sold separately. In the box you get a trim kit for the indoor side, a plastic mesh grille for the outdoor side, insulation foam, a washable filter and the remote. At 76 pounds, lift it into the sleeve with a helper.
Energy Use and Efficiency
A listed EER of 10.6 is solid for a conventional wall unit of this size, and it keeps running costs close to LG’s smaller models per BTU delivered. Energy saver mode keeps the fan running but shuts off the compressor once the room reaches your set temperature, and the 24 hour timer lets you cool the room only when you need it.
Noise
At 60 dB listed, the LT12124CNR is louder than LG’s smaller wall units. That is the cost of a larger compressor and fan in the same chassis size. It is fine for a living room or office, and workable in a bedroom on low fan speed, but light sleepers may prefer a smaller unit in a small bedroom or an inverter system.
Controls and Everyday Use
Controls are LG’s familiar layout: a digital front panel and a remote, three modes, three speeds and the timer. Dry mode removes moisture on humid days, and 4-way air deflection lets you aim air where people sit. The check filter alert reminds you to rinse the washable filter. There is no app or voice control.
Before You Buy
Measure first. Check the inside width and height of your current sleeve, the wall depth and the outlet position. If the outlet sits on the wrong side of the opening, plan the cord route before installation day rather than relying on an extension cord.
Think about where the air will go, too. A wall unit set high on the wall throws air across the room well, but a unit set low near furniture can short-cycle if a sofa blocks its airflow. Leave clear space in front of the grille.
Who It Suits Best
The LT12124CNR suits renters and owners with an existing sleeve who need more cooling than a 10,000 BTU class unit and only have a 115 volt outlet. It is a natural fit for living rooms, large bedrooms and studios up to 530 square feet. It is less suited to small bedrooms, anyone who wants smart control, or rooms that also need winter heat.
Pros and Cons
| Pros | Cons |
|---|---|
| 11,800 BTU for up to 530 sq ft | Wall sleeve sold separately |
| Runs on a standard 115V outlet | 60 dB listed sound level |
| EER 10.6 with R-32 refrigerant | No Wi-Fi or app |
| Universal chassis fits most sleeves | Heavy at 76 pounds |
| Energy saver, dry mode and timer | No heat mode |
Who Should Buy It
| Who Should Buy It? | Who Should Look Elsewhere? |
|---|---|
| Living rooms up to 530 sq ft | Small bedrooms |
| Homes with only 115V outlets | Smart home users |
| Upgrades from a smaller LG wall unit | Rooms that need winter heat |
| Sunny or upper floor rooms | Very light sleepers |
For more options, see our picks for the best 115V through-the-wall air conditioners and the best 12,000 BTU through-the-wall air conditioners.
Final Verdict
The LG LT12124CNR is the most cooling you can get from LG through a wall sleeve on a normal outlet. For living rooms and large bedrooms up to 530 square feet, it is an efficient, straightforward upgrade. Just expect a bit more noise than a smaller unit. You can check the current price and details for the LG 11,800 BTU Through the Wall Air Conditioner.
Frequently Asked Questions
Does the LG LT12124CNR need a special outlet?
No. It runs on a standard 115 volt outlet and draws 1110 watts.
What size room does it cool?
LG rates it for rooms up to 530 square feet.
What wall cutout does it need?
LG lists a wall cutout of 25.88 inches wide by 15.53 inches high. The sleeve is sold separately.
Is it an inverter unit?
No. It uses a conventional rotary compressor and lists an EER of 10.6.
About the author
Daniel Brooks is a home cooling editor at WikiCooling, covering window, portable, through-the-wall and mini-split air conditioners, fans, and dehumidifiers. He researches cooling capacity, energy efficiency, noise levels, installation requirements, and buyer feedback to help homeowners choose the right unit for their room size, climate, and budget.