Best Through-the-Wall Air Conditioners (2026)

LG's wall unit lists 9,800 BTU of cooling, an EER of 10.7 and R-32 refrigerant, with coverage up to 440 square feet on a 115V supply. EER is cooling output divided by power at fixed conditions, so a 10.7 is a respectable figure for a wall unit of this size.

The listing is clear that it is suited to a through-the-wall installation and is not made for a window, which matters because a sleeve unit has a different chassis. Against the 11,800 BTU LG it covers 90 fewer square feet but is easier on the electrical supply, and against the OLMO units it has a stated EER and a larger service network.

Ownership is the wall-unit routine: a washable filter, a coil clean in spring and checking the sleeve seal each year. The sleeve is a separate purchase, so confirm the size before ordering. If you are replacing an older unit, take the old chassis dimensions and the sleeve depth to the store or compare them against the listing, because a few inches of difference decides whether it fits.

The larger LG lists 11,800 BTU, EER 10.6 and coverage up to 530 square feet on a 115V supply with R-32 refrigerant. It is built for through-the-wall installation and is not recommended for a window.

The difference from the 10,000 BTU model is capacity and a one-tenth EER drop, which is normal as the compressor grows. It suits a large bedroom or a small open living area. Against the OLMO 12,000 BTU it has a stated EER and a stronger brand, but the OLMO adds a smart kit.

As with all of these, the sleeve is a separate item, the opening must match the chassis and a dedicated 115V circuit is wise because current at this size is high. Clean the filter every few weeks and the coil each spring. Because it is heavy, plan for two people and a temporary support so the unit does not drop onto the sleeve edge during installation.

OLMO's 12,000 BTU wall unit is cooling only, runs on 115V single phase at 60Hz, uses R-32 refrigerant and has a built-in smart kit for app control. The listing asks you to verify that you have the right receptacle, which is a real warning at this size.

It does not state an EER in the data, so efficiency is a gap compared with the LG units. It does offer the highest cooling capacity here on a standard supply, and the smart kit adds scheduling. The wall sleeve is not part of the listing, so budget for one.

Ownership is the usual wall-unit routine. Check the receptacle before you buy, keep the filter clean and inspect the sleeve seal each year, because a leaky sleeve wastes much of the cooling. The built-in smart kit is convenient for scheduling, but keep the manual controls reachable so you can run the unit if the app is unavailable.

This OLMO combines 8,000 BTU of cooling with a heating function, a built-in smart kit and a remote, on a 115V single-phase supply. The listing title names a wall sleeve, which makes it one of the few options here that can be installed without a separate sleeve purchase.

Including the sleeve removes a common point of confusion, since sleeve size has to match the chassis. The data does not give a heating capacity or an EER, so treat the heat as supplemental. Against the TCL and Keystone it offers the sleeve bundle, and against the LG it has less capacity.

Ownership is routine. Seal the sleeve to the wall, keep the filter clean and check the supply receptacle, since the listing explicitly warns to verify it. Because the bundle includes a sleeve, check that its depth matches the thickness of your wall before you start cutting.

TCL pairs 8,000 BTU of cooling with a 4,200 BTU heater, a built-in dehumidifier mode and Wi-Fi control on a 115V supply. The stated 4,200 BTU of heat is the useful number: it is about 1,230 watts of resistance heat, a little under a standard space heater, so it takes the chill off a room, not warms a cold one.

Its role is the smart, mid-capacity wall unit. Compared with the Keystone, which lists the same 4,200 BTU of heat, it adds Wi-Fi and voice, and compared with the OLMO heat unit it states its heating capacity.

Ownership is routine. The sleeve is separate, so check the opening size before you order, and keep the filter and coil clean. Use the dehumidifier mode in shoulder seasons when the air is damp but the temperature is mild, which saves running the full cooling cycle.

Keystone's wall unit lists 8,000 BTU of cooling and 4,200 BTU of supplemental heat, with dehumidification and fan modes on a 115V supply. It is the plain version of the combo wall unit, without the app features of the TCL.

That simplicity is the value. It cools and heats an average bedroom, uses a standard circuit and has fewer electronics to fail. Compared with the TCL it gives up Wi-Fi, and compared with the LG it has less capacity and no stated EER.

Ownership is the wall-unit routine: a sleeve is required, the filter needs regular washing and the sleeve seal needs a yearly check. Confirm the sleeve opening before you order. Because it has few electronics, it is a reasonable choice for a rental or a seldom-used guest room where simplicity beats features.