What size room does the LG 11,800 BTU 230V Through-the-Wall Air Conditioner cool?

It is rated to cool a room up to 550 sq ft (11,800 BTU · 3.5 kW).

Do I need a professional to install the LG 11,800 BTU 230V Through-the-Wall Air Conditioner?

Not to replace a unit, but usually yes for a new opening. Sliding it into an existing wall sleeve it fits is a job you can do yourself (it is heavy, so plan on two people), with no refrigerant work. A new installation means cutting an opening through an exterior wall and fitting a sleeve, which is contractor work and usually needs a building permit. It runs on 230 volts, so it needs a matching 230-volt outlet on its own circuit, and adding one is a job for an electrician.

Through-the-wall unit

LG · Model LT1236CER

11,800 BTU 230V Through-the-Wall Air Conditioner

Name: LG 11,800 BTU 230V Through-the-Wall Air Conditioner
Brand: LG

A through-the-wall air conditioner rated at 11,800 BTU for rooms up to 550 sq ft. It installs in a wall sleeve.

$579

Live price at Sylvane

Price checked Oct 27, 2026

Buy at Sylvane In stock

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Will it cool your room?

Room size (assumed)450 sq ft ≈ 41.8 m²

Fits a 450 sq ft room

This unit's cooling matches a 450 sq ft room. Set your room size to check the fit for your space.

Compare wall units by the sleeve they fit

At a glance

Best for replacing a through-the-wall unit in an existing wall sleeve.

Cooling

11,800 BTU

Size

Noise

Install: Slides into a wall sleevePermission: A new wall opening usually needs a permit

Where to buy

2 retailers

SylvaneLowest In stock$579Buy
Electronic Express In stock$699Buy
AmazonPrice and stock shown on AmazonSearch Amazon

Prices & stock checked Oct 27, 2026.compare.ac may earn a commission on purchases, at no cost to you. It never changes the price you pay.As an Amazon Associate I earn from qualifying purchases.

Performance

Cooling capacity: 11,800 BTU · 3.5 kW
Heating capacity: Cooling only
Room coverage: up to 550 sq ft
Energy Star: Not published
CEER: Not published
Annual energy (cooling): Not published

Noise, size & features

Model number: LT1236CER
Indoor noise: Not published
Outdoor noise: Not published
Indoor unit: Not published
Outdoor unit: None
Refrigerant: Not published
Wi-Fi / app: Not published
Outdoor unit needed: No
Wall sleeve: Fits 26 in. standard sleeves (25½ to 27 in.)

Will it fit your wall sleeve?

LG's manual lists the existing sleeves it fits (25½ to 27 inches wide, from Frigidaire, GE/Hotpoint, Whirlpool, Fedders/Emerson, Carrier and Friedrich), but LG strongly recommends a new LG sleeve and says an existing sleeve's rear louvers must be redirected. LG's own sleeve is the AXSVA1, or the AXSVA4 with a stamped grille (about 25⅞ x 15½ x 16¾ in.). Source: LG owner's manual (hosted by P.C. Richard)

Every through-the-wall AC and PTAC by the sleeve it fits

Installation & the rules that apply

This is a through-the-wall air conditioner. It sits in a sleeve built into an exterior wall, so the window-unit mounting and bracket rules do not apply to it. Swapping it into an existing sleeve is a like-for-like replacement; cutting a new opening changes the building's exterior wall, which usually needs a building permit and, in a condo, co-op or historic building, approval first.

Installation

Slides into a wall sleeve

Refrigerant

GeneralRenters: get written landlord consent firstReviewed June 2026Often blocks install

GeneralCondo / HOA: exterior changes need approvalReviewed June 2026Permit required

GeneralHistoric / listed buildings: consent before any exterior unitReviewed June 2026Permit required

MassachusettsMassachusetts: local historic district approval (MGL c.40C)Reviewed June 2026Permit required

United StatesUS: local mechanical and electrical permits (vary by city)Reviewed June 2026Permit required

See full rules by region

Common questions about the LG 11,800 BTU 230V Through-the-Wall Air Conditioner

What size room does the LG 11,800 BTU 230V Through-the-Wall Air Conditioner cool?: It is rated to cool a room up to 550 sq ft (11,800 BTU · 3.5 kW).
Do I need a professional to install the LG 11,800 BTU 230V Through-the-Wall Air Conditioner?: Not to replace a unit, but usually yes for a new opening. Sliding it into an existing wall sleeve it fits is a job you can do yourself (it is heavy, so plan on two people), with no refrigerant work. A new installation means cutting an opening through an exterior wall and fitting a sleeve, which is contractor work and usually needs a building permit. It runs on 230 volts, so it needs a matching 230-volt outlet on its own circuit, and adding one is a job for an electrician.