LG LW1821HRSM 18000 BTU Window Air Conditioner with WiFi — main product image

LG LW1821HRSM 18000 BTU Window Air Conditioner with WiFi

LG LW1821HRSM 18000 BTU Window Air Conditioner with WiFi

Name: LG LW1821HRSM 18000 BTU Window Air Conditioner with WiFi
Brand: LG
SKU: LW1821HRSM

★★★★★4.3 (1071 reviews)

18,000 BTU WiFi-enabled window unit with both cooling and supplemental heating for year-round comfort in rooms up to 1,000 sq. ft.

$994.81*

✓ In Stock on Amazon.com

View on Amazon

*Price sourced from Amazon.com. Last updated:Jul 15, 2026.Price and availability are subject to change.

Affiliate Disclosure: Studio Supplies may earn a commission from qualifying purchases made through links on this page, at no additional cost to you. This helps support our editorial team.

Notice a mistake? Let Us Know

Overview

The LG LW1821HRSM is a high-capacity window air conditioner that goes beyond basic cooling by adding supplemental heat and full WiFi smart controls. With 18,000 BTU of cooling power, it is built to maintain comfortable temperatures in medium to large rooms up to 1,000 square feet, making it suitable for open-plan living areas, large bedrooms, or office spaces. The supplemental heating mode provides warmth during transitional seasons, giving the unit genuine year-round utility without needing a separate heater for mild cold snaps.

LG ThinQ technology connects the unit to your home WiFi network, enabling remote control through the smartphone app from anywhere. Integration with Amazon Alexa and Google Assistant adds hands-free voice control for adjusting temperature, changing modes, and setting schedules. The 24-hour timer lets you program the unit to match your daily routine, while 4-way air deflection distributes conditioned air evenly throughout the room. The auto restart feature ensures the unit powers back on with its previous settings after an outage, so you return to a comfortable space even if you were away. Two cooling, heating, and fan speeds provide basic customization for different comfort levels and energy preferences.

Key Features

Control Your Air Conditioner from Anywhere: LG ThinQ technology allows you to control your air conditioner remotely with your phone, or use Amazon Alexa and Google Assistant for voice commands to adjust settings on the go

Supplemental Heat for Year-Round Comfort: Add warmth on cooler days with the supplemental heat option, making this unit perfect for both heating and cooling throughout the year

Customizable Cooling & Heating: With 2 cooling, heating, and fan speeds, plus a 24-hour timer, you can personalize your comfort with ease and create the perfect schedule for your space with LG's Heat and Cool Window Air Conditioner

Auto Restart After Power Outages: The auto restart feature automatically turns your air conditioner back on after a power failure, ensuring your space stays comfortable without interruption

Ideal for Medium to Large Rooms (Up to 1,000 Sq. Ft.): This 18,000 BTU unit is perfect for cooling and heating rooms up to 1,000 sq. ft., providing efficient temperature control for medium-sized spaces

Specifications

Brand

Model

LW1821HRSM

Cooling Capacity

18,000 BTU

Room Coverage

Up to 1,000 Sq. Ft.

Supplemental Heat

Yes

Smart Technology

LG ThinQ with WiFi

Voice Control

Amazon Alexa, Google Assistant

Fan Speeds

2 Cooling, 2 Heating, 2 Fan

Air Deflection

4-Way

Timer

24-Hour Programmable

Auto Restart

Yes

Pros & Cons

👍 Pros

Built-in WiFi with LG ThinQ app and voice assistant compatibility allows full remote control
Supplemental heat mode extends usefulness beyond summer cooling into cooler seasons
18,000 BTU capacity covers large rooms up to 1,000 sq. ft. effectively
Auto restart after power outages maintains comfort without manual intervention
24-hour programmable timer lets you schedule operation around your daily routine

👎 Cons

At 18,000 BTU, this unit requires a 230V/208V outlet, which may need professional electrical installation
Window-mounted design blocks a significant portion of the window opening
Only two fan speeds per mode limits fine-tuning of airflow compared to units with more speed options
Supplemental heat is not a replacement for a primary heating system in very cold climates

Frequently Asked Questions

Can this unit both heat and cool a room?

Yes, the LW1821HRSM includes supplemental heat in addition to cooling, so you can use it for warmth on cooler days and air conditioning during warmer months.

How do I control this air conditioner remotely?

You can use the LG ThinQ smartphone app over WiFi to adjust temperature, fan speed, and scheduling from anywhere. It also responds to voice commands through Amazon Alexa and Google Assistant.

What size room can this unit handle?

With 18,000 BTU of cooling capacity, it is rated for rooms up to 1,000 square feet.

Does the unit restart automatically after a power outage?

Yes, the auto restart feature restores the unit to its previous settings when power is restored, so you do not need to manually turn it back on.

How many fan speed settings does this air conditioner offer?

It provides 2 cooling speeds, 2 heating speeds, and 2 fan-only speeds, along with 4-way air deflection for directing airflow where you need it.