WindowENERGY STAR

LG LW1521ERSM 15,000 BTU

4.4(3,100 retailer ratings) by LG · Model LW1521ERSM

The go-to large-room smart unit: 15K BTU, Wi-Fi via ThinQ, and whole-floor coverage to 800 sq ft.

Cooling

15,000 BTU

Covers

800 ft²

Efficiency

11.8CEER

Noise

53 dB

$549 est.

typical street price · via Amazon

Check Price

Is 15,000 BTU right for your room? Run the sizing calculator

Strengths & trade-offs

Pros

Cools up to 800 sq ft
ThinQ app and voice control
4-way air deflection

Cons

Needs a large window
Heavy 100+ lb install

What the LG LW1521ERSM 15,000 BTU costs to run

Estimated from this unit's 11.8CEER rating at 8 hours/day of cooling, using average residential electricity rates for each US climate zone. Your usage and utility rate will shift these numbers — run the calculator for your exact room.

Climate zone	Example regions	Est. cost / month
Cool North	Pacific NW, Upper Midwest, New England	$49 /mo
Mixed / Temperate	Mid-Atlantic, Midwest, Mountain	$52 /mo
Hot & Humid	Southeast, Gulf Coast, Texas	$43 /mo
Hot & Dry	Southwest, Desert	$46 /mo

Full specifications

Type	Window air conditioner
Cooling capacity	15,000 BTU
Rated coverage	800 ft²
Efficiency	11.8 CEER
Noise (low)	53 dB
Smart features	App, Voice, Scheduling
ENERGY STAR	Yes
Model number	LW1521ERSM
Typical street price	$549