10 Best Efficient Window Air Conditioner 2025 in the United States

The LG 23,000 BTU window air conditioner is a strong contender for cooling medium to large rooms up to about 1,440 square feet, making it suitable for spacious living areas or offices. Its high cooling capacity means it can quickly and effectively lower temperatures in bigger spaces. One useful feature is its supplemental heat option, so it can provide warmth during colder months, which adds versatility beyond just cooling. It includes two fan speeds for better airflow control and has electronic controls with a remote, making it easy to adjust settings from anywhere in the room.

Installation-wise, the slide in-out chassis should simplify placing and removing the unit in a window. However, it operates at 64 decibels, which is on the louder side compared to some quieter models, so it might be noticeable in very quiet environments. The energy efficiency ratio (EER) is 9.8, which is moderate—not the most efficient but acceptable for the size and power it delivers. While the product includes a dehumidifier function and auto-restart after power outages, the warranty is only one year, which is fairly typical but worth considering for long-term durability.

This LG model is well suited for those who need a powerful, year-round solution for larger spaces and are willing to accept a bit of noise and moderate energy consumption.

The Amazon Basics 5000-BTU Window Air Conditioner is designed for small rooms up to 150 square feet, making it a good fit for bedrooms, home offices, or other small spaces. With 5000 BTU cooling power, it provides enough cooling for these areas without consuming excessive energy, supported by a decent energy efficiency rating (SEER of 14). It offers flexible comfort options including 7 temperature settings, 2 fan speeds, and adjustable air direction, which helps tailor the airflow to your preference. The unit features a washable filter that is easy to clean and helps reduce dust and allergens, which is a useful bonus for maintaining air quality.

Installation is straightforward for standard windows between 23 and 36 inches wide with a basic mounting kit included, though you’ll need a screwdriver as it’s not supplied. Noise-wise, it operates quietly at around 56 dB, suitable for use in bedrooms or workspaces where low noise is appreciated. The cooling capacity limits it to smaller rooms only, so it wouldn't be ideal if you need to cool larger spaces. Also, it lacks advanced features like a remote control or smart connectivity, which some may expect in modern units.

Its size is compact, making it less intrusive once installed, and the simple mechanical controls keep operation easy for anyone. This unit is a practical and affordable choice if you need efficient cooling in a small room and prefer a basic, user-friendly window AC without extra bells and whistles.

The Whirlpool 18,000 BTU window air conditioner is a strong choice for cooling large areas up to about 1,000 square feet. With a powerful cooling capacity, it is well-suited for bigger rooms like living rooms or apartments. It includes a supplemental heater, which is useful for mild chilly days, though it is not intended as a main heat source in very cold weather. The unit’s energy efficiency is decent, featuring a SEER rating of 10.7, which means it offers reasonable running costs though it is not the highest efficiency available.

Noise level is around 56 decibels, which is moderate—noticeable but not overly loud—making it suitable for bedrooms or living spaces without causing disruption. Installation is straightforward due to a quick-mount kit, but the window must be at least 19.5 inches tall, so window size should be checked beforehand. Additional features include an electronic control panel with multiple fan speeds, eco and sleep modes, and a 24-hour timer for convenience. The reusable washable filter helps maintain clean air and unit efficiency over time, and the included remote control allows for easy adjustments without needing to get up.

One consideration is its weight of nearly 109 pounds, which can make installation challenging for one person. Additionally, the 1-year warranty is somewhat limited in comparison to some competitors. For those seeking a powerful, relatively efficient window AC with extra heating and convenient controls for large rooms, this Whirlpool model represents a reliable option.