10 Best Coldest Air Conditioner 2025 in the United States

The DELLA 28K BTU Tri Zone Mini Split AC is a strong choice if you need cooling and heating for up to three rooms, covering about 1200 square feet in total. It has three indoor units, each with 9000 BTU capacity, which can be controlled separately, giving you personalized comfort in each space. Thanks to its DC inverter technology and a high 20 SEER rating, it is very energy efficient, potentially saving you around 30% on power compared to traditional units. Plus, it works well even in cold weather, down to about 5°F, making it suitable for cold regions.

The system operates quietly at around 41 decibels, which is about the noise level of a quiet library, so it won’t disturb your peace. It also includes useful features such as Alexa compatibility, sleep mode, multiple fan speeds, and a dry mode to reduce humidity. The airflow can be adjusted in four directions for even cooling or heating.

On the downside, the unit does not support a self-cleaning function despite the button appearing on the controller, which means you’ll need to maintain it manually. Installation is complex and requires professional help, so it's not a DIY project. The package includes a full installation kit but keep in mind that any changes to pipe length during installation require refrigerant adjustments, adding to the complexity. This air conditioner is well suited for homeowners looking for multi-room cooling and heating with good energy efficiency and quiet operation, especially in cooler climates. It is less suited for those wanting a simple, self-maintaining system or an easy DIY setup.

The BLACK+DECKER Smart Portable Air Conditioner with Heat offers a decent cooling capacity of 10,000 BTU DOE (14,000 BTU ASHRAE 128) which is effective for rooms up to 375 square feet. However, the unit claims to be suitable for areas up to 700 square feet, which might be optimistic for optimal performance. The added heating function with 12,000 BTU makes it versatile for year-round use. It includes a smart control feature with Wi-Fi connectivity, allowing control via mobile app and voice commands with Amazon Alexa or Google Assistant, adding convenience for tech-savvy users. The 'Follow Me' remote control enhances temperature accuracy by acting as a thermostat.

Energy efficiency is on the lower side with a SEER of 6.2 and it is not Energy Star rated, which may result in higher energy bills. The noise level of 54 dB is relatively standard for portable units, but may still be noticeable, especially during nighttime. The unit's design includes an easy-to-install window kit, making setup straightforward. Weighing 35 pounds, it's fairly portable and does not require assembly.

This air conditioner would be suitable for those looking for a portable, versatile unit with smart features, best used in moderately sized rooms rather than large spaces.

The Della 36K BTU Quad 4 Zone mini split air conditioner is a powerful and versatile option for cooling large spaces up to 1750 Sq. Ft. It features a high cooling capacity with 36,000 BTU and effectively serves multiple rooms thanks to its four indoor air handlers, which all have separate controls, allowing for individualized climate settings in each room. The energy efficiency is commendable with a SEER rating of 19, and it uses DC Inverter technology, promising up to 30% power savings. This makes it a cost-effective choice in the long run.

Additionally, it is compatible with Alexa, offering convenient control through voice commands and WiFi connectivity for remote access to settings and functions. With its ultra-quiet operation at just 41 dB, it ensures a peaceful environment, which is a significant advantage for residential settings. Multiple fan speeds and smart functions such as 4D airflow, sleep mode, eco energy saving mode, and a 24-hour timer add to its user-friendly design.

However, it’s worth noting that the installation requires professional assistance due to the need for line-set vacuuming and potential adjustments to freon levels, which can be an additional cost. Furthermore, the self-cleaning function indicated in the display is not operational, which might confuse some users. Despite these minor drawbacks, the Della 36K BTU air conditioner reflects its reliability and performance.