10 Best Air Conditioners Air Conditioners 2026 in the United States

The Daikin Oterra Series 18,000 BTU ductless mini-split is a strong choice if you're looking to cool and heat a medium-sized area, around 1,000 square feet. It offers excellent energy efficiency with a high SEER2 rating of 21 and an EER2 of 12.0, which means it will help keep your electricity bills lower compared to many standard units. This model uses the eco-friendly R32 refrigerant and has a heat pump function, making it useful year-round, even in cooler climates down to about 5°F for heating and up to 122°F for cooling.

The unit includes smart features like automatic defrosting to prevent ice buildup and an air purifying filter that can improve indoor air quality. The included installation kit and wall bracket make setup more straightforward, but because it’s a mini-split system, professional installation is generally needed. Daikin units are typically known for quiet operation, which is advantageous for living spaces.

While the upfront cost and installation might be higher than window or portable ACs, this model is best suited for homes or rooms without existing ductwork. For those seeking durable, energy-efficient cooling and heating with advanced features, especially in areas where duct installation is impractical, this Daikin model presents a reliable and effective option.

The Daikin Oterra Series 24,000 BTU mini-split is a strong choice for cooling and heating spaces up to about 1,500 square feet. With a cooling power of 22,400 BTU (variable between 7,000 and 26,400 BTU) and heating capacity up to 23,600 BTU, it offers flexible temperature control thanks to its DC inverter technology. Its high energy efficiency is notable, boasting a 21 SEER2 rating and excellent EER of 12.0, which means it uses less electricity while keeping your space comfortable year-round. This makes it a smart pick for those wanting to save on energy bills while staying cool or warm.

The unit works well in a wide range of temperatures, from freezing cold to hot, making it suitable for different climates and various rooms like basements, sunrooms, or garages where traditional ACs aren't practical. It includes features like an anti-corrosion heat exchanger, automatic defrost, and a washable air filter, which help the system last longer and keep air quality high. The package comes ready with installation parts and a remote control, simplifying setup.

If you are looking for an energy-efficient, versatile ductless solution with strong heating and cooling abilities, the Daikin Oterra is a solid option, especially for medium-sized rooms and homes aiming for comfort and savings.

The Frigidaire 12,000 BTU Window Air Conditioner is designed to cool medium to large rooms, up to about 550 square feet, making it a good fit for living rooms, larger bedrooms, or small offices. Its 12,000 BTU cooling capacity is effective for this space size, providing enough power to keep the area comfortable. The unit operates quietly at around 57 decibels, which is about the noise level of a normal conversation, so it won’t be too disruptive when running. It offers three fan speeds and 6-way directional airflow, allowing you to customize the cooling to your liking. Energy efficiency is decent, with a Seasonal Energy Efficiency Ratio (SEER) of 10.9, and features like Eco Mode and Sleep Mode help lower electricity use by adjusting cooling as needed. This can save money on energy bills if used properly.

The air conditioner also includes helpful features such as a washable dust filter with a light reminder for cleaning, a remote control for easy operation, and a 24-hour timer to match your schedule. It even has a Dry Mode to reduce humidity, which can improve comfort on muggy days. Installation is straightforward since it is a window unit, but keep in mind it weighs about 63.5 pounds, so some effort is needed to mount it securely. One limitation is the relatively short 1-year manufacturer warranty, which might be a concern for long-term reliability. While 57 dB is quiet for an AC, it’s not whisper silent, so very noise-sensitive users might notice it. This model delivers solid cooling performance with convenient energy-saving and comfort features, making it a practical choice for those seeking a reliable window air conditioner for medium-sized spaces.