The best air conditioner depends first on what you need to cool: one room, several zones, or the whole home. For a single enclosed space, compare correctly sized window or through-the-wall units. For whole-home cooling, consider a central split or packaged system; a ductless mini-split may suit a zoned layout. Then compare the right efficiency rating for that equipment type and get the capacity and installation right.
This guide uses U.S. Department of Energy (DOE) guidance for U.S. homes. It does not rank individual models: the available evidence does not establish current product rankings, prices, or local rebates.
Choose the type of air conditioner for the area you need to cool
Room air conditioners and central systems serve different needs and are evaluated differently. Decide on the coverage before comparing efficiency numbers or shopping for equipment.
| Type | Best suited to | What to compare | Important cautions |
|---|---|---|---|
| Window or through-the-wall room unit | One enclosed room or a targeted cooling need | Capacity appropriate to the room, CEER among comparable units, and physical fit | DOE’s room-unit guidance covers window and through-the-wall units, not portable units. A unit must suit the opening and be installed as directed. |
| Central split or packaged system | Whole-home cooling where the home has compatible distribution | Capacity based on a load calculation, SEER2, regional ENERGY STAR criteria, and installation and duct condition | The cited DOE FEMP guidance applies to specified single-phase systems below 65,000 Btu/h, with exclusions; it does not cover every central product. |
| Ductless mini-split or multi-split | Zoned or ductless cooling where a split configuration fits the home | Load and zone sizing, applicable efficiency rating, configuration, and installation | Some mini- and multi-split systems are classified as central systems for regulatory purposes; models and configurations are not interchangeable. |
DOE describes room air conditioners in its room air conditioner guidance and central systems in its central air conditioner guidance. Its explanation of ductless mini-split heat pumps covers why some split configurations are treated as central systems.
The Tool Desk
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- Three-in-One Unit: Our 14,000 BTU ASHRAE (10,200 BTU SACC) air conditioner also functions as a dehumidifier & fan. This portable air conditioner has a full function remote control & top mounted control panel with LED display
- Portable AC: Take this personal air conditioner (16.5” x 14.06” x 27.09) in rooms up to 700 sq. ft. Stay cool in the hot summer months and sleep well with this BLACK+DECKER ac unit for bedroom
- Smart AC with Voice Control: This smart air conditioner allows Wi-Fi connectivity and can be controlled using our mobile app available on iOS and Google Play stores, and voice controlled by Amazon Alexa or Google Assistant
- Follow Me Remote: Our portable AC unit comes with a full function remote control that features a FOLLOW ME function, which allows the remote to act as a thermostat for precise temperature control
- Installation Kit: When it comes to fans that blow cold air, this indoor ac unit includes an easy-to-install window kit. A large, vented airflow outlet ushers in cool air
Size the equipment to the cooling load
For a room unit, avoid oversizing
Use the room and the manufacturer’s capacity guidance to choose an appropriately sized window or through-the-wall unit. A larger unit is not automatically a better choice: DOE warns that oversizing can increase purchase and energy costs while reducing humidity removal, because the unit may cycle on and off too often. As DOE puts it, “Select room air conditioners that are an appropriate size for the spaces to be cooled.” See its room air conditioner purchasing guidance for sizing and buying considerations.
For central and ductless systems, request a load calculation
Do not choose whole-home capacity from a simple square-foot rule of thumb. The home’s heating and cooling loads determine the required capacity. DOE Building Science Education says, “To right-size an HVAC system, you must first accurately determine both the heating and cooling loads.” It identifies ACCA Manual J as a recognized residential load-calculation method. Ask a qualified HVAC professional for a calculation appropriate to the home and system configuration; DOE explains the principle in its HVAC sizing guidance.
Rank #2
- 3 IN 1 COMFORT - The Midea EasyCool Window Air Conditioner unit has three modes to help your house, apartment, office, or room be as comfortable as possible. It can cool a space up to 150 sq. ft. quickly, circulate air with its 3-speed fan, or reduce humidity utilizing the dehumidifier mode.Controller type:Remote Control.
- QUIET & EASY TO USE - This window AC unit is low as 52dB(low mode). The intuitive LED display and remote control (batteries included) allow easy setting of time, temperature, and mode from across the room. The removable and reusable air filter protects your family and living space from dust and pet hairs.
- EASY INSTALLATION - Install easily in your home or apartment's existing window frame . All mounting accessories are included. A screwdriver is required (but not included) for installation. For some window frames, pilot holes are recommended before installing screws. Installation instructions are simple and setting it up is a breeze.
- WORLDWIDE LEADER - Midea is the air treatment brand with a motto to help make customers feel at home with each of their products. As a testament to our dedication to quality and our customers, we offer one-year parts and labor warranty on this product.
- ENERGY EFFICIENT - The EasyCool window air conditioner helps save you money throughout the year. There are also multiple custom settings to help you be even more energy-efficient like Eco mode and an EasyTimer feature to program a schedule that fits your needs.
Compare efficiency using the rating for that equipment
Use CEER to compare room air conditioners with other room units, and SEER2 to compare applicable central systems. These are different metrics; a CEER figure should not be compared directly with a SEER2 figure. Central-system ENERGY STAR criteria also vary by U.S. region, so check the criteria that apply where the home is located.
DOE’s 2024 room-unit example used December 2024 product data. For a room air conditioner without reverse cycle, with louvered sides, and a capacity from 8,000 to 13,999 Btu/h, DOE compared 15.4 CEER for its “best available” example, 14.7 CEER for the ENERGY STAR case, and 10.9 CEER for a less-efficient comparison. Its modeled 12,000 Btu/h unit ran 750 hours per year, with annual energy use of 584, 612, and 826 kWh, respectively. DOE used a nine-year lifetime and stated assumptions; these figures describe that scenario, not every home or product. Details are in the DOE room-unit guidance.
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Rank #3
- Effortless Cooling: Achieve optimal comfort with customizable temperature settings and two fan speeds; Effortless Temperature Control helps to maintain your preset temperatures for consistent comfort
- Easy Maintenance: Keep your air conditioner running efficiently with the easy-to-clean washable filter, designed to capture dust from the air for long-lasting performance
- Undisturbed Comfort: Experience a peaceful home environment with a quiet performance at 52 dBA – ideal for bedrooms or small spaces up to 150 sq. ft.
- Effortless Convenience: Benefit from the Auto Restart feature, which automatically restores the unit's previous settings once power is restored to the window air conditioner
- Hassle-Free Operation: The extra-long three-prong power cord eliminates the need for extension cords, while the adjustable side panels easily extend to best fit your window, ensuring a secure installation with optimal efficiency and airflow
For central systems, DOE’s 2024 FEMP example, based on December 2024 efficiency levels, listed 23.5 SEER2 for its “best available” example, 15.2 SEER2 for the ENERGY STAR case, and 13.4 SEER2 for its less-efficient comparison. These are example values, not a complete market ranking or a universal recommendation. The guidance’s model uses 11 cents per kWh, citing the average electricity price at federal facilities throughout the United States as of July 2024; that is an input to the model, not a current residential rate.
Estimate costs using your home and local conditions
Efficiency ratings alone do not determine what a system will cost to operate. Compare the equipment and installation quotes with your local electricity rate, expected hours of use, and climate. DOE’s central-system example estimated lifetime energy-cost savings for its ENERGY STAR comparison of $1,853 in the Southeast, $869 in the Southwest, and $927 in the Northern region. Those regional estimates use DOE’s assumptions and different modeled lifetimes—18, 25, and 24 years, respectively—so they are not promised savings for an individual household. See the DOE central-system guidance for its assumptions.
Rank #4
- BEST FOR SMALL ROOMS: Cools up to 150 sq ft efficiently with 5,000 BTU cooling power. Ideal for bedrooms, home offices, dorm rooms, workshops, and studio apartments. Compact 16.4" W x 13.4" D x 12.6" H design fits tight spaces.
- QUIET OPERATION - Quieter than many older window AC units, with 2 cooling modes (low 52 dBA for nighttime, high 56 dBA for rapid cooling) and 2 fan speeds for personalized comfort. Simple mechanical controls mean no annoying digital beeps.
- SIMPLE, RELIABLE MECHANICAL CONTROLS: Easy-to-use dials for temperature and fan speed—no Wi-Fi, apps or complex setup required. 10 temperature settings let you dial in your perfect comfort level. Auto restart after power outages.
- LOW MAINTENANCE & ENERGY SMART: No manual draining under normal conditions. Washable, reusable filter for easy care. Low 440W power draw helps reduce energy costs compared to older, inefficient units.
- EASY DIY INSTALLATION: Fixed chassis installs easily and fits double-hung windows 27.125"–36" wide and 13.375" high minimum. EZ Mount kit with foam insulation included. Backed by 1-year GE limited warranty for peace of mind.
Some utilities offer incentives, but availability depends on location and can change. Check with the local utility and use ENERGY STAR’s Rebate Finder to look for current programs. Do not treat an incentive as available until its terms and eligibility are confirmed.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Installation quality affects comfort and performance
For central systems, a suitable rating cannot compensate for poor installation. DOE identifies oversized equipment, improper refrigerant charging, and leaky ducts as problems that can reduce efficiency and comfort and shorten equipment life. Ask the installer to explain the load calculation, the proposed equipment and its rating, and how duct condition and refrigerant charge will be addressed. DOE discusses these installation considerations in its central air conditioner guidance.
Best Value
- Three-in-One Unit: Our 10,000 BTU (5,550 DOE) air conditioner also functions as a dehumidifier & fan. This portable air conditioner has a full function remote control & top mounted control panel with LED display
- Portable AC: Use this personal air conditioner (15.3” x 14” x 24.8") in rooms up to 450 sq. ft. Stay cool in the hot summer months and sleep well with this BLACK+DECKER ac unit for bedroom
- Follow Me Remote: Our portable AC unit comes with a full function remote control that features a FOLLOW ME function, which allows the remote to act as a thermostat for precise temperature control
- Easy Mobility: Thanks to casters on the bottom and side handles on both sides of the small air conditioner, this air cooler can be moved from room to room without any hassle
- Installation Kit: When it comes to fans that blow cold air, this indoor ac unit includes an easy-to-install window kit. A large, vented airflow outlet ushers in cool air
For a room unit, confirm that the window or wall opening can accommodate the selected form factor and follow the manufacturer’s installation directions. When replacing or retiring an old room air conditioner, arrange proper refrigerant recovery and disposal; DOE points to EPA safe-disposal requirements.
Quick Recap
A practical buying sequence
- Define the coverage. Choose between one-room cooling, zoned cooling, and whole-home cooling before comparing products.
- Confirm the configuration. Check whether a window or through-the-wall unit fits, or whether the home can support the distribution and installation a central or ductless system requires.
- Size for the space or load. Use manufacturer guidance for a room unit; request a heating and cooling load calculation for a central or ductless system.
- Compare like with like. Compare CEER among room units and SEER2 among applicable central systems, and check region-specific ENERGY STAR criteria where relevant.
- Review total cost and installation. Consider equipment, installation, local electricity rates, expected use, climate, duct condition, and any verified local rebate.
- Plan for replacement responsibly. Confirm refrigerant recovery and disposal when retiring old equipment.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
