The best air conditioner for a small apartment is the one that fits the opening you can use and is correctly sized for the room or zone you want to cool. For many apartments, that means a window unit; a through-the-wall unit may suit a dedicated sleeve. A portable air conditioner is a separate category with different installation needs and efficiency information, so compare it on its own terms.
Choose the format that fits your apartment
Room air conditioners cool a room or small zone rather than an entire apartment. Decide where you need cooling, then check what the building and opening allow before comparing products.
Window air conditioner
A window unit can be a practical choice when the window design, opening dimensions, and apartment rules permit installation. Confirm the manufacturer’s required opening size, support, clearances, and installation method. Do not assume that every unit fits every window.
Through-the-wall air conditioner
A through-the-wall unit is intended for a compatible wall opening or sleeve. Verify the exact dimensions and installation requirements, and check whether the apartment permits the work. A window model and a wall model are not automatically interchangeable.
#1 Best Overall
- PERFECT FOR SMALLER ROOMS - Midea's Affordable Window AC unit is perfect to help your room be as comfortable as possible. It can cool 150 sq. ft. with 7 temperature settings, 2 cooling/2 fan-only speeds, and 2-way air direction to give you the perfect amount of cooling every time.
- ENERGY EFFICIENT- Midea's 5,000 BTU window air conditioner has a Combined Energy Efficiency Rate (CEER) of 11.0 which helps reduce the energy costs to save you money throughout the year.
- QUIET & EASY TO USE - This window AC unit is quieter than a household refrigerator. It also features easy-to-use mechanical controls to quickly set the time, temperature, and mode and has a removable & reusable air filter.
- EASY INSTALLATION - Easily install in your home or apartment's existing window frame. Suitable for windows 23''-36'' wide and minimum 13'' high. 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. Please see included instruction manual for further detail.
- WARRANTY: 1 Year Parts & Labor Warranty comes with each Midea product to ensure the quality of our brand to our customers. Our team is happy to help if any questions or issues arise and make sure to register your product on our website for even faster support in the future.
Portable air conditioner
Portable units are a distinct product category, not simply window units on wheels. They commonly require an exhaust connection at a window, so check the exact model’s installation instructions, capacity rating, and category-specific efficiency information. The U.S. Department of Energy’s federal efficiency guidance for room air conditioners excludes portable air conditioners; do not use that guidance to treat portable and window-unit efficiency figures as directly equivalent. See DOE’s portable air conditioner overview.
What size air conditioner do you need?
Size the unit for the room or zone it will actually cool, not simply for the apartment’s total square footage. Follow the manufacturer’s sizing guidance and account for the layout and conditions in the target space. An open-plan apartment may not cool evenly from a unit placed in one room.
DOE FEMP advises buyers to “Select room air conditioners that are an appropriate size for the spaces to be cooled.” Its guidance warns that oversizing can increase purchase cost and energy use and impair humidity removal because the unit cycles on and off too frequently. See DOE FEMP’s room air conditioner guidance.
Rank #2
- 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.
Compare capacity, efficiency, and fit
Once the format is settled, compare the current specifications for the exact product. A useful shortlist checks:
Recommended Free Tools
- Cooling capacity: Confirm that the product is intended for the room or zone you plan to cool.
- Efficiency information: Compare ratings only within the relevant product category and rating basis. DOE FEMP points buyers to ENERGY STAR product information for covered room air conditioners.
- Dimensions and clearances: Measure the opening and check the unit’s dimensions, required support, and manufacturer-specified clearances.
- Installation requirements: Review the manual and confirm that the window, wall sleeve, electrical setup, and building rules work for that model.
- Cost: Compare purchase price with likely operating cost for your use. Actual energy cost depends on the unit, how often it runs, and local electricity rates.
DOE FEMP’s December 2024 guidance gives illustrative efficiency and cost figures for particular room-air-conditioner configurations and capacity bands. Its ENERGY STAR example lists a CEER of 14.7, estimated annual use of 612 kWh, and annual energy cost of $67; its best-available example lists a CEER of 15.4, 584 kWh, and $64. The same page estimates nine-year lifetime energy-cost savings of $167 and $189, respectively, versus its less-efficient example. These are calculations under the page’s stated assumptions, not forecasts for a particular apartment or claims about every current product. Check current product details rather than choosing from those examples alone.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Installation matters as much as the rating
A poorly fitted room air conditioner can let air leak around the installation, reducing comfort and wasting energy. DOE’s Home Cooling infographic cautions that improper installation can increase air leakage. Follow the model’s instructions for securing and sealing the unit, and get the landlord or building manager’s approval where required. If the window or wall opening cannot meet the manufacturer’s directions, choose a compatible format rather than improvising an unsafe or leaky fit.
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
Check current product and local information
Product specifications, availability, and prices can change. Before buying, confirm the exact model’s capacity, dimensions, installation method, and efficiency category with its manufacturer or current product listing. DOE FEMP notes that some utilities offer rebates; eligibility and availability vary by location, so check with your utility before counting a rebate toward the cost.
DOE projected that finalized federal standards would save consumers approximately $1.5 billion per year on electricity bills and avoid 106 million metric tons of carbon dioxide over 30 years. Those are agency projections associated with the standards, not savings attributable to an individual air conditioner purchase. See DOE’s March 23, 2023 announcement.
Free tools Windows power users keep installed
One-click scans. No signup required.
Quick Recap
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.
