Window air conditioners are designed to cool one or multiple rooms that don't have access to adequate cooling.
There are many things to consider when shopping for a window air conditioner, like size and maintenance. To learn more, here are 5 things to consider when shopping for a window AC:
- Cooling Capacity/Size Considerations
- Installation
- Electric Requirements
- Energy Efficiency
- Maintenance
1. Cooling Capacity
Cooling capacity should be your first consideration before buying a window AC. Cooling power is measured in British Thermal Units, or BTUs, per hour. For the best efficiency and effectiveness, stick with a unit that has a BTU level designed to fit your space. A window AC with not enough BTU power will run continuously trying to cool the space and, in the process, will eat up your energy budget and place undue wear on the unit. One that's too large won't cool and dehumidify your space evenly, leaving your room air susceptible to uncomfortable hot and cold pockets.
To find your ideal cooling capacity, calculate the size of the space you want cooled in square feet. Then use the chart below to find the right amount of BTUs.
| Window AC Sizing Chart | |
|---|---|
| Square Footage of Your Space | BTUs Needed (per hour) |
| 100 to 150 sq. ft. | 5,000 BTUs |
| 150 to 250 sq. ft. | 6,000 BTUs |
| 250 to 300 sq. ft. | 7,000 sq. ft. |
| 300 to 350 sq. ft. | 8,000 sq. ft. |
| 350 to 400 sq. ft. | 9,000 sq. ft. |
| 400 to 450 sq. ft. | 10,000 sq. ft. |
| 450 to 550 sq. ft. | 12,000 sq. ft. |
| 550 to 700 sq. ft. | 14,000 sq. ft. |
| 700 to 1,000 sq. ft. | 18,000 sq. ft. |
| 1,000 to 1,200 sq. ft. | 21,000 sq. ft. |
| 1,200 to 1,400 sq. ft. | 23,000 sq. ft. |
| 1,400 to 1,550 sq. ft. | 25,000 sq. ft. |
Ceiling Height: The above estimates assume you have traditional 8-foot ceilings. If your ceilings are higher than 8 feet, you'll want to increase your BTU level. To determine the most accurate BTU estimate, you should also consider these factors:
- Sunlight: If your room is sunny during the day, increase your BTUs by 10%.
- Shade: If your room is shaded for most of the day, decrease your BTUs by 10%.
- Number of Occupants: If more than 2 people will occupy the space regularly, add 600 BTUs of cooling power for each person.
- Kitchen: If you are installing your window AC in a kitchen, increase the number of BTUs by 4,000.
To view available window ACs for your space, check out these options:
- Small Rooms up to 350 square feet
- Medium Rooms between 350 and 700 square feet
- Large Rooms between 700 and 1,000 square feet
2. Installation
Most window AC models are designed to fit inside standard double-hung windows. However, many models can also be installed inside a custom-created wall space with special mounting hardware. This is a useful alternative if your window's dimensions don't work with the AC unit or if you don't have vertical sash windows.
- Window: Measure the dimensions inside the window frame exactly, paying special attention to the width. Find the minimum and maximum window width dimensions listed in the AC's specs. Don't worry if your model doesn't fit your window frame exactly. All window air conditioners come with installation kits, which include side curtains to seal off extra space on each side of the AC. For directions on how to install one in a window, check out our video on How to Install a Window AC.
- Wall: First make sure the model you want can be installed through the wall and that you have the appropriate installation kit. If the window AC can be installed in-wall, the owner's manual will have detailed instructions on the correct process. If necessary, consult a professional. You can view available window ACs that can also be installed through a wall here.
When completely installed, the window air conditioner will sit at a slight downward angle toward the back, with the exhaust system facing outside and the cooling system facing inside. Many window air conditioners feature a slide-out chassis in a rugged cabinet, or mounting sleeve, that stabilizes and secures the unit, which allows easy access to it for maintenance. All window air conditioners come with detailed, easy-to-follow instructions for installation.
3. Electrical Requirements
Because window air conditioners are more powerful than other common household appliances, make sure your existing electrical system meets the needs of the unit's electrical requirements. Most room air conditioners operate on 115V, 125V or 220V circuits.
- 115-125 Volts: ACs with cooling capacities below 15,000 BTUs usually run on standard residential (115V to 125V) circuits.
- 220 Volts: Window ACs with cooling capacities above 15,000 BTUs usually run on 220V circuits. With these models, you may need to install special electrical wiring or seek out an electrician to assist you.
Electrical requirements will be listed in the specifications. In addition, the correct plug face type may be pictured or listed by its NEMA (National Electrical Manufacturers Association) classification.
4. Energy Efficiency
In general, the best window air conditioners are a more economical choice than central air conditioners. They cost less to purchase and–if sized correctly–are cheaper to operate over the long-term. To gauge a unit's energy efficiency, look for two features:
- Energy Star Rated: Typically use approximately 10 percent less energy than comparable models and save money on operating costs. Most states offer rebates for customers who purchase an Energy Star model.
- EER (or Energy Efficiency Ratio): This tells you how many BTUs the unit uses for each watt of power. Use this as a rule of thumb: the higher the EER, the more efficient the air conditioner. According to the U.S. Department of Energy, you should shop for a room air conditioner that has an EER of at least 10.0 for the best energy & cost savings. Friedrich window air conditioners are known for both their high EER and Energy Star-qualified operation.
5. Maintenance
Window ACs require periodic maintenance to keep them in top condition. They can be vulnerable to outside dirt and debris, which can accumulate inside or on the back. Dust and particles will build up on the air conditioner's air filter over time. If left untreated, all of these things will eventually combine to reduce the effectiveness of your air conditioner.
To ensure long-lasting operation, clean it thoroughly at least once a year. A window AC with a slide-out chassis makes this easy because you just have to slide the unit out to clean it. Most air filters are washable with mild soap and water. For specific maintenance tips for your model, refer to your owner's manual.
For protection from pests, some room ACs, like the Friedrich Kuhl Series, are equipped with mosquito traps that allow condensation to flow outside without letting insects inside.
In Summary
A window air conditioner can be an effective, energy-efficient solution for rooms that don't have access to cooling or tend to be hotter than the rest of the house. Some units can be installed through the wall if no window is available, and all window units include an installation kit. Consider the size of the room to find the correct BTU rating to adequately cool it, and be sure to keep it maintained for years of cooling comfort.
Still Have Questions?
For more information on specific products and ways to improve your indoor environment, review our extensive product listings and other educational materials. Not sure what’s best for you? We can take the guess work out of decision-making. Contact our product experts toll-free at 1-800-934-9194. We want to help you make your indoor environment a healthy one.
