Window air conditioners are an affordable and efficient way to cool individual rooms. They’re efficient and relatively inexpensive compared to installing central air conditioning. Understanding how window air conditioners work can help you decide whether they meet your cooling needs.
Window air conditioners are self-contained systems that cool small to medium-sized spaces. They work by extracting warm air from the room and cooling it through refrigeration before circulating the colder air back into the space. They won’t cool your whole house but work well in spaces like a bedroom with a closed door. If you’re renting, they’re a good solution for keeping your space comfortable.
How Window AC Units Operate
Window air conditioners operate on a simple principle of heat exchange, sending heat out of the room and returning cooler air into the house. When you turn the unit on, the thermostat monitors the room temperature. The compressor starts once it registers that the air is too hot or above your set level.
The evaporator blower draws warm room air through the air filter and over the cooling coil. The cooling coil absorbs the air’s heat, lowering its temperature and humidity. Cooled and dehumidified air is then blown back into the room. On the outdoor side, the condenser coil releases the absorbed heat to the outside.
This cycle continues until the room reaches the desired temperature you set on the thermostat. To prevent damage to fans and motors, most units have a built-in cool-down period of about three minutes before the compressor can restart. The hotter the air inside the house, the harder it is for your unit to cool the air.
Related: What is a Fan Speed Controller?
Choosing the Right Window AC Unit
Take these factors into account when choosing a unit for your space:
BTU Ratings
The most critical factor in selecting a window AC unit is its BTU (British Thermal Unit) capacity. You need about 20 BTUs per square foot of living space. Here’s a quick guide:
- 150-250 square feet: 5,000-6,000 BTUs
- 250-350 square feet: 7,000-8,000 BTUs
- 350-450 square feet: 9,000-10,000 BTUs
- 450-55 square feet: 12,000 BTUs
A unit that’s too small means your space won’t be adequately cooled, and you’ll use excessive energy as your unit works overtime. An oversized unit may cool the room quickly but fail to dehumidify the air, making your room feel clammy.
Energy Efficiency
When shopping for a window air conditioner, look for units with high Energy Efficiency Ratio (EER) ratings. The higher the EER, the more efficient the unit and the lower your electric bill. ENERGY STAR-certified models are good choices for energy-conscious homeowners who want to reduce their environmental footprint and save on utility bills.
Installation and Maintenance
Proper installation and regular maintenance ensure window air conditioners’ optimal performance and longevity.
Installation Tips
Proper installation ensures your window AC works efficiently and effectively from the start. Choose a window that can support the unit’s weight, and that’s near an electrical outlet to avoid using extension cords, which are a trip hazard. Use weatherstripping to seal gaps around the unit, preventing air leaks.
When installing the unit, put it in the window with a slight tilt toward the outside for proper drainage. If the unit is tilted inward, water can pool under it and rot your windowsill. Always follow the manufacturer’s instructions carefully for safety and efficiency.
Maintenance Best Practices
Regular maintenance keeps a window air conditioner in good working order. Clean or replace the air filter monthly during the cooling season to maintain airflow efficiency. A clogged filter reduces cooling effectiveness and strains the unit.
Check and clean the drain pan at least once a month. Mold and mildew can grow in standing water, so make sure the drain pan is clear and draining properly.
Clean the evaporator and condenser coils annually, as dirty coils can impede heat exchange.
When the hot season is over, cover and store your AC unit in a protected location.
Energy Saving Tips for Window AC Users
Maximizing energy efficiency helps the environment and saves you money.
Use a programmable thermostat that will adjust temperatures automatically when you’re away or sleeping to avoid unnecessary cooling. Close curtains during the hottest parts of the day to prevent heat gain from sunlight. Sealing air leaks around windows and doors prevents cooled air from escaping and reduces the workload on the AC unit.
To make it even easier on the unit, use ceiling fans to circulate cool air so you can set the thermostat higher on your window unit without losing comfort. Conduct regular maintenance to keep your unit functioning at peak performance and to avoid energy waste.
Heat Pump Window Air Conditioner: A Versatile Option
Heat pump window air conditioners are a versatile solution for homeowners—these units can cool in summer and heat in winter, providing year-round comfort. They also spare your back the pain of removing a window unit in the fall and carrying it down to the basement.
How Heat Pump Window ACs Work
Heat pump window air conditioners have a reversing valve to switch between cooling and heating modes. In cooling mode, they function like standard AC units. In heating mode, the unit extracts heat from outdoor air, even when temperatures are low, and transfers it inside, effectively warming the room. These units can be more energy efficient and cost effective than separate heating and cooling appliances, but they won’t heat below certain temperatures.
Benefits of Heat Pump Technology
Heat pump technology provides a convenient and compact air temperature control solution, offering significant energy bill savings. If you bought an older home with radiators, adding the ductwork and grates necessary for HVAC is prohibitively expensive. Heat pumps are ideal for space-limited environments where a full HVAC system may not be viable.
Innovations and Future of Window Air Conditioners
New features and enhanced energy efficiency continue to transform window air conditioners. Industry innovations are leading toward smarter, more environmentally friendly solutions.
Smart Technology Integration
Many units now feature smart technology. Homeowners can control them remotely via smartphone apps or even voice commands through virtual assistants. This integration makes it easier to manage indoor temperatures, adjust settings, and monitor energy usage.
Environmentally Friendly Refrigerants
Manufacturers are increasingly using environmentally friendly refrigerants that contribute less to global warming. This shift meets regulatory requirements and aligns with sustainable practices, reducing carbon footprints and encouraging green living.
Improved Designs for Better Aesthetics
Manufacturers are working to develop sleeker, more compact models to fit seamlessly into your home’s profile without sacrificing performance.
Enhanced Noise Reduction
Noise is often a concern with window AC units. Newer models focus on reducing sound without affecting cooling efficiency through advanced materials and engineering techniques.
