Room Air Conditioners

Room air conditioners cool individual rooms rather than the entire home, making them less expensive to operate than central units. While their efficiency is generally lower, they are ideal for cooling smaller spaces.

Energy Efficiency of Room Air Conditioners

  • Efficiency Measurement: The efficiency of a room air conditioner is measured by the Energy Efficiency Ratio (EER), which is the ratio of the cooling capacity (in BTU per hour) to the power input (in watts). The higher the EER, the more efficient the air conditioner.
  • New Standards: As of January 2023, new equipment uses the more stringent EER2 rating. Look for the ENERGY STAR® label when purchasing a new unit.

Sizing and Selecting a Room Air Conditioner

  • Cooling Capacity: The required cooling capacity depends on the room size. Room air conditioners generally range from 5,500 to 14,000 BTU per hour.
  • Proper Sizing: An oversized unit will cool the room too quickly without dehumidifying it properly, leading to discomfort. A smaller, properly sized unit running for a longer period operates more efficiently and effectively.
  • Calculation: Typically, you need 20 BTU for each square foot of living space. Consider room height, local climate, shading, and window size when selecting an air conditioner.

Electrical Requirements

  • Power Needs: Smaller units (less than 7.5 amps) can plug into any 15- or 20-amp, 120-volt household circuit not shared with major appliances. Larger units (more than 7.5 amps) require a dedicated 115-volt circuit, and the largest models need a 240-volt circuit.
  • Verification: Ensure your home's electrical system meets the unit's power requirements.

Additional Features to Consider

  • Directional Airflow: For corner installations, select a unit that can direct airflow as needed. For long rooms, look for fan controls with "Power Thrust" or "Super Thrust" features.
  • Ease of Maintenance: Choose a unit with a filter that slides out easily for cleaning.
  • User-Friendly Controls: Look for logically arranged controls, a digital thermostat readout, a built-in timer, and mobile app control.

Installing and Operating Your Room Air Conditioner

  • Installation Tips:
    • Ensure the unit is level for efficient drainage and operation.
    • Avoid placing lamps or televisions near the thermostat to prevent unnecessary running.
  • Thermostat Settings:
    • Set the thermostat as high as comfortably possible to reduce energy use.
    • Do not set the thermostat colder than necessary; it won't cool the room faster and will waste energy.
  • Fan Speed:
    • Use medium or high speed, except on very humid days, when low speed improves comfort and dehumidification.
  • Additional Cooling:
    • Use an interior fan with your window air conditioner to spread cool air without significantly increasing electricity use.

Efficiency Tips

By following these guidelines, you can ensure that your room air conditioner operates efficiently, providing optimal cooling and comfort. For more tips, check out our Energy Saver 101 Infographic on Home Cooling. 

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