Heating and cooling systems
Window and wall air conditioners
A room air conditioner holds a whole cooling system in one cabinet: an indoor coil, a compressor, an outdoor coil and a thin tube that lowers the refrigerant's pressure. In most cases the controls and vent face the room, while the noisy compressor sits outside it. Set in a window or through a wall, it cools the room it serves.
Window, through-the-wall and PTAC units
Room air conditioners come in a few shapes. ENERGY STAR's efficiency requirements for room air conditioners apply to casement window units, through-the-wall units and reverse cycle units, which can also heat. Packaged terminal air conditioners (PTACs), portable units and models with electric resistance heat are not covered by that ENERGY STAR program. Some certified window models use a U-shaped or saddle design that straddles the sill, so you can still open and close the window.
How the compressor runs makes a difference. In a conventional room air conditioner, the compressor works like an on/off switch. Units with variable speed compressors are much more efficient, because they vary the compressor's speed to hold the temperature steady. Chicago does not require landlords to provide air conditioning in all apartments. The renters page explains what your building must provide.
Choosing the right size
Bigger is not better with a room air conditioner. An oversized unit costs more to buy, wastes energy and does not cool any better. A unit that is too large cools the room before it has a chance to remove the humidity. Oversizing also brings poor humidity removal because of too much on-off cycling.
A few room details change the size you need. If the room is heavily shaded, reduce capacity by 10 percent, and if it is very sunny, increase it by 10 percent. If the unit is used in a kitchen, increase capacity by 4,000 BTUs. Measure the room before you shop.
Installation, sealing and drainage
How a unit is fitted matters as much as which one you buy. An improperly installed room air conditioner leaks as much air as a 6-square-inch hole, raising energy costs and making your home less comfortable. ENERGY STAR certified units come with better materials and clearer instructions for sealing and insulating around the unit. Make sure the unit is level so its drainage system works.
Chicago winters add one more step. At the end of the cooling season, remove the unit if you can to limit heat loss, or use a cover of the right size over winter.
Outlets, circuits and cords
A room air conditioner draws a lot of power for a plug-in appliance. Air conditioning equipment is among the seasonal appliances that can strain a home's wiring and cause a fire. Limit the use of extension cords, especially ones used to power room air conditioners. Dimming lights, frequent breaker trips or blown fuses are telltale signs of electrical problems.
Wiring work is for a licensed electrician. Electrical safety groups recommend a qualified, licensed electrician for any electrical work in your home, including installing and servicing cooling equipment. Have electric-powered equipment inspected and maintained regularly for safety.
U.S. Consumer Product Safety Commission · Electrical Safety Foundation International
Filters and cleaning
A room unit's filter is the part you can look after yourself. ENERGY STAR certified room units give a visual reminder when the filter needs to be checked, cleaned or replaced. Clean or replace filters monthly during the seasons of heavy use, which lowers bills and helps the equipment last. Some certified units also have an energy saver mode that limits the fan when the compressor turns off. For anything beyond the filter, follow the maker's instructions.
Replacing and disposing of an old unit
Old window units need care at the end of their lives. Many older units held CFC or HCFC refrigerants, in the cooling system and in the insulation foam. Older appliances may also hold mercury, contaminated oils and PCBs, which harm people and the environment. The Clean Air Act requires that refrigerant be taken out of appliances before final disposal.
There are easier ways than the curb. Units left at the curb might end up in a landfill or be disposed of unsafely. Check first with your electric utility for a rebate or appliance turn-in program, and confirm your unit meets its rules. Some retailers pick up the old unit when they deliver a new one, or let you drop it off free of charge. When you replace it, look for a variable speed compressor for better efficiency.
Related pages
- Ductless mini-splits
Ductless cooling and heating for homes and rooms without ducts
- Condos, landlords and renters
Who looks after the shared boiler, the unit's furnace and a renter's heat
- Chicago's heat and cooling rules
The Heat Ordinance, cooling rules, reporting and tenants' remedies
- Sizing heating and cooling
Why size matters, load calculations and short cycling
- Central air conditioning
The parts of a split system, what is normal and the signs of trouble
Sources
- U.S. Department of Energy. DOE Room Air Conditioner Rulemaking—Engineering Analysis.
- ENERGY STAR. Room Air Conditioners.
- U.S. Department of Energy. Purchasing Energy-Efficient Room Air Conditioners.
- U.S. Department of Energy. energy.gov: Purchasing Energy-Efficient Room Air Conditioners.
- Chicago Sun-Times. Is your Chicago apartment too hot? Here's what to do.
- U.S. Consumer Product Safety Commission. CPSC, ESFI Warn Consumers About Electrical Hazards in the Home.
- Electrical Safety Foundation International. Air Conditioner and Fan Safety.
- ENERGY STAR. ENERGY STAR Room Air Conditioners Key Product Criteria.
- U.S. Department of Energy. Consumer Guide to Home Heating and Cooling.
- U.S. EPA. EPA Appliance Disposal.