Air conditioners, both window units and installed, contain Freon, a substance which can contaminate the groudwater and is poisonous to humans and pets.
It is illegal to place air conditioners in the garbage. It is illegal to cut a freon line and evacuate this substance onto the ground.
Some businesses are licensed to properly dispose of appliances containoing freon and other hazardous substances and recycling parts or by collecting appliances for a recycler.
Most garbage haulers offer pickup of properly tagged (free of freon) appliances for a fee. Contact your local garbage hauler for more information. When purchasing a new appliance ask the retailer if they will take the old one and dispose of it properly when they deliver the new one.
You may safely dispose of air conditioners at Keep Northern Illinois Beautiful’s annual metals and electronics Drives for a $10 decanting fee.