As you shove an air conditioner into your window to ward off the heat, you may wonder why such a small appliance is so incredibly heavy.
If you thought it was some conspiracy to break your back and your window sill at the same time, you'd be wrong. Air conditioning units are laden down with copper which weighs a whopping 8900kg for each cubic metre of metal. This copper is hiding in the evaporator and the condenser coils which remove heat from the air and replace it with cool air. Even the compressor has smidgin of copper. Almost 60 per cent of the weight of the cooling unit comes from these copper components.
Despite its weight, copper is the #1 choice among manufacturers as it is abundant, relatively inexpensive and an excellent conductor of heat which makes it perfect to keep you cool as a cucumber on even the hottest of days. [Slate]