Grill or grille air registers are typically made of wood or metal. Many of these have wide, square holes rather than linear slats or slots in order to distribute a larger air flow. A wooden air register is the ideal choice for a duct located on a wood floor. Stainless steel or aluminum air registers may blend better on gray stone or slate floors. The different materials, colors and finishes of air grilles and registers allow home designers to create cool or warm looks to suit specific decors.

The best methods for recycling refrigerant require an explanation of what refrigerant is and its role in the cooling cycle of refrigerators, freezers, air conditioners and other appliances. Refrigerants are compounds used in cooling that are boiled from liquid to gas then condensed back to liquid. In the 1980s, many of those compounds were discovered to be major contributors to ozone depletion. 

Since the Montreal Protocol (1987), countries all over the world are agreeing to phase out toxic refrigerants and other hydrochlorofluorocarbons (HCFCs) with natural, environmentally friendly compounds.

Refrigerant's power to deplete the ozone and contribute to global warming decreases when proper methods for recycling are followed. One of the best methods for recycling refrigerant starts with installation. HVAC technicians must ensure that home systems that use refrigerant are installed properly. This prevents HCFCs and chlorofluorocarbons (CFCs) from leaking into the atmosphere in the first place.

Portable air conditioning units are similar to window units, but they can be moved around from room to room. They are generally used to cool small spaces such as a small bedroom or office. Portable air conditioning units are often used to supplement a central air conditioning system, in situations where a little extra cooling may be needed. This might include a computer server room, where the computers give off a lot of heat but must be kept fairly cool to operate properly. Portable air conditioning units also work well in small meeting rooms crowded with people, or helping to cool that one bedroom in your house that's always too warm even when the rest of the house is comfortable.

A portable air conditioning unit works in much the same way as a standard window unit. It has a compressor and uses a gas, normally freon, to remove the heat from the air. This hot air must be vented through an exhaust hose, which is routed out a window or into an adjoining space such as the attic, or into the space between the walls. Portable air conditioning units also collect condensation from the air that is cooled, so most units have a water reservoir that must be emptied from time to time.

A mechanical refrigeration system cools by circulating a fluid through a sealed circuit of pipes or tubing. The fluid absorbs heat in the space to be cooled and carries it away to where it is less objectionable. The entire cycle relies on just a few components and laws of physics to reduce the temperature of an area.

The mechanical aspect of the cycle starts with a compressor, a combination electric motor and pump. In the compressor, a low pressure, gaseous refrigerant is squeezed down to a greatly reduced volume. This compression raises the refrigerant’s temperature and pressure and pushes it into the next component, the condenser. The condenser is merely a coil of tubing over which air can flow. In the condenser, the high pressure/high temperature gas releases its heat and becomes a liquid.