Pictures for different types of air conditioners can be found on the websites of major department stores, such as Sears, Lowes, Home Depot and Croma. Pictures can also be found in appliance buying guides on websites such as Consumer Reports.
Air conditioners can be divided into single stage and multistage. Single stage heating and air conditioning are preferred both in colder and more humid climates because they are designed to provide optimum comfort in such climates. The downside is such air conditioners do not usually have variable operation parameters, meaning that they are run at full capacity most of the time, wasting energy in the process.
Multistage air conditioning is more suitable for average climates, varying the number of stages running depending on the cooling or heating requirements. Such units save energy and money, even though they may cost more to set up initially.
Further control over heating and cooling can be achieved using zoning, where the HVAC system selectively cools or heats different regions of the home to different temperatures by using zone dampers or valves in the ducts. Blocking or constricting the airflow to some sections while allowing it to flow unimpeded in others allows for variable temperature and humidity control.
Humidity can also be controlled using humidifiers and dehumidifiers, which raise or lower the humidity to acceptable levels in exceptionally dry or humid climates.