In Our climate Air Conditioning is a Must
Air conditioning is a vital need for summer climates. What many people do not realize is that an air conditioning unit can also be used for heating a home in winter. Especially in places that have very hot summers and cool winters, such as Phoenix, AZ, an air conditioning unit is especially appropriate. There are a several options for heating and cooling, and the efficiency of each is determined largely by the climate of the home and surrounding area.
For places that receive extreme cold winter weather, but cool summers, a furnace is ideal. Burning fuel such as natural gas or propane is the best option for extreme cold temperatures because it will not break down or need to be cycled backwards. Swamp coolers or room air conditioners are often adequate in climates that are only moderately above comfortable room temperatures in summer.
For climates that see very hot summers, such as Phoenix, a central air conditioning unit is the most efficient option. Swamp coolers are rather ineffective at high humidity. While Phoenix is ordinarily a very dry heat (due to its location in the Sonoran Desert) the monsoon season can bring enough moisture to render evaporative heating largely ineffective. By contrast, an air conditioning unit will cool a home even as the humidity rises, and indeed, will even de-humidify a home.
Furthermore, an air conditioning unit can be run backwards in winter. Technically, an air conditioning unit must be a heat pump for this to be possible, but the vast majority of air conditioning units in Phoenix are, and work well for this application. For a heat pump to be effective, the air needs to be cold, but not too much below freezing. Also, a heat pump works best as a heater when the winters are fairly dry. Phoenix, with normal humidity in winter hovering around 25% is ideal for this. This is because running a heat pump in reverse moves heat from the outside (even though it may be cold, outside air still has considerable heat energy), and uses it to warm coils on the inside. However, the coils outside the house have to be colder than the surrounding air for this to work. If the outside coils get too cold, ice will form on them (especially in high humidity), this prevents heat transfer, and to remove the ice the system will automatically run backwards, or in the same direction as the air conditioning in summer, to warm the outside coils and melt the ice. This is not a problem if it happens only a few times per night, but excessive backwards cycling is counterproductive to the point of the heater (since it blows cold air into the house when it is happening), and wastes energy.
But for Phoenix, a heat pump will effectively warm a house in winter and cool it in summer, making this single-purpose device ideal.
Scott Baker attended American Trade Instituted with a concentration in air conditioning, heating and refrigeration, and ventilation. He founded Air America Inc in early 2011, and also instructs at EVIT, the East Valley Institute of Technology.