Air conditioning is pretty simple, right? You plug in an appliance, and it blows out cool air... right? As it turns out, matters are not quite that simple. Though all air conditioners do cool homes by blowing out cold air, they don't all do so in the same manner. There are actually three different types of air conditioning systems that are used to cool whole home. Which is best for you really depends on your climate, the type of heating system your home has, and your individual preferences. Here's a closer look.
Vapor Compression Coolers
This is the type of air conditioner with which you're probably most familiar. If you hear the term "central air conditioner," this is likely the type being referred to -- though the other types on this list could technically also be considered central since they cool the whole home. Vapor compression coolers have an outdoor unit that sucks in air, plus an indoor unit that consists of a coil filled with refrigerant. The refrigerant inside the coil expands as warm air blows past it, essentially absorbing the heat from the air. The system also removes humidity from the air. As a result, the air it blows out is not only cooler, but also dryer than the air circulating in the home.
Vapor compression coolers are ideal in climates where humidity levels tend to be high in the summer. Since they blow air through ducts, they are easiest to install when you already have ductwork in place from a forced air heating system.
Ductless Heat Pumps
Ductless heat pumps are another type of cooling system. They work in the same manner as a vaporizing cooler, using a coil filled with refrigerant to cool your indoor air while exhausting the heat to the outdoors. Unlike vaporizing coolers, however, these systems do not connect to a series of ducts. Instead, they are mounted on the wall and blow air directly into your room. In most cases, a home will be fitted with several ductless heat pumps, allowing you to control the temperature of various rooms individually.
Ductless heat pumps are reversible, which means that in the winter, you can flip a switch and use the device to heat, rather than cool, your home. It will then gather heat from the outdoor air and transfer it to your home -- rather than the opposite. Ductless heat pumps really only work for heating in moderate climates, but they're a good option for cooling even in the coldest climates if you have a boiler system or baseboard electric heating and therefore no ducts.
Evaporative coolers can also be integrated with a system of ducts, but they work differently than vaporizing coolers. Instead of removing moisture from the air, they actually pass air over moist pads. The air cools due to the evaporation process; this is similar to how sweating cools off your skin. Evaporative coolers are a good choice in areas where the air is dry and hot. They use a lot less energy than vaporizing coolers, especially in very hot climates.
Evaporative coolers are usually placed on the roof rather than beside the home or in the basement. This is because they are so large and can be quite noisy. They do require more maintenance than other types of systems since the cooling pads tend to accumulate grime.
To learn more about these cooling options, talk to an HVAC contractor in your area. If you live in a humid area, a vaporizing cooler or heat pump is likely your best choice, whereas evaporative coolers are effective in dry zones.