Package Air Conditioners

Sometimes the term “Package” unit is confusing, but in this case we are referring to a self contained unit that comes pre – assembled. The differences between this and a window unit or PTAC are substantial. First, a package unit usually can cool and / or heat the entire home or building, and this system is connected to a ducting system, unlike the window unit or PTAC. If the unit also includes gas heating, they are sometimes referred to as a “gas pack.”
Package units sit outside the home on the ground or on the roof. In trying to identify this type of system, you won’t normally see copper tubes coming out of it to the house, but you could see ductwork, or a large boxed in area connecting the unit to the house that the ductwork runs through.

Ductless Split Systems

This type of unit is very popular overseas where many buildings do not have ductwork. They are becoming popular in the US where homes need to be cooled but no ductwork exists, such as in the case of homes heated with boilers.
The system has an outside condensing unit, very similar to a regular split system air conditioner. It also has copper tubing running to an indoor unit. However, the indoor unit(s) (It can have multiple indoor units with one outdoor unit) are not ducted, they simply hang on a wall or mount in the ceiling. These are not put in a window – like the window air conditioner, and they don’t need a huge hole in the wall – like the PTAC unit. They are much quieter than window units, because the noisiest part of the system is outside. Another advantage is the ability to have multiple indoor “blower” units, giving you air conditioning in more than one room.

Split System Air Conditioners

These units are among the most commonly installed systems around. Usually a unit sits outside – this is referred to as a condenser. The condenser has wires and copper tubes that lead inside, usually to the location of the “air handler,” “furnace,” or “heater” (we will call this the “indoor unit”. An air conditioning evaporator coil is located over, under or beside the indoor unit. This unit normally comes in separate pieces and is custom installed in each application. When used in combination with an air handler, furnace or heater, the blower from the indoor unit drives the flow of indoor air through the system. The unit style gets its name “Split System” from the fact that the unit is split into an indoor and outdoor section.
The air conditioning condenser (outdoor portion) will normally be located on the ground beside the house or on the roof. The indoor unit and coil (air handler, furnace or heater) will normally be located in a basement, crawl space, closet or attic and is connected to a duct system that circulates the air through the home.

Some of the possible components of a “Split” system

Air Conditioning Condenser - Air Conditioning Condensers are the outside portion of a “ Split” system air conditioner. The Condenser is typically connected via copper tubing to an Evaporator Coil that is located in the Air Handler or in combination with some type of Furnace. An Air Conditioner uses refrigerant (commonly called Freon), circulated through the system using a compressor. The heat from the home is absorbed into the refrigerant and transferred to the outdoor unit. This is why you can hold your hand over an outdoor unit in the summertime and feel it blowing out hot air.

Heat Pump Condenser - Heat Pump Condensers are the outside portion of a “ Split” system Heat Pump. The Condenser is typically connected via copper tubing to an Evaporator Coil that is located in the Air Handler or in combination with some type of Furnace. Heat Pumps work exactly the same way as an Air Conditioner in the summer, but reverse their operation in the winter. As strange as it seems, even down to about zero degrees Fahrenheit outside, a Heat Pump can capture heat from the outdoor air and transfer it via the refrigerant to the indoor conditioned space.

Evaporator Coil - The Evaporator Coil is the indoor portion of an Air Conditioner or Heat Pump system. The Coil usually is not visible, but is placed somewhere in the air stream of a ducting system, usually very close to the furnace or air handler. The Coil is connected to the outdoor unit via copper tubing and normally you can see where these tubes attach to the inside unit or ductwork.

Air Handlers - An Air Handler is the indoor portion of a “Split System” air conditioner when the air conditioner is not using a furnace as its air moving system. The air handler is simply an electric furnace that includes the air conditioning evaporator coil inside. Air handlers might also be referred to as an electric furnace. An air handler or electric furnace usually can be identified by not having a flue pipe (chimney or exhaust) that is used with a gas or oil furnace. Air Handlers that also provide heat from electric coils normally have a large electric circuit feeding them, anywhere from 30 to 120 amps.

Window or Wall Units

Window Units - As the name implies, if you have a unit that is stuck through a window – it is a window air conditioner. These units are useful as a solution for one room but they can be noisy, inconvenient and of course – block your view out of the window. These units are completely self-contained with a refrigeration system (see How an Air Conditioner Works) and fans to move the air.

Through the Wall Units - If you have ever stayed in a hotel or motel, many of them use a through the wall unit, commonly called a “PTAC”. Similar to a window unit, these systems are convenient for a small area, but sometimes can be noisy. These units are also completely self-contained, just like the window air conditioner.

Evaporative Coolers

Evaporative Coolers are typically referred to as “Swamp Coolers,” a name they gained partly due to the way they cool. Evaporative Coolers use evaporating water to remove heat from the air. These units work best in very dry climates and are most popular in the southwest and desert areas. For an example on how Evaporative Coolers work, try holding your hand six inches from your face and blowing on it. Even though the air in your body is warmer than the air around you, your hand feels cool. This is because the moisture on your skin is evaporating – and when water evaporates it absorbs heat!
Evaporative coolers use evaporation to remove heat from the air, but they do it using water. Water flows over a media that air is pulled through, causing the water to evaporate and heat to be absorbed. These units are very common in the southwest, but require a very dry climate to work effectively.
Swamp coolers are normally located on the roof and can sometimes look like a “split system” outdoor unit, but have a water pipe feeding into them – which the others do not. A Swamp cooler must be drained for winter each year to prevent freezing.