The key components of [a split system](https://homesteadycom/facts-6941747-split-system-html) are the furnace, the condenser, the compressor, the heat pump and the evaporator coil. The heat pump transfers hot air inside your home to the outdoors so your system only circulates cool air throughout your home.
The reverse happens in winter. The metal cabinet that is usually located indoors (in your garage, basement or in a closet unit) contains the furnace, heat pump and the evaporator unit.
The metal cabinet outdoors houses the condenser and the compressor. If your home already has a furnace and you are purchasing a new air conditioning unit or replacing an older unit, a split system is usually the most economical choice for a new installation or an upgrade.
The components of a "packaged" central air conditioning system are the same as those of a split system. The difference is that most of the components for the air conditioning system are all in one location.
In most cases, that location is either on the roof or on a concrete slab outdoors, next to the foundation of the home. Outdoor packaged systems are also commonly installed for smaller commercial businesses.
Since all of the components are "packaged" together, these types of systems usually do not require the use of an indoor furnace, because the system functions independently.
If you are purchasing another air conditioning unit, look for a new, energy efficient model. Your investment will pay off because the typical lifespan of an HVAC unit is 10 to 20 years.
Plus, the more efficient the unit -- the more you lower your utility bills. Units manufactured after 2006 use up to 50 percent less energy than air conditioning units manufactured before 2006.
Air conditioning units are rated for their efficiency by the SEER system (Seasonal Energy Efficiency Ratio). SEER measures the relative amount of energy required to generate a specific cooling output.
Units manufactured after 2006 must have a minimum SEER rating of 13. Look for the Energy Star label on models to be sure about the SEER rating.
Units with an Energy Star will have a minimum SEER efficiency rating of 14.
Things to Avoid
Try not to purchase an air conditioning unit manufactured before 2006. It will not provide the maximum efficiencies and you will not experience the level of savings on energy bills that you can achieve with newer models.
Also, avoid systems that do not have the Energy Star label, as they will be the least efficient. The average air conditioning unit in a home uses more than 2,000 kilowatt-hours of electricity per year.
The environmental impact is that the power plant where the electricity is generated will emit 3,500 lbs. of carbon dioxide and 31 lbs.
of sulfur dioxide, according to the US. Department of Energy website, EnergySavers.