Most Davison homes have a central air conditioning split system for those days our near-perfect climate gets a little too warm.They are called split systems because the condensing unit is installed outside and the gas furnace or air handler, with the evaporator coil, is installed inside.This Davison HVAC guide looks at how central air conditioning works, why sizing it correctly is important and factors affecting price.


How Your Home Air Conditioning Works

The condensing unit contains a condensing coil, compressor, fan and other supporting parts.  The furnace or air handler contains the evaporator coil or A-coil which refers to its shape. Two copper refrigerant lines connect the 2 coils.  The system is charged with refrigerant, a substance that has the ability to absorb and shed heat very quickly. When the thermostat calls for cool air, the compressor begins to cycle refrigerant through the system.  In the evaporator coil, the liquid refrigerant evaporates, turning to a gas and collecting heat in the process.  Heat is drawn out of the air surrounding the coil, which has the effect of cooling the air.  The cool air is pushed into the supply ducts to cool rooms in the house while warm air is pulled into the system through the return ducts.

The hot gas refrigerant travels outside through the second copper line where it enters the condensing coil.  There, it sheds its heat while condensing back into a liquid.  The condensing coil has fins on it like a radiator that assist with the transfer of heat.  The fan disperses the heat as it radiates out.  This cycle continues until the house is sufficiently cooled.  One additional benefit of this process is that it also removes humidity from your house.  As the indoor coil cools, water condenses on its A-frame sides, runs into a pain, and enters a drain.  Air conditioning can remove as much water from your home as a small dehumidifier.

Davison AC Split System Sizing Issues

Central air conditioning condenser units are made with different capacities or sizes.  They range from 1.5 ton to 5.0 ton, with a ton being a measurement of cooling capacity.  If the system is too small, it won’t adequately cool your home on very hot days.  If it is too large, it will waste energy and also cool the house and shuts down so fast it doesn’t remove as much humidity.  The best way to ensure the proper size is to have an air conditioning contractor do a Manual J load calculation.  It takes into account your home’s size, our local climate, and other factors related to the construction of your home such as windows, insulation, etc.  Some larger homes require more than one system to meet the AC demands.

Cost Factors in a Central AC System

Several factors determine how much an air conditioner split system will cost.

  • Capacity: Larger units will generally cost more than smaller units.
  • Efficiency: Air conditioning uses electricity, and like cars with gas mileage, some use it more efficiently.  This efficiency is called SEER, or seasonal energy efficiency rating.  The lowest SEER you will find is 13 SEER.  The highest is in the mid-20s.  The higher the SEER, the more efficient it is and the more it will cost.
  • Features: Some air conditioners have 2-stage compressors that run on low most of the time, and on high only when necessary.  These are quieter, produce more balanced cooling and do a better job dehumidifying the house.  Other features include better system diagnostics or communicating technology that coordinates the system for maximum performance.  Units with more features will cost more than standard units.
  • Installation Issues: Time consuming installations or those that require extra material are more costly than easy installation.


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