How Air Conditioner Units Work
Central AC SEER Ratings, SEER Rating,Cooling System Maintenance,Energy Efficiency, and the Energy Star label
© 2009 by Kelly Smith all rights reserved
The energy efficiency of a central air conditioner is the SEER rating. Maintain it with periodic
condenser and evaporator maintenance, and cleaning and calibrating your analog or digital thermostat.
The home AC system is a crucial component of your homes environmental temperature and humidity
control system. Depending on where you live, it may be operated for half of the year, and in some
areas, much longer.
Proactive homeowners use a professional HVAC service company for some of their air conditioner repairs
and maintenance because you must be licensed to purchase or recover refrigerant.
Find reliable contractors at Angies List - Use promo code LOCAL to save 15%.
But there are many routine maintenance jobs the typical DIY homeowner can handle. To begin with,
its informative to understand just how air conditioner units and the cooling cycle functions. Chalk it up to DIY geekiness.
Types of AC Refrigerants: R-22 and R-410A
Window-mount, portable, and central air conditioners all employ refrigerants to cool, or more
correctly, to remove heat from the air.
R-22 is the most common refrigerant youre likely to
encounter in older units.
Youve heard it referred to by its brand name, Freon.
However, because its thought to contribute to global climate change by depleting the
atmospheres ozone hole, a federal mandate has it being being phased out in the US. Its
still readily available in Mexico.
Freon is being replaced with the refrigerant R-410A. This formulation is also called Puron
(youll notice the clever marketing slight of hand, alluding to the word "pure"), which is its
Carrier/Bryant brand name.
The final date for Freon R-22 production to cease is 2010. Just now, its a great idea not to
your existing AC unit with a Freon-charged one. Environmental pundits tell us that the newer refrigerant
should help stop climate change (previously global warming).
What is SEER Rating?
Seasonal Energy Efficiency Rating. The SEER rating is just about the most important things to consider
when you go looking for a new more energy efficient unit. Your average air conditioner in the early 90s
was rated at 6.
In January 2006 the minimum was increased to 13 (but must be 14 for the Energy Star
label) but some units being produced go as high as 20 or above! Just be ready to pony up the extra money
This begs the question, Is it worth spending the extra money for a more efficient
unit? The answer of course, depends on several things; the primary one being how long you
plan to stay in your home.
Central AC System Anatomy 101
Your central air conditioner system is generally part of a forced-air
home heating system.
The two systems
share a duct system (typically rigid trunk and flex) and a blower They work together to distribute
heated or cooled air to your home at the temperature youve set on your thermostat.
Your condenser is typically located outside your home. Its function is to cool the liquid refrigerant
(Freon or Puron) in your condenser coils.
It next pumps the cooled refrigerant to your evaporator coils. These are located in your home;
usually in the attic, although the basement is used in some locales. Next, the furnace blower circulates
your homes warmer air over the cooler coils.
Two things occur because of this: the first thing is that the evaporator coils function as a
heat exchanger. They do this by absorbing heat from the warm air (unscientifically thought
of as cooling the air).
Secondly, the warmed liquid refrigerant reverts back into a gaseous state. Then it is pumped
back out to your condenser coils and begins the process all over again.
DIY Homeowner Air Conditioner Tasks
Even though an air conditioner contractor is required by building code to install new units and
complete services such as refrigerant recovery, there are a number of springtime maintenance jobs
that you as the homeowner can do.
Tip: Be sure to turn off the AC electrical supply prior to starting any
- First clean your outdoor condenser coils. To do this, use a soft brush with soapy water, and
then rinse it down completely.
- Now straighten the cooling fins located on the sides of your condenser unit. You can use
a fin comb to do this. Make sure youre wearing a pair of work gloves. These fins are very thin
and sharp; theyll cut you deep.
- Check your unit for level in all directions with a four foot level. The refrigerant needs to
flow in and out of the house as engineered and a level unit allows this.
- Finally, lubricate your condenser fan motor using non-detergent machine oil. Youll find
plastic oil port plugs in the motors housing.
- Now, its time to pay some attention to the evaporator coils. Clean your evaporator
coil drip pan, and drop in an anti-fungal tablet. You can find them at Home Depot. Fungus and
other growths will foul your drain line.
- One thing left to do: clean and calibrate your thermostat. A simple analog or 7-day
thermostat tune-up only takes a few minutes and is well worth your
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