Tip & How-To about Heating & Cooling

Lower the cost of your Central Air Conditioning Bill

Dirt is the enemy and your defense is simple and inexpensive.

Central air conditioning units are simple machines which take the warm air from inside your home and put it outside. There are two parts that do the bulk of this 'Heat Transfer", they are the inside coil and the outside coil. A coil that is covered with dirt does not transfer heat very well.

The outside coil is the outer layer of the unit located outdoors. First, shut off the power to the unit. Clear any weeds or decorative plants away from the machine. The machine should have a good 18 to 24" of clear space around it. More is better. If possible, nothing but blue sky should be above the unit. Although there are special detergents used by commercial contractors, I have found that in most residential locations, using a simple garden hose to wash the spaces between the aluminum fins is adequit. If you find that the fins are blocked, you should have a professional coil cleaning. While you are at the unit, take the time to straighten any fins that are bent over. Again, if a large area is bent and you find that you are damaging the fins, call a professional as they have special tools.

The inside coil is not so easy to access. For this reason, a high quality indoor air filter is recommended. Many people use carboard encased fiberglass filters, which cost about $1.00 each. Much better to go with a pleated media filter, even better, one maked high efficiency. Change it whe the surface is covered with a fine, even layer of dirt. Some homes will require monthly changing, most will need it every 3 months and a few will only need it once every 6 months. The Glass Fiber filters only catch the very big pieces, allowing the small particles of dust to flow into you indoor coil. WHile operating in the air conditioning mode, the inside coil is wet. This is because part of the process of removing heat involves removing humidity. WHen the fine dirt mixes with the moisture, a fine mud starts to build. If allowed to continue, the deminished air flow will result in poor performance and will require a professional cleaning that can take as much as 12 to 16 hours and involve extra charges for equipment involved in protecting the environment. In a worst case senerio, low air flow can cause the compressor to fail. Those 'Expensive" filters really are a bargain.

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3 Answers

My A/C blowing air, but it is not cool. It has started freezing up. We just replaced the air filters and since then it is freezing up. We even gently cleaned the a/c coils before replacing the filters. Is there something else we can clean before we call a repairman? We have an Intertherm Central Air Unit.

Hello, sounds like it is either a low charge or lack of airflow, what type of filter are you using? sometimes those filters that claim to be super effecient will actually cut down on your airflow and cause the ac to freeze up.

Jul 15, 2011 | Intertherm Heating & Cooling

6 Answers

Boiler doesn't fire up. 25 years old Amana outdoor boiler model #3612M-A Mfg # P68191-1F,It had leak in pump housing and replaced, replaced igniter ,but no fire, no leak in system ,pump are keep running How to remove air from system and why it doesn't fire up , like to have step by step diagnosis chart Thank you.

How a Central Air Conditioning System Works

  • The typical central air conditioning system is a split system, with an outdoor air conditioning, or "compressor bearing unit" and an indoor coil, which is usually installed on top of the furnace in the home.
  • Using electricity as its power source, the compressor pumps refrigerant through the system to gather heat and moisture from indoors and remove it from the home.
  • Heat and moisture are removed from the home when warm air from inside the home is blown over the cooled indoor coil. The heat in the air transfers to the coil, thereby "cooling" the air.
  • The heat that has transferred to the coil is then "pumped" to the exterior of the home, while the cooled air is pumped back inside, helping to maintain a comfortable indoor temperature.
  • Central air conditioning can also be provided through a package unit or a heat pump.

  • Indoor comfort during warm weather - Central air conditioning helps keep your home cool and reduces humidity levels.
  • Cleaner air - As your central air conditioning system draws air out of various rooms in the house through return air ducts, the air is pulled through an air filter, which removes airborne particles such as dust and lint. Sophisticated filters may remove microscopic pollutants, as well. The filtered air is then routed to air supply ductwork that carries it back to rooms.
  • Quieter operation - Because the compressor bearing unit is located outside the home, the indoor noise level from its operation is much lower than that of a free-standing air conditioning unit.


Sep 10, 2008 | Amana Heating & Cooling

1 Answer

Central air conditioning system is blowing warm air.

many, many. Is the outside unit running? If it is, is the compressor running? Feel the refrigerant lines leaving the unit. Little one should be warm. Big one should be cold, probably sweating.

Jul 08, 2010 | Ruud UAPA042 Air Conditioner

2 Answers

fridge & freezer warm clicking noise is coming from compresser

Clean all the dust and lint accumulation from under the unit, remove the condensation collection pan and clean it, and make sure the bottom fan is running.

I can't emphasize strongly enough how much of an enemy the accumulation of dirt and dust under a refrigerator can be its worst enemy. It can make the refrigerator exhibit symptoms of much more serious problems. Sometimes a good cleaning can have it operating like new with no real 'repairs' whatsoever.

Aug 22, 2009 | Refrigerators

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