What is wrong when the Central Air Unit is working and there is enough coolant but it is still not cooling ?

Question

Our home air has been checked by a heating/cooling person, he added some coolant, however, it is 103 outside and 82 in side a split floyer on the upper floor all vents down stairs are closed and the thermostat is set for 72, it is running constant and air is blowing cold, electric bills are high!

Answer 1

Probably you need better insulation. Also, you might check the efficiency rating on your a/c unit, and consider replacing it with a more efficient model.

I have been having the same problem, so I added a small window unit. It has been keeping the apartment 30 degrees cooler, and lowered my power bills. Look for the BTUs of the a/c as well as the efficiency rating.

Answer 2

I have to say this. All of you guys that say the unit can only keep a house 20 degrees cooler than the outside are completely wrong!!!!! I don't know where you get your information but please look for a new source. All of the A/C technicians that say this don't understand how to do a load calculation.

The people that say insulation and good attic ventilation are correct.

What is going on is this. When a load calculation is done it is based on a specific design temperature which varies from region.
In the region I am located, the design temp is 97 1/2 degrees.
Basically that means on a 97 1/2 degree day the heat entering my house is the same as what the airconditioner can take out.
This will only maintaine the inside temperature. On cooler days or at night the amount of heat entering your house is less than what the unit can remove which allows for the temperature to lower.

Most units are designed to operate efficiently at 100 degrees outside. So at 103 degrees your unit is not doing as much cooling as it could do on 100 degrees or lower.

Since the load calculation was done below a 103 degree day, you have more heat entering the house than the air conditonioner can take out.

If the house is about 10 years or older, the insulation has settled, small cracks and air openings have appeared making the house insulation rating less than when the calculation was done and the house is less "tight". So if all of this has happened in a house designed at 97 1/2 degrees actually lowers the temp to maybe 94 degrees. So now at 94 degrees the house can only maintaine and not cool.

The quickest and cheapest thing may be just to add a window unit to help make up the difference (as mentioned)
For long term you will need to consider adding insulation, attic exhaust fans, weather stripping, new energy efficient windows and many other things to consider. Your local utilities should have recomendations and other programs that may assist you.

As long as your unit can take out more heat than what is entering the house, you will be able to lower the temperature. The warmer the day, the slower it may lower the temperature.

Answer 3

If the air a coming out of the air conditioner is approximately 20 degrees colder than the air entering the air conditioner the system is probably working OK,and you have other problems too numerous to address here. A few things to consider: did it always fail to cool the house?could be too small a unit; do you have adequate insulation in attic?; Is duct work broken apart? I once found a cat living inside a detached air duct. Hope this helps.Good luck. I almost overlooked a very important point. you mentioned some of the vents are closed,this may not be good,because air conditioners are designed to require a certain amount of air to pass through the cooling coil,if not coil can freeze.

Answer 4

First, the best you can get is a 20 degree difference from outside ambient air temperature to indoor temperature, Unless you want to run a refrigerator unit and store side of beef in your living room.
The best advice I can give you here is not to close any vents anywhere in the house. This causes your unit to work harder.
Use ceiling fans or box fans to circulate the air throughout the house. Make sure filters are clean. Check your weatherstripping.
If your house has a large open space such as a vaulted ceiling, with these type of designs it is rather hard to keep these areas cool as heat rises and traps the heat in a layer that is hard to break down. If you have a second story, ceiling fans help with this.

Answer 5

Sounds like your home is lacking in insulation. Also if you have one unit for the whole home it has to work twice as hard. Not to mention an AC system typically cannot cool more than 20 degrees than the outside temp. Check to see if the coils outside are clean & not being blocked by shrubs. The fan needs good airflow. If the coils are always in full sun you may want to erect a canopy to shade it without blocking its air flow.In the shade it would be able to exhaust the heat better.

Answer 6

The job of central air is to keep the house 20 degrees cooler than the outside temp. So it if is 103 outside, you don't have much of a chance of getting the house to 72 until the sun goes down.

Answer 7

If your unit has been working OK in the past years your problem could be a clogged evaporator coil. This is very likely if you have had remodeling work done lately or have been running your unit without a filter. To find out you will need to open the plenum on the air handler and look into the inside surface of the coils. If cleaning is needed a wire brush will work to loosen and flush out with a spray mist of water. Be sure the condensate drain is open.(Not clogged)

Answer 8

103 outside and 82 inside. that system is getting the job done, its not going to lower the room temp any more than twenty degrees.

Answer 9

You could have to much coolant that is just as bad as not enough some HVAC guys add more just so it looks like they did something. .......your best bet is install an attic fan that pulls all the heat that is just sitting in your attic. it will cost you a couple hundred bucks but pull the temp down fast and save you boatloads on your electric bill. I did it for my aunt 20 years ago and she still thanks me.

Answer 10

I agree with the others that your home may very well be underinsulated. One really inexpensive thing you can check and/or remedy is the seals around your doors. Weatherstripping costs next to nothing but makes a HUGE difference!! If in doubt, replace or install weatherstripping.