Central Air Struggling

[Tom The Great]

IMHO:

There are other factors with the lenth of operation of your AC unit.

1. How well is your house insulated (your walls)?

1. How tight is your house against drafts?

2. Is your AC Unit in direct Sun?

1. What is "Checked" by your happy company?

2. Have you checked for any blockage around the ouside unit?

1. Is my air filter dirty.

These are just some questions I would ask myself, when trying to determine the health of an ac unit.

Personally, I purchased a couple dial indicating temperature probes, and inserted them into the return, and supply of my furnace/AC coil. I check from time to time for the differencial temp. If you have a differencial temp, to tell us, we might have better insite. Your AC might be working very hard, and have an undersized blower unit to cool your home.

later,

tom @

[JoeSpareBedroom]

#1: Wall insulation unknown. Built in 1956, upstate NY, so probably some insulation, but not much. All non-destructive inspection methods known to man have been attempted, and failed. But, I'll be doing a couple of plaster-shattering projects soon, and will have a real answer. And, new siding comes next year, along with the customary outside insulation.

#2: Tight.

#3: AC unit's in sun only for the first 2 hours in the morning. Total shade after 9:00 AM or so.

#4: "Checked" in this case meant outside unit cleaned, refrigerant level checked & adjusted (needed very little).

#5: No blockage outside. Very easy to keep clear.

#6: Air filter is clean. Installed badly by previous contractor (along with a number of other things). It's the accordion type, and it binds badly as it goes into the duct, so checking it is not as easy as with a flat filter. I may have the filter system changed.

[Thomas Kendrick]

At the age of this unit, it's probably time to clean the evaporator coils. I had a similar situation here in north Texas. A 17-year-old

2-ton unit on the west side of the house, SEER 10. Today it was replaced with a 2.5-ton unit, SEER 13. The old evap coil was 1/3 blocked with wet dust. The lower 2/3 I had been able to clean with a can of foaming coil cleaner. It looked clean from the side that I could access but the far side told a different story.

Coil cleaning is not an annual checkup item and typically runs about $200+ when done professionally, but it would make a world of difference if the unit was otherwise sound.

[Tom The Great]

Well....

Since your replies seem to imply the unit is operating as designed (i forgot to ask about evap coil being check), maybe the unit is undersized for the house.

Sorry, it sounds like you need a technician on site.

tom

[JoeSpareBedroom]

Yeah...I get the same feeling. Luckily, the company I use will send out the owner to survey the house for a possible replacement, but without a huge pain in the ass sales pitch. Just "Here's the right unit, call when you're ready. Doin' any fishin'?" Pleasant people. And, when the furnace needed service last winter, the tech arrived in sloppy, snow covered shoes, removed them, and pulled a dry pair out of his tool bag. WTF? Who does that these days???????????