How cold should my central A/C blow?

[10shotgroup]

I been noticing my central A/ C has Been running longer each day to maintain temp. I chalked it up to blazing hot outside temps and my own paranoia. Well today I put a manual thermometer in the vent closest to the a-coil ( literly 3 feet). 60 degrees is as cold as it got. Is this what it's supposed to be or do I need to call someone?

 

[kcinnick]

Its not really how cold should it blow, its how much colder the air coming out is than the air going in. The rule of thumb from my research is atleast 15 degrees, many units pull it down more.

Its really hot, you are probably requesting your A/C to drop the temp 25 degrees, that is a lot of heat exchange.

 

[CrkdLtr]

Yeah, I have this same fear every summer. Basically your Central Air can only keep your house +/- 20 degrees cooler than the outside temperature. So if it's a 100 degree day, then it's not uncommon that your house is 78 to 80 degrees inside with your A/C running non stop at 74 degrees.

That is, unless, you have larger A/C system than you need for your house then you should be able to keep it as cold as you want.

I've started using a 10,000 BTU window unit in the living room on those days when the Central Air can't keep up. I've also adjusted my thermostat to 76 instead of 74. I find my unit can keep up with 76 degrees (and take not stay running as long) than when it's set at 74.

 

[kcinnick]

My intake is @76 right now, and it is blowing 58.

 

[spanky]

Mine stays 74 during the day and 70 at night.

 

[10shotgroup]

My intake is @76 right now, and it is blowing 58.

Well it seems I'm in range then. This is my first summer in the house so i'm just figuring these things out.

It's not running 24/7 by far. It's set on 76 right now. So I assume the intake would be around that +\- and output at 60. When i crank it down to 72 or 71 at night it runs awhile to bring it down.

I guess it's just my paranoia and not know my new a/ c.

My house is 2200 living and my elec. Bill last month was only $151 so I can't complain too much.

 

[diat150]

should be about 16-20 degrees different from the intake. if that is the case I would look at your insulation and any leaks that may be allowing cool air out and hot humid air in.

 

[kcinnick]

Mine can pull 70 at night, but by mid afternoon its gets about 78 no matter what I have it set on these past couple weeks.

 

[drumz2129]

One thing to make sure to do each year is to clean your outside coil. Ants love to build mounds on them and grass gets stuck in the fins. The more blockage on the coil the less surface area to radiate the heat which lowers the efficiency drastically. Another thing is to make sure to change the air filter monthly and use the cheap disposable ones. The expensive 'HEPA' filters restrict the air flow too much. Another place to check is your duct work and plenum. Feel around them when the unit is running for any stray streams of cold air. If you have a ducted return also check the connections there to see if it is drawing any hot air in from the attic.

 

[sandman7925]

Normal for allot of homes during July and August

 

[jimdana1942]

20 degrees colder than incoming air, however, I check my window units with a thermometer and when 80-85 going in it is 52-55 going out. How many tons is your unit (BTU's)? I do know that a car air conditioner should get in the 40's or you will not be as comfortable as you should.

 

[Yrdawg]

another big help is a meter to test dewpoint temp....this will give you information about infiltration of out side air, shoot for a end run cycle DP temp of hi 50's, lower is good

No more than a 4 deg rise ( dew point ) at start of run cycle

If you can keep you relative humidity in th 50's 78 will feel great and use less run time