Central Air AC temperature? Standard?

[MP]

*** post for FREE via your newsreader at post.newsfeed.com ***

Hi,

I was wondering if a normal AC unit outside the home has a standard rating of air temperature that it is pushing inside the home through the vents. My AC is on for long periods of time and I'm wondering if this is the problem.

My house is old so it's not as well leakproof as a new one, but the AC unit is new (several years old) and I was wondering if there is something I need to do or check.

Thanks in advance.

-----= Posted via Newsfeed.Com, Uncensored Usenet News =-----

- The #1 Newsgroup Service in the World!

-----== 100,000 Groups! - 19 Servers! - Unlimited Download! =-----

[Joseph Meehan]

Ideally the A/C will run almost continuously on those hot humid days. It will also run that way when you first start it up if the house has been opened up to the outside air long enough to let in a lot of moisture from outside (as can happen with that nice cool, but moist night air.)

I will leave the direct answer to your question to someone who has that information, but as I recall it is a matter of temperature difference, not a specific temperature.

[Doug Kanter]

Why is this ideal?

[Ken]

There is of course no direct connection between the outside air flow and the inside air flow. The outside air is used to remove heat from the freon/puron that has returned from the evaporator coil so that it can cool the inside air.

There will no doubt be posts from others knowing much more about A/C than I, but the temperature in your house is due to many factors. The temperature outside, the proper charge in your unit, the cleanliness of the coils (both inside and outside), and other factors. What I would do is try to determine how much lower the temperature of the air is just before leaving the cooling duct versus the temperature of the air entering the cold air return. A temperature about 20 degrees F lower generally indicates the system is operating well.

Again, there are many more factors. This is just a good place to start.

[Edwin Pawlowski]

The longer it runs, the more humidity removal. Oversized units run for a short time, cool the air, but leave most of hte moisture making it feel very damp. I know of a printing plant that on certain day would run the heat along with the AC to force lower humidity.

[JimL]

What you say is true.

However, my brother-in-law had a new unit installed on his home and demanded that it lower the summer time temperature down to below 68 and do it fast. This is in Southeast Texas with outside air temp of

95 degrees plus.

So I guess what I'm implying is "Different Strokes for Different Folks".

[Joseph Meehan]

In many parts of Texas the humidity is not an big issue. In many other parts of the world it is. I wonder why anyone would want to be able to lower the temp to 68º fast on a hot day. OK 95º may not be hot there.

[Stormin Mormon]

Since it's running a long time, it sounds as though it's not cooling your house adequately.

time to call a HVAC guy. Who should check the freon pressures, clean the coils (at least the outside one) check the air flow, and see if the system is running well.

[Dr. Hardcrab]

Ed makes a good point:

I have seen many a homeowner that says stuff like:

"I have a 2 ton unit and on really hot days (90 degrees plus) the A/C seems to run all the time! So when we installed a new unit, we insisted on them putting a 3 ton in!"

Sure! It will "cool" the house, but then you get cold and clammy because it doesn't run long enough to get the humidity out of the house.

Some people think I am crazy because I keep my thermostat at 76 degrees. ("Why not 72??!!) All I know is, when i come home, the house feels comfortable.

I think a great philosopher once said: "It's not the heat. It's the humidity!" (or was that "stupidity")

;-]

Can't go wrong with having a proper manual "J" done......

[TP]

You may want to clean the inside coil also. Check the air filter first. I?ve seen filters very dirty and block the air flow. The chilled air couldn?t get into the house. My unit runs more when the outside humidity is high. If my inside temp is set below 72, the unit will run a lot to keep it there. Is your outside unit in direct sun all day? May need some shade?.

[RP]

How can running for long periods be a problem? Hey, my car went farther down the interstate the other day than it normally does, maybe I should take it in for a checkup :)

Which is it?

Is it keeping the house cool? Maybe it's just hot outside, eh?

If you seriously suspect a problem then have it checked out; we can't diagnose it from here, and you haven't given enough information to even fashion a WAG.

hvacrmedic

[Doug Kanter]

Right - I know it has to run long enough to remove the humidity, but running constantly seems odd. I think this is why it takes more than just the square footage of the house to know what size unit to install.

[Doug Kanter]

That's the name of the survey I can never remember, I guess because I don't buy AC units every year (knock on wood...). I keep my house around 76-78, too. The thing runs for a hour (or less if it's cloudy). Then, it's off for

2, on for another hour. If it ran constantly, I'd be looking for a 2nd job to cover the bills.

[JimL]

ALL OF SOUTHEAST TEXAS IS HUMID!!!

Why would you wonder why someone would want to lower the temp to 68 degree fast? I think on a hot day, everyone wants the temp lowered fast and he happens to prefer 68 degrees. I see nothing wrong with someone having a preference other than yours. Why do you begrudge someone's preference that is different than yours? Do you have issues with those who see things different than you?

I suggest you read the book, "I'm OK, you're OK".

Have a nice day.

[Stephen King]

**** Post for FREE via your newsreader at post.usenet.com ****

JimL wrote in news: [e-mail]:

My dad always set the A/C at 70°. Sometimes we had to go outside and warm up. LOL.

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= *** Usenet.com - The #1 Usenet Newsgroup Service on The Planet! ***

Download - 19 Seperate Servers - 90,000 groups - Uncensored

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

[Joseph Meehan]

That is why I did not say humidity is not a problem in all of Texas only in "many parts."

No, it does not bother me if someone wants 68º. However I might wonder if he is saying that because of insufficient knowledge of what the consequences may be. Getting too large a number may result in poor comfort. I can remember when central A/C first came in and many units were greatly oversized. I also remember so many people, including my parents, who visited those homes and were not comfortable because it was not controlling the humidity. It was many years later when I was on my own that I first had central A/C.

Yes ignorance does bother me. If someone wants 68º and knows what it will mean, then fine. But I would not want any of my friends putting in a overly large unit because they don't know better.

[Edwin Pawlowski]

Not necessarily. AC's are rated in Btu per hour. It takes a certain amount of Btu (heat energy) removal to cool your house 10 degrees.

Let's assume you need to remove 24,000 Btu per hour to maintain that temperature drop. What is the energy consumption difference in running a

24,000 Btu unit for one hour versus running a 48,000 Btu for a half hour? Not much, really. Yes, there will be some difference, but it will not be half/double by comparison.

Yes, there will be some difference because the blower is running longer, but that is a small portion of the cost compared to running the compressor. There will also be less temperature swings if it runs longer. The most efficient and most comfortable setup is the one properly sized for your home and climate.

[MP]

*** post for FREE via your newsreader at post.newsfeed.com ***

Thanks for all your replies. I will be cleaning the filter today and also cleaning the coils on the unit outside. The unit itself is not in the sun all day, about half a day, the first half of the day.

Cheers

-----= Posted via Newsfeed.Com, Uncensored Usenet News =-----

- The #1 Newsgroup Service in the World!

-----== 100,000 Groups! - 19 Servers! - Unlimited Download! =-----

[HvacTech2]

Hi MP, hope you are having a nice day

On 09-Jun-05 At About 03:14:54, MP wrote to All Subject: Central Air AC temperature? Standard?

M> From: "MP"

M> *** post for FREE via your newsreader at post.newsfeed.com ***

M> Hi,

M> I was wondering if a normal AC unit outside the home has a standard M> rating of air temperature that it is pushing inside the home through M> the vents. My AC is on for long periods of time and I'm wondering M> if this is the problem.

M> My house is old so it's not as well leakproof as a new one, but the M> AC unit is new (several years old) and I was wondering if there is M> something I need to do or check.

Although this is not the only check that is made in a maintenance routine the difference between the return and supply should be abut 18 to 21 degrees. the best thing to do is get a maintenance done on your system twice a year to keep it running efficiently. once for heat and once for cooling.

-=> HvacTech2