Do I need a new A/C?


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Old 06-13-09, 03:13 PM
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Do I need a new A/C?

Hi-

I live in the south, deep south in Louisiana (I can almost see the Gulf of Mexico from my house). that means that I live in a tropical climate. Today is a balmy 98 degrees.

I think I might need a new A/C. My son-in-law thinks I need more insulation. Maybe you can resolve the difference of opinion.

House is 25 years old. I do not know the age of the A/C, I would imagine it to be 10-15 years old. Who knows, it could be original. The house faces west, and the front of the house (open floor plan - one big room in the front, plus one bedroom). The back of the house (master B/R, guest B/R) gets a lot of shade, and never any serious sun. The front of the house gets full afternoon sun.

In the spring and fall, the A/C works fine. In the summer, it works its butt off. The thermostat is in the big room, and is set at 77 degrees. Most of the afternoon and on into the night, the front room stays about 80-85 degrees. The rest of the house (except the b/r on the front of the house) is comfortable and stays about 77 degrees. When we go to bed at night, the MBR is fine, but the A/C is still running, and it takes until 1 or 2 in the morning to cool down to 77.

Any suggestions on how to get that front room cooler?

Thanks,
carl
 
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Old 06-13-09, 03:33 PM
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Carl,

You would do well to get a qualified a/c service person to first make sure your unit is working properly.
If it is working to capacity then the next thing to do would be to get an a/c firm to do a load calculation on your house to see what size a/c unit would be right.

Here is a site that offers a diy way of doing your own a/c calculation for a reasonable price.
 
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Old 06-13-09, 05:33 PM
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Though GregH's advice is sound, I would put my money into saying your unit is doing it's job to the best it can, this from reading your post that during the spring and fall all is good.

I would also suggest that we have here a balancing problem. A load calculation, as GregH suggests as well, will reveal the cooling needs (Btuh) and the amounts of air (the CFMs) each room needs, but the work should not end here, you have to follow thru by having someone going from register to register with a flowhood measuring the CFMs and making adjustments on the balancing dampers as needed.

If that big room where the thermostat is located has a big size window as well, I'd advice you install a canopy outside of the window. Windows are killers when it comes to letting radiant heat in.

Your in-law's advice on the insulation is well meaning, and he could be right on the money, but only by looking inside the exterior walls you'd know for sure, and ripping off walls to add insulation is a major undertaking...and expen$$$ive as well.
 
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Old 06-13-09, 08:51 PM
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Originally Posted by pflor
Your in-law's advice on the insulation is well meaning, and he could be right on the money, but only by looking inside the exterior walls you'd know for sure, and ripping off walls to add insulation is a major undertaking...and expen$$$ive as well.
He was only talking about adding insulation to the attic.

There is not a large window, but two smaller ones. we have light dampening shades on them, I think maybe we need to get some blackout shades on them, but I hate to lose the light.
 
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Old 06-14-09, 05:15 AM
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How much insulation do you currently have on that attic? Is it fiber-glass (the one that comes in rolls)?

Every little bit helps. I presume you have a one-story home, in which case (and depending how much insulattion you currently have in that attic), an extra layer would be must beneficial.

I have a 2-story home and not long ago I added 4 more inches (of unfaced fiber-glass) to the original 6 (faced) that the builder put in when the house was built. You can tell the difference...and by the ceilings not getting that warm anymore, the radiant heat reflected from the ceiling has diminished, so that it feels comfortable even with the thermostat at higher setpoints. give it a try.

And here is a weblink that I'm sure you'll find useful. Amongst other things, I'll tell you how much insulation you should have in the part of the country where you live, to make your home more efficient.
Energy Savers: Adding Insulation to an Existing Home
 
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Old 06-18-09, 06:17 AM
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Here's what we did

Got an A/C repairman over to look at the unit. The unit is 15 years old, but it's a Rheem and the tech said it was an excellent unit and should last several more years. He cleaned the outside unit, added some freon, and we were good to go. It dropped the temperature inside 8 degrees in about 3 hours. It was over 100 yesterday, and it never got above 80 inside.
 
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Old 06-18-09, 06:31 AM
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How much refrigerant did he add?

Did he locate and repair a leak?
 
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Old 06-20-09, 06:55 PM
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Originally Posted by dun11
How much refrigerant did he add?

Did he locate and repair a leak?
Haven't got a clue, but it wasn't a lot.


No, he didn't.
 
 

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