Air Conditioning - I may be looking into replacing my central a/c. Need recommendations please.

My question is, "which central air systems would you guys recommend that won't break the bank?" I do want something that has a decent warranty too.

Here's the story:
My a/c hasn't been cooling like it should. I got my usual a/c guy out here, and he told me it looks like my compressor is going south. He tells me the high side is a little low, in turn the low side isn't as low as it should be. Signs of the compressor is going out. I have a Trane 12seer 2 1/2 ton system for a two story 2100sqft home in South Texas. He tells me that I should have a 4ton unit for my size home. 1ton for every 500sqft he says.

I bought my house six years ago this month. My compressor just might be under warranty. I'm gonna look into it tomorrow. If it is I'll just replace that part. If not, then I'll have to get a new system. I do want something that's going to efficiently cool this house. Plus there is that tax credit up to $1500 on new a/c systems on existing homes that I can take advantage of.

Time out.

Did he only take pressure readings? Did he measure the temperature of the freon pipes outside as part of his diagnosis? Did he measure the static pressures in the ductwork? Quoting tons/sq.ft. is improper- it doesn't apportion the heat/cool loads throughout the house. Room by room calculation is the only way to get it right. Has your unit cooled adequately in the past? You might want to do your own load calculations.

HVAC Software, HVAC-Calc for Heat Loss, Heat Load Calculations (http://www.hvaccomputer.com/)

$49 well spent. You want a COMFORT SYSTEM not just EQUPMENT. Tying new equipment to inadequate ducting wastes your money. If you bought your home NEW 6 years ago, the compressor might be in warranty. Some warranties are for 10 years. You may want to consider finding a different moron, er... technician.

I agree a load calc is the only way to size equipment. If you do replace your system, the installing contractor is more important then the equipment. Focus on hiring a good contractor not a brand.

Time out.

Did he only take pressure readings?
You may want to consider finding a different moron, er... technician.

According to my wife all he did was take the pressure readings. None of that other stuff. I think he just want to sell us a whole new system so he can make money. He quoted me $700 in labor just to change out the compressor. So did this other guy I called. I guess that's the going rate to swap out a compressor. I wish I could pick up that compressor, I'd do it my damn self. I don't have an a/c license though.

You might want to get a second opinion before condeming the compressor.

Before you spend any big money, Have you done yearly maintenance, or every two years...Have you ever cleaned you inside coil (at least check to see if they are clean) and out side condensing unit (those small fins)...in house filter clean ? etc. usually the A/C unit (including compressor) should run for more than 6 years if you take good care of it. So I suggest you get another tech's opinion first before you spend that tons of money...It may just be something minor... One other point about A/C size, if 2.5 ton has been enough for the last 6 years, then there is no need to go over 2.5, the new unit (if you have to get one) will have much better efficiency anyway..