Posted: 7/22/2011 8:04:10 AM EDT
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My current a/c system is about 10 years old, it's a hunk of junk Tempstar that sounds like a full garbage disposal when it turns on and the unit is right behind our bedroom. It seems to work alright if I leave the day time temperature within 2° or so of the temperature I want it to be at when I get home from work. I had the t-stat set at 79° or 78°, kicking down to 75° around 4:30. When I got home at 6pm it was still running and only at 77° or so and would not turn off until 8pm. The high pressure line was very hot to the touch, my a/c guy said it should just be warm.
I have since changed it to only go up to 77° during the day and it's at 75° when I get home now, sometimes even not running due to rainy day or randomness. I cleaned the outside coil by taking off the cover and fan but it wasn't very dirty. I did not use an acidic cleaner to remove any copper oxidation, just a mild cleanser. I cleaned the inside coil about a year ago with the sulfuric acid cleaner spray, it was very dirty, rinsed well with water, the drain line clogged so much stuff came out. I try to replace the filter once a month in the summer, a new one will not make any noise when the system comes on, even a slightly dirty one will make a pop as the airflow is restricted in the return. My options (besides doing nothing) are to replace the outside condensing unit with a replacement (new) R-22 Ruud Weatherking unit, same size as existing 3.5 ton or replace the unit and coil for maximum efficiency. I would assume the old unit is a 10 SEER, the new one would be a 13 SEER. The existing coil is a 4 ton model and my a/c guy said the new R-22 unit will work with it just won't be as efficient without a new coil. However a coil with installation is $900 or so. If I replace both I can go to the new refrigerant, R-410a, which is supposed to work about as well, as R-22 prices may go up in a few years. I plan to sell or rent the house in 5 years time. In both cases it would make sense to upgrade, one is a selling point the other is less headache of it going out on me or a renter. As loud as it is at startup I am betting it will go out soon but I am far from an expert on this subject. It's just a lot of money to throw at something that is technically working ok. If I wait and fix it later I won't get the upfront savings benefits. I don't think the unit qualifies for any tax credits. The payback for upgrade with respect to electric bill savings is within the ownership timeframe on the exterior unit replacement but the payback is several years later for replacing unit and coil. 5 years vs 7 years. $1850 vs $2700. These are friend prices. Cliff Notes: Current a/c works but is loud and inefficient Upgrading outside unit is a 5 year payback I only plan to live here another 5 years Is it worth it to spend $1850 for immediate energy savings and better sleep from quieter operation? |
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Quoted:
Uhh, 2700 for a new AC? I'd do it in a heartbeat, that's incredibly cheap. If you've got a shitty 10 year old A/C and someone offers you a quality install of a whole new SEER 13 unit for $2700, you take it. I agree it's a steal compared to going to a contractor I don't know, but it's still 1/3 of my emergency fund. It would be a cash/check purchase. It's most likely worth it but I have a hard time letting go of money that is not for something mandatory. What about the freon, R-410a since I would do the coil too? |
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Quoted:
If I were buying your home in 5 years I'd reflect the price of a new system to replace a 15yo POS in my offer. 5 YO efficient unit wouldn't be a problem. I replaced two circa 1973 Carrier systems some years back and cut my electric bill by 1/3. I believe that is part of the reason I bought this hooptee as well, the A/C was only 5 years old at the time. For all I know it was this loud when new but somehow I doubt it. I will try to find a cheaper condensing unit, the one I was quoted was $400 more than what I'm seeing online with free shipping. |
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Remember your only going to get about a 20-25 degree temp change from the outside air. If it's 100 outside and 80 inside your doing good.
Don't expect a new unit to do much more because it can't. Also R 22 units come charged with nitrogen now, and you have to buy the R 22 separate. You might save a little money going to a 13 seer but not enough to justify the cost if your old unit is still working. A 10 year old unit is probably a 10 seer not a huge difference. |