Might replace central A/C and have questions

[WannaFly]

My house, ~1200sq ft - has a very old central a/c unit- I am contemplating having it replaced and wanted to see if anyone here had any advice or insight if they have been through the process.

My main concern is, looking at reviews of a/c, this site: http://www.furnacecompare.com seems to be one of the more comprehensive list of reviews. I'm having a hard time believing that so many people have problems with them, most if not all the companies only have an average rating of 2 or 3 out of 5. I know it might be a situation of reviews are only made when problems arise, and that a lot of problems arise from problems with installers -but how can I find information about which brand/model might be better/more reliable etc?

I have one company coming out to provide me an estimate just so i have a range of what it might cost, and they only sell carrier or amana - my instincts tell me to go with name brand, but according to the reviews they both seem about the same.

I've read that a "Manual J" calculation should be done to determine the size of the A/C, how recommended is that? From what I've heard most just go by sq st. Has anyone had this done?

 

[highland145]

Mine wasn't on the list, less than 1 year old. Nordyne manufacturer badged under Frigidare, Nutone and one other I can't remember. So 2 brands may be the same unit.

Today will be the 3rd trip to add freon and try to find a f-n leak. Warranty up next month so guess I get the screw after that.

 

[spidey07]

Get Trane or Carrier, avoid all else. Don't forget about the tax credits, pretty sure they are still in effect if you get an energy efficient one.

 

[DaveJ]

My house, ~1200sq ft - has a very old central a/c unit- I am contemplating having it replaced and wanted to see if anyone here had any advice or insight if they have been through the process.

My main concern is, looking at reviews of a/c, this site: http://www.furnacecompare.com seems to be one of the more comprehensive list of reviews. I'm having a hard time believing that so many people have problems with them, most if not all the companies only have an average rating of 2 or 3 out of 5. I know it might be a situation of reviews are only made when problems arise, and that a lot of problems arise from problems with installers -but how can I find information about which brand/model might be better/more reliable etc?

I have one company coming out to provide me an estimate just so i have a range of what it might cost, and they only sell carrier or amana - my instincts tell me to go with name brand, but according to the reviews they both seem about the same.

I've read that a "Manual J" calculation should be done to determine the size of the A/C, how recommended is that? From what I've heard most just go by sq st. Has anyone had this done?

Brand is much less important than a quality install. Check www.servicemagic.com or Angie's List for good installer recommendations. Definitely also get a Manual J done, you can size by square foot but it won't be as accurate. Any contractor who won't do a Manual J isn't worth dealing with.

 

[Vette73]

I agree with DaveJ, its the install not the name that really matters.

Most electrical parts of a AC system are made by GE or Honey well. The rest is fabbed (coils and such) by the name brand makers. So the biggest good-bad of a unit is who and how it is installed.

I just got done putting in a 5ton ac and 125k furance. AC is 14 or 15 SEER and Heat is 93% or so. Its a comfortmaker brand if it matters.

So get a good SEER rating, 14 or higher, and have it installed by someone that does good work and follow through and is not cutting corners.

 

[WannaFly]

Thanks for the info. I'll definitely research the contractor/company more before i make any decisions. I'd like to get a 16 SEER to qualify for the tax incentive, but and concerned about cost. I have a company coming out thursday, hopefully they will do the manual J.

spidey07: any reason you recommend those two companies?

 

[spidey07]

Thanks for the info. I'll definitely research the contractor/company more before i make any decisions. I'd like to get a 16 SEER to qualify for the tax incentive, but and concerned about cost. I have a company coming out thursday, hopefully they will do the manual J.

spidey07: any reason you recommend those two companies?

Buddy does HVAC and that's what he told me when we were looking to get a new unit. He had no vested interest in it because I don't mix business and friendship. The trane AC unit put on my wife's house is HUGE for the size of the home, 1500 sqft. The coils are easily twice the size of the unit on my 3000 sqft home. It does very little work to keep her house cool and she saw a very large reduction in energy bills.

She went with a model above middle of the line, but not quite top of the line in SEER. 6000 for ac/heat/blower installed and some ductwork, then got 1500 back in tax credit.

 

[highland145]

Thanks for the info. I'll definitely research the contractor/company more before i make any decisions. I'd like to get a 16 SEER to qualify for the tax incentive, but and concerned about cost. I have a company coming out thursday, hopefully they will do the manual J.

FWIW:Think it's 14 seer. That's what I put in and got the credit. Unless it's changed.

 

[WannaFly]

spidey: Great, thanks a lot that was the kind of info and experience i was looking for.

highland: depends on what type of system, I have a split system:
Requirements

Split Systems:
SEER ≥ 16
EER ≥ 13

Package systems:
SEER ≥ 14
EER ≥ 12
SEER ≥ 14

 

[DaveJ]

FWIW:Think it's 14 seer. That's what I put in and got the credit. Unless it's changed.

When I got my heat pump replaced in March it was 15 SEER/12.5 EER/8.5 HSPF minimum to qualify for the tax credit. Straight AC units are 16 SEER/13 EER minimum IIRC.

WannaFly, I also forgot to mention that there's a great PDF available from acca.org for evaluating contractors that bid on your install. The file is available here.

Get your contractor to give you specific model numbers for the condenser and blower/evap coil, and once you have those you can look up the model combo in the AHRI directory here to verify that it qualifies for the tax credit.

 

[highland145]

WF & Dave. Didn't realize there was a difference. Got a heat pump package and the $$ credit. Now if they can fix the leak.

So if I get some crack head to steal the copper and I have to buy a new unit, can I get the credit twice? No reply necessary, just wishful thinking.

 

[BUTCH1]

Buddy does HVAC and that's what he told me when we were looking to get a new unit. He had no vested interest in it because I don't mix business and friendship. The trane AC unit put on my wife's house is HUGE for the size of the home, 1500 sqft. The coils are easily twice the size of the unit on my 3000 sqft home. It does very little work to keep her house cool and she saw a very large reduction in energy bills.

She went with a model above middle of the line, but not quite top of the line in SEER. 6000 for ac/heat/blower installed and some ductwork, then got 1500 back in tax credit.

Generally most installers will advise you NOT to go too big as the unit won't run enough to dehumidify the home.

 

[mshan]

Yes, I also read that if you get too big hvac, then it turns on, cools quickly, then turns off quickly, rather than running in a more sustained and I believe more optimal manner.

I read rule of thumb years ago, I forgot specifics, but it may have been $1500 - $2000 per ton of cooling capacity.

 

[nickbits]

Generally most installers will advise you NOT to go too big as the unit won't run enough to dehumidify the home.

Depends what you mean by "big"--tonnage or physical size. High SEER units are a lot larger because of the increased surface area.

 

[BUTCH1]

Depends what you mean by "big"--tonnage or physical size. High SEER units are a lot larger because of the increased surface area.

True, I thought someone installed a unit with twice the BTU needed, I wouldn't know about the bigger coil size, mine is a 10 seer.

 

[MarkXIX]

Concur on the "it's the install, stupid" notion mentioned above.

Simply put, DO NOT let them reuse the copper feed lines. I found in my research, and talking with my brother (who is a plumber, who has certified HVAC guys on staff) that this was the most common issue. New refrigerants have a lower tolerance to contaminants in the lines.

At first, their HVAC guy told my brother to just use a cleaning kit on my lines in the house rather than rip out dry wall to replace them. I told my brother what my research said, and when he told his HVAC guy that it was a job for family, he said, "Well fuck man! You shoulda told me to begin with. Replace the feed lines with brand new, or he'll be needing a new condenser in about 5 years versus 10." That's consistent with what I read and that's what we did.

Fifty foot of feed line brand new is a drop in the bucket compared to your A/C failing. I also found that each HVAC guy has preference for certain brands based solely on how they get installed. Some vendors have hookups, wiring, etc., that are easier to tie into than others based on your skills as an HVAC guy. You will get a different answer from just about every installer on brand name, which means they're all the same, the quality of the install is what counts.

 

[Chaotic42]

I replaced a unit from 1979 (D when I bought my house in 2008. Mine is a Goodman, and it is certainly performing well, but in hindsight I'd have gone with a Trane. I live in a very humid area, so I got a 2.5 ton for my 1050 square foot house.

Definitely ask around about installers. A central AC unit can affect your resell rates and your general happiness, so don't skimp.

 

[Vette73]

Concur on the "it's the install, stupid" notion mentioned above.

Simply put, DO NOT let them reuse the copper feed lines. I found in my research, and talking with my brother (who is a plumber, who has certified HVAC guys on staff) that this was the most common issue. New refrigerants have a lower tolerance to contaminants in the lines.

At first, their HVAC guy told my brother to just use a cleaning kit on my lines in the house rather than rip out dry wall to replace them. I told my brother what my research said, and when he told his HVAC guy that it was a job for family, he said, "Well fuck man! You shoulda told me to begin with. Replace the feed lines with brand new, or he'll be needing a new condenser in about 5 years versus 10." That's consistent with what I read and that's what we did.

Fifty foot of feed line brand new is a drop in the bucket compared to your A/C failing. I also found that each HVAC guy has preference for certain brands based solely on how they get installed. Some vendors have hookups, wiring, etc., that are easier to tie into than others based on your skills as an HVAC guy. You will get a different answer from just about every installer on brand name, which means they're all the same, the quality of the install is what counts.

Yea always replace the copper lines. Newwer systems run at a higher pressure (r134a) and will blow out a old line if it has issues.

 

[BUTCH1]

Concur on the "it's the install, stupid" notion mentioned above.

Simply put, DO NOT let them reuse the copper feed lines. I found in my research, and talking with my brother (who is a plumber, who has certified HVAC guys on staff) that this was the most common issue. New refrigerants have a lower tolerance to contaminants in the lines.

At first, their HVAC guy told my brother to just use a cleaning kit on my lines in the house rather than rip out dry wall to replace them. I told my brother what my research said, and when he told his HVAC guy that it was a job for family, he said, "Well fuck man! You shoulda told me to begin with. Replace the feed lines with brand new, or he'll be needing a new condenser in about 5 years versus 10." That's consistent with what I read and that's what we did.

Fifty foot of feed line brand new is a drop in the bucket compared to your A/C failing. I also found that each HVAC guy has preference for certain brands based solely on how they get installed. Some vendors have hookups, wiring, etc., that are easier to tie into than others based on your skills as an HVAC guy. You will get a different answer from just about every installer on brand name, which means they're all the same, the quality of the install is what counts.

Hmm, copper is copper unless the new system specifies a different diameter tube or the old is in bad shape anyway. Don't see why a length of tubing can't be flushed but make sure the estimate for your install includes this, it might be based on re-using the existing feed and return lines..

 

[Rubycon]

Old copper may have been sweated with lead solder instead of brazed with silver-phosphor alloy which is MUCH stronger.

Pulling a GOOD vacuum for a day will be sufficient for any "cleaning" of the lines unless a severe compressor burnout was encountered where acidic oil may be present. The installation of a decent filter/dryer takes care of that, however.

RE: compatibility - refrigerants may not be compatible with the oils used in older compressors.

 

[Vette73]

Old copper may have been sweated with lead solder instead of brazed with silver-phosphor alloy which is MUCH stronger.

Pulling a GOOD vacuum for a day will be sufficient for any "cleaning" of the lines unless a severe compressor burnout was encountered where acidic oil may be present. The installation of a decent filter/dryer takes care of that, however.

RE: compatibility - refrigerants may not be compatible with the oils used in older compressors.

Yep old Freon was R22 newwer ones use r134a. The oils I am sure are very different.
That and new copper lines are minor cost when replacing a system. Its like rebuilding your engine in a car but using the old oil filter.

 

[BUTCH1]

Yep old Freon was R22 newwer ones use r134a. The oils I am sure are very different.
That and new copper lines are minor cost when replacing a system. Its like rebuilding your engine in a car but using the old oil filter.

Not really, an oil filter is a $3 item and takes 30 seconds to install. Copper is not cheap and if installing new involves lots of more time it's gonna effect the final price of the install, OP I would make sure your estimate includes this lest you get a nasty surprise when you get the invoice..

 

[Rubycon]

Not really, an oil filter is a $3 item and takes 30 seconds to install. Copper is not cheap and if installing new involves lots of more time it's gonna effect the final price of the install, OP I would make sure your estimate includes this lest you get a nasty surprise when you get the invoice..

Perhaps he uses WIX filters.

 

[WannaFly]

Great discussion on replacing the lines - the company coming thursday said they WONT run new equipment on old lines, so yes they'll rerun them. I'll do a lot of research on the company and make sure to get good references on the company i choose.

 

[MarkXIX]

I did learn from my brother though that they salvage the copper, turn it in for scrap and make good "pocket change" off the deal. He was quite happy when we used only about half of the 50 foot that we bought for the job because he would be able to put some beer in his fridge at home.