Author Topic: Help! I've been told my central A/C needs replacement  (Read 8976 times)

jayholden

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Help! I've been told my central A/C needs replacement
« on: June 23, 2016, 01:41:26 PM »
Hey all. Got some bad news from an A/C repairman today.

I had my A/C set to 78 yesterday and in the afternoon it started blowing room-temperature air. When I investigated I found the pipes leading from the condenser to the home were iced over. After thawing overnight I turned it back on this morning and encountered the same issue.

The repairman came out and said there's a significant freon leak. He recommended replacing the evaporator coil or replacing the entire system - coil, condenser and furnace. I asked him to recharge the freon for now and in the meantime I'd get some second opinions and get back to him.

While waiting on the service pros to arrive and give me a second opinion, I figured I'd post here for some mustachian input. My A/C is a 4-ton SEER 7 20-year-old machine. I plan to move within 5 years. I live in Texas, my wife works from home with our 2-year-old, and it is June, so not cooling the home (somehow) is out. Questions:

1. A lot of A/C companies strongly recommend replacing the furnace along with the condenser. Is this a legit recommendation or a manufactured need? How important is replacing both?

2. I've never done HVAC DIY before. What portions could I feasibly do myself? Obviously I'd need to rely on a pro to legally add the refrigerant.

index

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Re: Help! I've been told my central A/C needs replacement
« Reply #1 on: June 23, 2016, 02:37:41 PM »
AC Seer ratings are based on the entire system. The air handler is part of the furnace so if you replace the AC without replacing the furnace you are not getting the advantage of variable speed etc... With that said, I replaced my AC 20 year old outdoor AC unit and coil but kept the 20 year old furnace. I noticed cooling bills in the summer drop about 40% with only the new outdoor unit and coil.

Prices to replace the AC were all over the map. Find the specific unit you want and ask the HVAC guy to quote you a price with that unit to comparison shop. Even with having the same unit and work priced, my 4 quotes were $2600, $2900, $3400, $5400. So shop around!

zolotiyeruki

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Re: Help! I've been told my central A/C needs replacement
« Reply #2 on: June 23, 2016, 07:11:21 PM »
7 SEER?  Yeah, you'll probably want to replace the outside coil/compressor at least, if not the whole system.  We used to live in Houston, and got a 13 SEER system for about $5k installed, although we were young and stupid and didn't get multiple quotes.  Going from 7 SEER to 13 or 14 would cut your A/C bills in half.

paddedhat

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Re: Help! I've been told my central A/C needs replacement
« Reply #3 on: June 23, 2016, 08:30:16 PM »
I can only speak for my local market area, but we seem to have some of the slipperiest bastards on the planet, when it comes to HVAC repair. I refuse to give a recommendation when friends and neighbors ask me who to call when their AC has issues. I had a neighbor with a 15 YO outside unit that needed help. The first two places he called told him, without even looking, that the unit was shot, and they would charge $4-5K for a new one. The third guy actually inspected the thing, found a bad fan and charged him a hundred bucks to replace it. That honest company was bought out by a bigger outfit.

Several years ago I built a new custom home for a very difficult customer. He insisted on using his own, out of town,  HVAC contractor, and an obscure brand of equipment. Since then, the only "authorized" local repair contractor has screwed this customer out of over $5K in repairs and rework of the system. The entire mess is heading to court since this contractor initially did a few thousand in rework on the ducting,  claiming it was installed incorrectly, then waited a few years and made the same claim again.

I hope it's not a universal issue, but IMHO, I wouldn't do a thing to an HVAC system without three bids and a heck of a lot of due diligence.

jayholden

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Re: Help! I've been told my central A/C needs replacement
« Reply #4 on: June 24, 2016, 06:24:44 AM »
Thanks everyone. When the guy came out he quoted $16k for new everything. So yeah, definitely getting multiple bids.

cockersx3

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Re: Help! I've been told my central A/C needs replacement
« Reply #5 on: June 25, 2016, 06:23:58 AM »
I had my outdoor unit fail a few years ago and had to get it replaced.  One thing that came up for me is the type of freon it used - mine was R-22 since it was older, but nowadays R-410a is primarily used.  Difference is that they don't make R-22 anymore, so that stuff is stupidly expensive since there's only a limited diminishing supply.  If you do go to R-410a, I believe the evap coils in your furnace will need to be compatible with it since it generally operates at a higher system pressure.  In my case my recirc fan / evap coils were 410a compatible per the manufacturer so I didn't need to replace it. 

You said you had a 20 year old unit, so I'm guessing it's R22.  If you do stick with the current furnace, you'll probably want to get some info on whether the coils will work with 410a.  If so, you can probably just get a 410a outdoor unit and keep the existing furnace, with little freon cost.  If your furnace is not 410a compatible, you'll have to either find a R-22 outdoor unit and use R-22 (higher cost for unit and for freon), or replace everything with 410a compatible equipment. 

BlueMR2

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Re: Help! I've been told my central A/C needs replacement
« Reply #6 on: June 26, 2016, 12:36:33 PM »
If your whole system is 20 years old, well, it's considered end of life.  Replacing the furnace as well should at least be considered.

I just had this situation last Summer.  The leak was in the coils in the air handler.  Of course, the A/C is at the bottom of the stack, so the entire furnace has to be removed to get at it.  On my then 19 year and 11 month old system I chose full replacement.  Since it was not yet 20 years it was considered a pre-end of life replacement and I got a $1300 rebate.  At that time the inspector said that he thought the old furnace could easily go another 5 years based on condition, and *possibly* the same for the outside A/C unit, but with the rebate and the fact that most of the labor was going to happen no matter what...

Some other things I learned:
- The average life before failure on A/C is less than 10 years (5 years seems more typical on "cheap" (not well filtered) equipment).  So, there's probably a good case for A/C only repairs there if the furnace is only half-life...
- The old refrigerant is ridiculously expensive, if you're on that, well, more incentive to replace the whole A/C system rather than fix just a portion.
- New furnaces really aren't any more efficient than old ones, don't expect to save money on utilities.  Went from 91% to 96%, savings were lost in the statistical noise.

My choices were:
- Fix just the coil for $2500
- Whole new A/C components for $4500
- Whole new HVAC system for $6900.

SnackDog

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Re: Help! I've been told my central A/C needs replacement
« Reply #7 on: September 11, 2016, 08:49:04 AM »
I would get as many quotes as you can. Specify the exact equipment you need and gets lots of quotes for delivery and install. The cheapest guys can be less than half the average. You want the guy who is new to the business and very hungry. No yellow pages or big ads. Find someone from a recommendation or craigslist. I have always done this and had great service at rock bottom prices. Replaced the whole outdoor unit in Texas for $1500 when most guys wanted $3500.

Kaplin261

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Re: Help! I've been told my central A/C needs replacement
« Reply #8 on: September 12, 2016, 06:59:12 AM »
Check on ebay you can find everything you need to do it yourself $1600. Just hire someone to braze the lineset, pump lineset and release refrigerant ($300)
http://www.ebay.com/itm/3-Ton-13-seer-Goodman-HEAT-PUMP-GSZ13036-ARUF37C14-50ft-Lineset-Tstat-Heat-/111670272334?hash=item1a0011214e:g:lisAAOSwqu9VU6Yp

Ships right to your door. I did this 2 years ago and saved myself $4,000. Watch youtube videos.

zolotiyeruki

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Re: Help! I've been told my central A/C needs replacement
« Reply #9 on: September 12, 2016, 12:06:47 PM »
Check on ebay you can find everything you need to do it yourself $1600. Just hire someone to braze the lineset, pump lineset and release refrigerant ($300)
http://www.ebay.com/itm/3-Ton-13-seer-Goodman-HEAT-PUMP-GSZ13036-ARUF37C14-50ft-Lineset-Tstat-Heat-/111670272334?hash=item1a0011214e:g:lisAAOSwqu9VU6Yp

Ships right to your door. I did this 2 years ago and saved myself $4,000. Watch youtube videos.
Hmmm, that's very interesting.  Can you get packaged A/C and gas furnace units as well?  We're looking to install a second unit for our house, and if I can DIY it, it would accelerate the timeline a LOT.

Kaplin261

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Re: Help! I've been told my central A/C needs replacement
« Reply #10 on: September 12, 2016, 02:16:07 PM »
Check on ebay you can find everything you need to do it yourself $1600. Just hire someone to braze the lineset, pump lineset and release refrigerant ($300)
http://www.ebay.com/itm/3-Ton-13-seer-Goodman-HEAT-PUMP-GSZ13036-ARUF37C14-50ft-Lineset-Tstat-Heat-/111670272334?hash=item1a0011214e:g:lisAAOSwqu9VU6Yp

Ships right to your door. I did this 2 years ago and saved myself $4,000. Watch youtube videos.
Hmmm, that's very interesting.  Can you get packaged A/C and gas furnace units as well?  We're looking to install a second unit for our house, and if I can DIY it, it would accelerate the timeline a LOT.

Gas+AC
http://www.ebay.com/itm/Goodman-2-5-Ton-14-SEER-96-AFUE-60K-BTU-Complete-Split-System-A-C-Gas-/381759598608?hash=item58e2a53010:g:jCwAAOSww4NXqLjL


Took me about a day to install. I pulled the old system out and placed it on the curb with a craigslist ad advertising it was there for free. Make sure all joints with duct work are tight,use plenty of mastic paste and fiberglass tape. Over all this was the easiest $4,000 I ever made and it only took about 10 hours.

J_Stache

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Re: Help! I've been told my central A/C needs replacement
« Reply #11 on: September 12, 2016, 02:58:21 PM »
The proper way to size a system is by using a Manual J calculation.  It's a bit time consuming, so most people will count rooms, approximate square footage and stick a finger in the air before making an educated WAG (wild ass guess).  A company that performs a manual J will at least separate themselves from the cowboys.  Not a guarantee that they won't screw you, but it certainly helps.

piethief

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Re: Help! I've been told my central A/C needs replacement
« Reply #12 on: September 12, 2016, 08:11:39 PM »
AC shops can spray this dye into the freon supply line that will circulate throughout the entire line.  They can then walk around with a black light type thing, and find exactly where the leak is pretty much with pinpoint accuracy.  It may not even be in the coils / outside unit.  I'd have them do the dye test and identify the leak before you shell out for a new unit, especially if you are moving within a couple years.

We had a freon leak in our (granted, it was a new system and under warranty) AC system, and they tracked it to a manufacturing defect from the factory.  The factory replaced the unit with the leak and all has been fine since.

triangle

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Re: Help! I've been told my central A/C needs replacement
« Reply #13 on: September 16, 2016, 12:53:19 AM »
Hopping on an old thread hoping for thoughts on evaluating quotes for hvac replacement. I have a well insulated center unit townhouse with 1500 square feet on three levels and ~35 year old hvac. We've been budgeting for replacement and are ready to make a move. First two quotes are in from well reviewed long established companies who sent out someone who seemed pretty knowledgeable.

The difference in the quotes is about $1200 and seems to be driven by three things. 3 ton v 2.5 ton AC, two stage v single stage gas fired furnace, and brand (Trane or Carrier). Both are 16 seer two stage AC units, 80% AFUE furnaces (making the ventilation work for the higher efficiency ones is tough in this house and likely not worth the cash as small as it is). Any thoughts on whether it's worth paying for larger AC or the more sophisticated control system on the gas furnace?
I am not an expert but I have been looking, pricing and trying to educate myself of this subject as well. As far as the 3 ton vs 2.5 ton, I would have expected them to quote a system the same size as what you currently have unless it was originally spec'd wrong....though I think some of the 0.5 size units are skipped by some manufacturers. 3 ton also sounds like a lot for 1500 square feet.  Both Trane and Carrier make good equipment, but two installers I got quotes from and everything I read on the internet indicated that no system will last that long any more, maybe 20 years if fortunate. 

I would have expected a higher efficiency rating for the two stage furnace, but you are right that the higher efficiency unit means that the existing non-condensing exhaust vent can no longer be used. What I have learned is that the simpler the HVAC system the more reliable it will be. Variable speed fans or compressors may maximize efficiency and comfort but are more expensive and less reliable.

BlueMR2

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Re: Help! I've been told my central A/C needs replacement
« Reply #14 on: September 16, 2016, 09:57:43 AM »
Going 2-stage on the new Lennox I had put in was an efficiency improvement over the single stage.

topshot

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Re: Help! I've been told my central A/C needs replacement
« Reply #15 on: September 16, 2016, 11:11:43 AM »
... 80% AFUE furnaces (making the ventilation work for the higher efficiency ones is tough in this house and likely not worth the cash as small as it is).

Furnace isn't in a basement that you can poke 2" PVC (2.5" diameter really) through the bricks/blocks/whatever?

zolotiyeruki

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Re: Help! I've been told my central A/C needs replacement
« Reply #16 on: September 16, 2016, 12:06:53 PM »
Those EPA rules don't care about payback....look what they did with washing machines---in 2000 washing machines were perfect and would last 20 years... now due to water/energy restrictions the new machines suck so bad I bought a Speed Queen top loader and paid extra for almost the same washer my folks have from 1992..... at least my clothes get clean-- -not that the EPA really cares if your clothes get clean...
Actually, in this case I believe it's the Department of Energy that mandated the increased efficiency.

triangle

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Re: Help! I've been told my central A/C needs replacement
« Reply #17 on: September 16, 2016, 02:41:18 PM »
Is your current system is worth repairing?  While the improved efficiency is very desirable I think the actual energy savings must be small for a town home.

One sales representative I got quotes from did not try to hard sell the variable speed and two stage systems directly but instead said it would save many hundreds of dollars per year on utility bills over the basic systems he could offer from either Trane, Carrier, or Goodman. I don't recall the exact $ figures he was quoting but when I looked at my gas and electric bills over the prior years I realized it was a big oversell. He was stating that the new 90-95% efficient system would save enough over the new 80-85% efficient system to it pay for itself fairly quickly, but that did not add up when compared to what my current system (natural gas furnace) used which was 70-80% efficient.  [[Note I may not be stating those % efficiency ratings precisely, just ball park from what I remembered of the discussion]]

A second sales rep quoted me their systems from Trane and Carrier and was much more straightforward about everything. Offering the more expensive high efficiency systems but admitting they don't save much money if any over their lifetime over the more basic units which were already pretty efficient.

Jack

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Re: Help! I've been told my central A/C needs replacement
« Reply #18 on: September 16, 2016, 03:01:24 PM »
Actually, in this case I believe it's the Department of Energy that mandated the increased efficiency.

How weird. As far as I knew, the Department of Energy mainly concerned itself with nuclear stuff.

topshot

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Re: Help! I've been told my central A/C needs replacement
« Reply #19 on: September 16, 2016, 09:04:08 PM »
Depending on climate a 80% furnace is quite enough....esp if you consider the expense of initial cost and expense of  fixing it

I was looking at the on demand water heaters to replace the 40 gallon tank heater I have now... the expense and headache of figuring out how to increase the gas supply and deal with the venting... no payback at all....

On tankless water heaters I agree with you. I passed on that even though that is what I wanted. Even a normal gas water heater was more expense than I wanted because of the venting I'd need. But upgrading to a smaller 95% furnace was a no brainer to me. I even took out a great 80% unit that was only 10 years old to do it. I will admit I would not have bothered if it weren't for the fact I wanted to use the chimney space for ductwork and plumbing. But when I could get my unit for < $900 and get a $400 rebate from the gas company, it paid for itself in less than a year (but I also have better insulation).

triangle

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Re: Help! I've been told my central A/C needs replacement
« Reply #20 on: September 17, 2016, 05:25:06 PM »
...
My early 80s unit running on obsolete coolant which fails to keep the place cool is def not worth repairing! Home inspector said to budget for it ASAP, we'd be lucky to get a year out of it and that was a few years back!
Good luck with your new choice. My unit is not much younger than yours and recently was recharged with a few pounds of coolant, the first time any has ever been added as far as I know. But the need for total replacement is no doubt approaching. 

In a related story, I believe older Freon formulation smuggling is still a very big problem, maybe only second to illicit drugs.

triangle

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Re: Help! I've been told my central A/C needs replacement
« Reply #21 on: September 19, 2016, 01:33:03 PM »
...
Our water heater has ages left on it but we would consider the tankless for replacement when the time comes- likely not worth it if we have to increase line capacity (a friend of mine installed one without the upgrade and the water is never really hot). Nice in theory though.
...
We had a tankless water heater installed about 8 years ago when natural gas prices were higher. Beyond the economic and environmentally friendly motivations another reason was to move it out of the attic into the crawlspace. Imagine being away from home while the tank leaks from above. :-( The water does seem to take a little longer to get hot at the faucet, my suspicion is that it is mainly due to there not being a mass of heat sitting at the head of the pipe run keeping the pipe run a little warmer.

But IMO the biggest concern by far that someone should consider before installing a new tankless hot water heater is the minimum flow rating. Which is the minimum amount of hot water flowing through the unit before it will fire up and actually heat water. Today's new units may have a wider operating range and flexibility but mine does not flame up until about 0.6 gallons/minute are flowing. Which may not sound like very much but I do not need that much hot water when washing my hands or even taking a shower. In order to compensate we turned down the hot water temperature so that very little cold water is needed to mix in when taking a shower, but then other users such as the dishwasher and washing machine are compromised. The root problem is having it "sized" for a 3 bedroom, 4-5 person household so that multiple usage could happen simultaneously without any loss of hot water. But the downside is that a single person may need to use extra water just to get the unit started. Which negates any environmental or economic savings. A smaller size unit would have been okay.