Home Air Conditioner Replacement Cost

[Bones81]

So I live in Houston and my house has 2 AC units since it's your typical vertical townhouse (4 floors total).  The AC unit that serves the bottom 2 floors has a leak which the repairman has said would be difficult to find and since the AC unit is 10 years old, he recommends replacing the unit with a new one.  I've done some research and found some formulas that take into account cost of repair, the age of the system and the cost of a new system and it looks like a new unit may be the route to go.

However, the quote I received from the AC company was $8,600 all-in to replace the unit. This sounds high to me so I did some more research and actually paid a few bucks to use ASM's HVAC Design and Consultation Program which you basically plug in the AC unit you want and some other info on your house and it spits out a range of what the job should cost.  Using the estimate from this program, the job should cost $4,800 - $5,900. 

I wanted to see if there was anyone out there who had some expertise on this.  The AC company's $8,600 quote was for:

3.5 ton 16 seer American Standard complete system
Condenser with new slab
whip and disconnect
return air plenum
matching slab evaporator coil
plenum with collars and dampers
emergency pan with float switch
rerun accessible drain lines

The ASM estimate program gave me the following:
3.5 ton 16 Seer American Standard AC unit - $1,761.05
Labor - $321.60
Other Materials - $912.00
Liability & Workers Comp Insurance and Fees, etc. - $681
Total Contractor Cost - $3,675.65
30%-60% profit margin - $4,778 - $5,881

Am I missing something on the difference in the costs? Thanks

[JLee]

I would get several more quotes.

[extremedefense]

I'd look into replacing your system with a mini split system. It costs more upfront but the energy costs are so much lower.

[Bones81]

I would get several more quotes.

I've reached out to 3 or 4 on Angie's List.  Haven't had any responses yet.  Hopefully soon. 

[405programmer]

Unless the supply or return plenum are damaged I would be very hesitant to replace or alter them. Also your estimate didn't look like it included the evaporator coil for the inside unit. That would probably be ~800 in material cost. So add that in to the pre-margin calculation. I would guess that all the quotes you're going to get this time of the year are going to be slightly inflated because AC companies stay very busy this time of year.

Also is your AC configured in a multi-zone system? Do you have 2 thermostats or 4? If the initial quote included setting up the lower system to go from single zone to multi zone I could see that easily adding $1000-1500 to your final quote price.

[Bones81]

Unless the supply or return plenum are damaged I would be very hesitant to replace or alter them. Also your estimate didn't look like it included the evaporator coil for the inside unit. That would probably be ~800 in material cost. So add that in to the pre-margin calculation. I would guess that all the quotes you're going to get this time of the year are going to be slightly inflated because AC companies stay very busy this time of year.

Also is your AC configured in a multi-zone system? Do you have 2 thermostats or 4? If the initial quote included setting up the lower system to go from single zone to multi zone I could see that easily adding $1000-1500 to your final quote price.

Right now there are 2 thermostats, one for each unit.  One controls the temp on the 1st two floors, the other for the 3rd and 4th floors. 

[GuitarBrian]

Order the unit(s)/parts yourself and find someone to install it. That way you are only negotiating the labor. I wouldn't change the plenum unless it is damaged.

Stop paying ridiculous profit margins on materials. Pay the tech for his labor.

I get new 3 ton Goodman heat pumps installed with new air handler and coil for $1500 parts & $800 labor. A straight cool would be cheaper.

[Bones81]

Order the unit(s)/parts yourself and find someone to install it. That way you are only negotiating the labor. I wouldn't change the plenum unless it is damaged.

Stop paying ridiculous profit margins on materials. Pay the tech for his labor.

I get new 3 ton Goodman heat pumps installed with new air handler and coil for $1500 parts & $800 labor. A straight cool would be cheaper.

I'm all for that, I just don't know anything about AC units.  I have a good idea about what I need as far as tonnage and SEER rating, I just don't know if the unit comes with everything I'll need.   

[GuitarBrian]

Ok. Let's see... I assume this is a split system vs a package unit. You have a condenser outside and a coil inside.
Your coil, is it a standalone unit? Meaning it has it's own fan? People with gas or propane heat might have a coil box. Generally square ish, with no fan and you use the heater fan... You'll need to know which one you have so you can get the right one.

Is your condenser pad bad? You can DIY a concrete pad for $20 easy... Or get a new plastic one.

Where does the condensation line drain to? Your quote included an emergency pan and float switch. Do you have this already? Is this something you feel you need? I don't use this on any of my units... But they all drain outside... If you are concerned with your line backing up and getting something wet... Maybe... If you haven't had problems, I'd leave well enough alone.

Once I know what type of coil you need, I can point you to a supplier.

[Bones81]

Ok. Let's see... I assume this is a split system vs a package unit. You have a condenser outside and a coil inside.
Your coil, is it a standalone unit? Meaning it has it's own fan? People with gas or propane heat might have a coil box. Generally square ish, with no fan and you use the heater fan... You'll need to know which one you have so you can get the right one.

Is your condenser pad bad? You can DIY a concrete pad for $20 easy... Or get a new plastic one.

Where does the condensation line drain to? Your quote included an emergency pan and float switch. Do you have this already? Is this something you feel you need? I don't use this on any of my units... But they all drain outside... If you are concerned with your line backing up and getting something wet... Maybe... If you haven't had problems, I'd leave well enough alone.

Once I know what type of coil you need, I can point you to a supplier.

Yes, split system, I believe the coil has its own fan but will confirm.  I have 3 different companies coming out tomorrow to give me their opinions, so I'll figure out exactly what I'll need.

Condenser pad should be ok, there are 2 condensers sitting on it, so they'd have to disconnect the 2nd one and move it if they were going to put down a new pad.  There used to be a problem with water running under and eroding the area under the slab, which potentially could have led to it cracking but I re-routed the water away from there.   

Condensation line just extends a few inches outside the house and drains into the yard (the unit is up in the attic on the 4th floor).  It works because when new refrigerant was added the other day, there was a ton of water dripping into the yard.  The emergency pan and switch are already there, so I don't know why they included that in the quote. 

I'll let you know what the other AC guys say tomorrow and figure out exactly what all I'll need.

[GuitarBrian]

If you use a air handler and coil package, this would be where I would start.

http://www.ebay.com/itm/111366899560

These guys also have a website, and I have bought from them before. It worked out.

Once you have the unit. You can begin to call technicians. You want to find a licensed company, and I would expect to pay ~1,000. They will pump down the old unit (this puts all the refrigerant in the condenser), cut the refrigerant lines. If the existing until is r22, they will wash refrigerant lines, if it was 410a, then no washing needed.
They will remove the air handler/coil, then install the new one. Brazing the refrigerant lines to the new unit.
The new condenser will be placed, and lines brazed.
If you need a new whip and disconnect box it will be installed now.

[Bones81]

If you use a air handler and coil package, this would be where I would start.

http://www.ebay.com/itm/111366899560

These guys also have a website, and I have bought from them before. It worked out.

Once you have the unit. You can begin to call technicians. You want to find a licensed company, and I would expect to pay ~1,000. They will pump down the old unit (this puts all the refrigerant in the condenser), cut the refrigerant lines. If the existing until is r22, they will wash refrigerant lines, if it was 410a, then no washing needed.
They will remove the air handler/coil, then install the new one. Brazing the refrigerant lines to the new unit.
The new condenser will be placed, and lines brazed.
If you need a new whip and disconnect box it will be installed now.

Thanks!  I had 3 different companies come out on Wednesday and pretty much figured out that a new coil and float switch (there presently isn't one) is all I need since the vast majority of the time the leak is in the coil.  Existing unit uses 410a, so no issues there. The furnace is fine and so is the condenser and the pad it sits on outside.  One company quoted $3,600 for a Lennox or American Standard coil only while another quoted $3,750 for the coil and a 14 seer Bryant condenser. 

Poking around on Ebay, I found some coils for ~$360 ish like this Goodman:

http://www.ebay.com/itm/Goodman-Evaporator-Coil-Full-Cased-CAPF3642C6-Upflow-or-Downflow-3-5-Ton-/152583423673?epid=1100530926&hash=item2386ae46b9:g:ySsAAOSwzJ5XUGee

The existing unit is a Carrier, not sure if you can mix and match furnaces and coils or if it's ok as long as they're the same tonnage.  Not sure what labor would be, if it's ~$1,000 for a whole new system, perhaps I could have a coil done for a few hundred?

This Goodman complete system looks great.  From what I've read, the manufacturer has good reviews.  Although the furnace and condenser don't need to be replaced right now, they are 10 years old and I think the condenser is an 8 seer.  Given the age of the existing system and the energy savings of a new one, it might be worth it to replace everything.  If I can get the labor done for ~$1,000, I'd be getting a whole new 16 seer system for ~$3,000.  A couple of companies said they would do the labor if I bought the equipment myself.  I can see what they'll quote me once I decide which route to go.

Does this sound right or am I missing anything?

Thanks again for all the help Brian.   

[GuitarBrian]

I have been up hunting... Just came down the mountain with my phone... Hopefully you figured out what you needed. I have mixed coils and condensers in the past, but would consult a tech familiar with both before I buy... Several important variables.
I do know that a SEER rating is not valid unless you match a system. Since manufactures will sometimes use an undersize condenser and large coil to get to 14 seer of 16 or whatever, or the other way around.
Good luck.

I have had good luck with Goodman units.

[GuitarBrian]

I got a chance to look at the eBay listing... If the tons match, it should work OK. Don't count of the SEER rating of either condenser of coil. It will end up near the lower of the the 2.

I have mixed and matched condenser and coil brands before with good results.

You can find a new system with a cased coil instead of the stand alone one I linked, if you decide to go that route...