I am currently in the process of getting quotes on a new AC Unit. I am looking at a 2.5 ton, 13/14 seer unit. When talking to the guys who do the quotes I have gotten mixed answers on a couple things. My unit is 18 years old and the motor broke.

1. If I get a new AC unit for the outside that is 13 or 14 seer. Do I need to buy a new coil?

2. Also is it better to replace both the AC and furnace at one time, or is it okay to replace the AC unit now and then replace the furnace when it is broken?

3. I have had 4 different estimators out and I have gotten 3 different quotes with different size units. How do I know for sure what size unit I need?

Thank you for all of your help.

. If I get a new AC unit for the outside that is 13 or 14 seer. Do I need to buy a new coil?
YES, the need to match to get full effect of all it can do.

2. Also is it better to replace both the AC and furnace at one time, or is it okay to replace the AC unit now and then replace the furnace when it is broken?
NO, if furnace is working fine and doing its job,no need to replace at this time


How do I know for sure what size unit I need
If they know what they are doing and do the right calculations (schedual J) they can figure it right without guessing,, they will take into consideration ,1.how well insulated,to the type of windows you have,3 the square footage of living space... 4. the size and condition of your duct work,, has any of them did this before giving you a quote?

I am currently in the process of getting quotes on a new AC Unit. I am looking at a 2.5 ton, 13/14 seer unit. When talking to the guys who do the quotes I have gotten mixed answers on a couple things. My unit is 18 years old and the motor broke.

1. If i get a new AC unit for the outside that is 13 or 14 seer. Do i need to buy a new coil?

2. Also is it better to replace both the AC and furnace at one time, or is it okay to replace the AC unit now and then replace the furnace when it is broken?

3. I have had 4 different estimators out and i have gotten 3 different quotes with different size units. How do i know for sure what size unit i need?

Thank you for all of your help.


Here is a bit more info for you


I think most home owners will understand if you give them something they can see.
Show the factory charge on the unit they have, then the charge on the new unit.
Most will read as stated below, I think.
I’m just looking for ways to help justify Coil with condenser. This may help?

Nominal Three Ton System.

A heat pump outdoor unit manufactured in 1995 took a 125oz. Charge of R-22.
A heat pump outdoor unit manufactured in 2004 took a 200oz. Charge of R-22.

On the heat pump outdoor unit alone there is a volume mis-match of 1.6.
Meaning, the volume of Refrigerant held in a unit manufactured in 2004
Is 1.6 times that of a unit manufactured in 1995.

On an indoor coil manufactured in 1995 the face area of a
Coil was 3.8 sq. ft. at 13 fin/inch, 3 rows deep.
On an indoor coil manufactured in 2004 the face area of a
Coil was 4.38 sq. ft. at 14 fin/inch, 3 rows deep.

As you can see the coils are very different!

These may also be of help in a decission.

Can I put a 3ton 14seer condensing unit on a 4ton evap coil withcapilary metering device