Carrier A-coil vs N-coil

[steve f]

Still talking with salesmen about getting estimates for a new system.

A second Carrier salesman came out today to give an estimate. In talking about AC effeciency he mentioned one issue was that the closet where the current AC is located doesn't have enough height for an A coil, so they'd have to use an N-coil, and this would cut the SEER rating a little. He stated that Carrier didn't even stock the A-coil in this area since it required so much height and so few people were able to use it. He said all AC units, not just the super efficient ones, used basically the same size A-coil, so an A-coil was out of the question no matter what AC I chose.

I measured the height of the closet, and it's a bit over 8.5 feet. It's actually an unfinished closet in the basement that's 7.5 feet long and 40 inches wide, with a water heater in one end and the AC in the other. After reading about some of the difficulties people people had with really tight spaces, I was feeling pretty good about my layout, until now.

Could someone explain the advantages/disadvantages of Carrier A-coils vs N-coils? What are the options here? There's another closet next to this one that could be used if it's really necessary to expand.

[RyanHughes]

I see Carrier's N-coils quoted almost always, likely for that reason. A-coils with Carrier run anywhere from 3-8" higher depending on size. I wouldn't worry about the SEER rating too much--just a quick check shows that it isn't hurt too much. Also, higher nominal coil sizes can be used to gain a little efficiency.

[steve f]

I see Carrier's N-coils quoted almost always, likely for that reason. A-coils with Carrier run anywhere from 3-8" higher depending on size. I wouldn't worry about the SEER rating too much--just a quick check shows that it isn't hurt too much. Also, higher nominal coil sizes can be used to gain a little efficiency.

Thanks for the reply, again. I'm aware that there are no stupid questions, only stupid people, but inspite of that I really like to try understand things when I do something like this. Thankfully places like this make it possible to get answers.

The first Carrier salesman gave me a quote on a 2 ton system, but included a 2.5 ton coil because it would increase efficiency he said, which kind of jibes with what you're saying, I think.