New system sizing

[Jshanl]

I have a question for you residential guys as residential systems are not any thing that I,ve spent much time working on and you guys are the pros. I'm going to replace my 10 SEER system with a 16- 18 SEER system and I need a little help. I know they do not make half size units,what I currently have is an 2.5 ton split system. I got conflicting answers at two supply houses on what size coil to use. One quoted me a three ton cond and 3 to 4 ton evap.Another supply house quoted me a 3 ton cond and a 4-5 ton evap.

[BaldLoonie]

Use whatever coil the manufacturer calls for. Check their specs or www.ahridirectory.org to be sure. Often on high SEER, huge coils are needed so going to a "4-5 ton" coil for a 3 ton outdoor unit may be right.

[pecmsg]

Manual J is the only proper way to size your equipment

[wahoo]

Ask them (the supply house) to show you the ARI match up sheet and then you can verify you're getting the efficiency you want. To get into the 16-18 SEER range, you usually need to increase the indoor coil size quite a bit! Supply houses sometimes don't check this too well in my experience. But they'll give you a copy of ARI match sheet if you ask (normally).

[lancerbomb08]

agreed with everyones post hear....higher seer, bigger evap coil

[fxb80]

Personal example: Coleman 18 SEER 36,000BTU outdoor unit with a 43,000 BTU indoor coil. Actual SEER rating 17.1. Think I could have gotten 17.4 if I had gone to a full 4 ton matched coil but didn't because of the physical size.