I'm a homeowner looking to have AC added to a ~4 yr old, single story, 2195 sq ft house w/ central heating (it is a carrier--5 ton, i believe--gas furnace that resides in the attic).
i have had a couple of HVAC professionals come in and give me quotes for adding AC and media-type air cleaner to the existing furnace and ducting.
Both have recommended a Bryant 534ANR048 13-SEER 4-ton streamline condenser unit (the site i selected for installation has some constraints) along with an Allstyle plenum coil added to the existing ducting.
One specified the coil as an "All Style ductboard coil, M# ALSB048" and the other listed the ASFM4821.
I have two questions:
- Neither company performed Manual J calculations to arrive at the size of the unit; instead, they both "estimated".. indicated that the full calculations required 2 hrs to perform and were unnecessary. Is this is common practice for HVAC installations and are such rules of thumb are likely to be accurate? Certainly both these companies appear experienced in their trades but this is the first time i've ever had to add AC to an existing home and I'd hate to have them get the system sizing or overall design wrong.
- What's the professional consensus around the specific condenser recommended by these companies? Are there other alternatives (besides the equivalent Carrier unit) that have the same (small) footprint? Are there any noteworthy differences between this and the Carrier?
- Re: the coils, I've read on this site that the Allstyle coils are considered builder grade and not high quality. Are there any alternative types of coils that may be better matched to the rest of the system?
- I haven't been able to find any information about these two specific coils on the Allstyle site. Are there any noteworthy differences between the two types of coils that have been recommended (ALSB048 vs ASFM4821)?
thanks for any help or feedback you can provide,