Huskers21
10-03-2008, 11:18 AM
I am in the process of replacing my split system HVAC equipment for an 1800 SF, three-level townhouse in the Washington DC area. Several local contractors have inspected the original system (20 yrs old, 2-ton A/C), discussed my options and provided recommendations for me to review. I have narrowed the proposals down to 2 systems based on comfort level/reputation of each contractor, equipment performance, NCI certified installers and great advice from this forum.
Although I would be satisfied with either contractor and the price/warranties are essentially the same, I was hoping to get your professional opinions as to which system would be the better purchase in terms of overall performance and energy efficiency.
OPTION 1:
A/C Unit: Trane XL15i (4TTX5030A1000A) *single phase
Furnace: Trane XV-80 (TUD080R9V3K)
Coil: Trane AlumaTuff (4TXCB031BC3HCA)
Humidifier: Trane THUMD300
T-Stat: Honeywell VisionPro IAQ
OPTION 2:
A/C Unit: Carrier Infinity 24ANA7 (24ANA724A003) *two stage
Furnace: Carrier Infinity 58CVA (58CVA070-1-12)
Coil: Carrier (CNPVP024 14")
Humidifier: Honeywell HE365
T-Stat: Carrier Infinity (SYSTXCCUID01)
No “Manual J” calculation was performed by any of the contractors although they did ask if any exterior changes have occurred since the original heat load was documented during the county permit process. With no envelope changes, I presume that the original heat load is acceptable for their use. Given that my current system is sized for 2.0 tons of cooling, I questioned the recommendation for 2.5 tons in Option 1 and was told that the increased cooling would benefit the top level of my townhouse which does get warm during the hot summer months and that my ducts were already sized appropriately to accommodate the difference. Would the extra 0.5 tons be a concern for short cycles and decreased humidity control if I went with this recommendation? The other noticeable difference in the A/C unit is the single phase compressor in Option 1 versus the two stage compressor in Option 2. Even though both furnaces have a variable speed blower motor, does the two stage compressor provide a clear advantage?
Thank you in advance for your time and assistance.
Although I would be satisfied with either contractor and the price/warranties are essentially the same, I was hoping to get your professional opinions as to which system would be the better purchase in terms of overall performance and energy efficiency.
OPTION 1:
A/C Unit: Trane XL15i (4TTX5030A1000A) *single phase
Furnace: Trane XV-80 (TUD080R9V3K)
Coil: Trane AlumaTuff (4TXCB031BC3HCA)
Humidifier: Trane THUMD300
T-Stat: Honeywell VisionPro IAQ
OPTION 2:
A/C Unit: Carrier Infinity 24ANA7 (24ANA724A003) *two stage
Furnace: Carrier Infinity 58CVA (58CVA070-1-12)
Coil: Carrier (CNPVP024 14")
Humidifier: Honeywell HE365
T-Stat: Carrier Infinity (SYSTXCCUID01)
No “Manual J” calculation was performed by any of the contractors although they did ask if any exterior changes have occurred since the original heat load was documented during the county permit process. With no envelope changes, I presume that the original heat load is acceptable for their use. Given that my current system is sized for 2.0 tons of cooling, I questioned the recommendation for 2.5 tons in Option 1 and was told that the increased cooling would benefit the top level of my townhouse which does get warm during the hot summer months and that my ducts were already sized appropriately to accommodate the difference. Would the extra 0.5 tons be a concern for short cycles and decreased humidity control if I went with this recommendation? The other noticeable difference in the A/C unit is the single phase compressor in Option 1 versus the two stage compressor in Option 2. Even though both furnaces have a variable speed blower motor, does the two stage compressor provide a clear advantage?
Thank you in advance for your time and assistance.