This past Friday (7/15/05), the installation of my Carrier Infinity 96 Gas Furnace and Infinity 18 Air Conditioner was completed. This was my first HVAC purchase of my lifetime. I am having buyer’s remorse and believe I should have put more time into researching my options BEFORE and not after my purchase (Like I have been since the installation). I live in Western PA and my 20-year-old Bryant furnace (90K BTU?) had needed too many repairs the last few years, so I decided to replace it. My Bryant A/C (2.5 ton) seemed to work fine, but I felt it would be best to replace it since it was also 20 years old.

I only obtained two quotes: a lennox dealer quoted the 90K BTU G43 and Merit Series 10 ACC (3 ton). The Carrier dealer quoted me the Infinity System. I was too DUMB to ask the Carrier dealer about BTUs and tons. After spending several hours on this site and others, I think I understand (a little bit) about some of this HVAC terminology.

I decided to go with the Carrier quote due to a recommendation from a friend/builder and the dealer’s reputation for quality work, despite a $2000 difference. Also, the sales rep sold me on the high efficiency, two-stage, variable speed hoopla! (My old Bryant cycled off and on every 60 seconds in winter). After checking my model numbers on the Carrier website, I see that I was sold the 58MVP060-14 (60K BTU) and the 38TDB024 (2 ton).

I am unhappy with the cooling performance of the system. On Friday at 4:00 pm the installation was completed. At that time, the indoor temp was 87 (outdoor - 90). The temp only dropped one degree per hour and by 9:00 pm; it was still 83 on my first floor, 88 on the second floor (Cape Cod style house – my second floor never gets below 80). By 3:00 am, it finally dropped to 74. I have set the target temp to 72, just as an experiment. THE UNIT CANNOT GET THE TEMP BELOW 74, EVEN ON HIGH FAN SPEED. Today (Sunday) with the fan speed set to high, the temp was 77 at noon, stayed at 76 until 7:00 pm, and then dropped to 75 at 8:00 pm (outdoor was 93 at noon, 75 at 8:00 pm). Last night I took the following readings: LR supply temp – 55, BR supply – 60, 2nd Flr Bath supply – 64, LR return – 70.

While I am not an Eskimo and would rarely have my target temp at 72, my concern is the time it takes to reach the target temp and my inability to get my second floor below 80. The airflow coming out of the registers seems too weak. While my old Bryant sounded like a jet engine, that sucker blasted cold air and cooled the downstairs very fast! Even the installers said the register airflow seemed weak, but said the system was running perfect, based on the readouts from their equipment and the thermostat. They did however; remind me that my basement ductwork was abnormally large (main supply is 31” x 8” extending approximately 13 feet before branching off into smaller runs). I assume they will try and tell me my ductwork is the problem.

My bottom line question is: Is this system undersized for my home (1800 SF Cape Cod w/ unfinished basement) and ductwork issues? It seems to me that the blower isn’t pushing enough air to cool properly. Do I need a larger A/C, furnace or both? The lennox dealer quoted larger units and the ones pulled out of my house were larger units. I don’t know how the Carrier salesman calculated my system needs; I didn’t even know what manual J was until I investigated this site. He took rough measurements of the outside of the house and sent me the estimate in the mail.

I spoke to the Carrier salesman today and expressed my concern. They are sending a technician out to check my system early this week. Since I am just an uneducated HVAC consumer, what advice can anyone give me before I meet with the technician?

Sorry for the extra long post, but I wanted to provide enough data to describe my situation.