I have a 16 year old York HVAC system that I am going to replace. It is the original system installed when the house was built back in 1996. It appears the evaporator coil drain pan is leaking plus there is a freon leak causing me to have the A/C system charged at the beginning of each summer for the past 4 years. 4lbs. of freon were added this month. The water puddling up at the bottom of the furnace reduced greatly after freon was added as the coil may have been icing up. Now there are trace amount of water around the furnace. The condensation line has been checked and it is open and draining. I figure replacing just the A/C system after water has been dripping on the 16 year old furnace is probably not smart. Right?
The current upflow gas furnace is 80% - 100,000 btu input and 80,000 output with a 1/2hp blower motor which I have read is a 4 ton blower. External A/C condenser is a 3.5 unit. Evaporator coil is rated for 4 tons. This system serves the 1st floor and basement of the house. 1st floor is about 1735sq. ft and 9ft. ceilings and basement is 1247sq. ft. with 7ft ceilings. Combined it is about 3000 sq ft. without factoring in ceiling height. I have a separate attic HVAC system for the 2nd floor - 1136sq. ft. which I already replaced the coil drain pan 3 years ago.
I have had 4 different companies, including my gas company give me estimates for a replacement system. Since I plan to be here at most another 5 years, they all are steering me towards another 80% furnace with a 13 seer A/C due to cost recovery time. When pushed, they will discuss higher efficiency systems but venting to the outside seems to be an issue as the most accessible area to install a new intake & exhaust vent outside is located next to a corner and 24" from a window and will only be 12" above ground. It will have to be located right next to my sump discharge line. It is possible, but very infrequent that we receive more than 12" of snow being in Maryland, near Washington, DC. Mind you only the gas company contractor pointed this out and said he will not install anything higher than a 80% due to intake and exhaust venting. He also pointed out that going to a high efficiency furnace will require sleeving the existing flue to reduce it's size so that the existing gas water heater continues to vent correctly. I understand the issues with venting the furnace but have not found enough documentation to determine if it would be code compliant or not. As for the orphaned water heater, I have done some reading but wasn't able to determine if I need to sleeve the flue. Currently both the furnace and the water heater vent to a flue that is roughly 6.75" in diameter, up from the basement, thru the 1st and 2nd floors to the unconditioned attic and out thru the roof. I need help understanding the 7x rule.
None of the companies has conducted a Manual J and when asked, they tell me that the existing system was correctly sized by engineers prior to the building of my house and is correct based on square footage. Again, the 1st floor has 9ft ceilings and the family room 15ft cathedral ceilings. The basement was finished 10 years ago but no area was added to the house. Only some additional ductwork. None have measured the house or asked me for dimensions. From reading tips on this and other forums, a Manual J should be done, right? I can tell you that the family room built on a slab with 15ft cathedral ceilings is 4-6 degree colder in the winter than the rest of 1st floor and I have various drafts that I can not determine their source.
I like the idea of a high efficiency furnace with a multiple or variable speed blower such as the one found in the below Goodman. The price between a 80% and a 90-95% furnace seems little compared to energy cost saving. I am assuming I am going to save money by going to a 13 seer A/C vs. my existing 8-10 seer A/C so...
Systems under consideration:
Goodman - GMH950904CX furnace, GSX130421 A/C, CAPF3642C6 Coil
Payne - PG9MAB048100 Furnace, PA13NA048 A/C and CNPVP4821ATA
Carrier Systems with a rebate until 6/30/12.
If I have to drop to a 80%, the Payne units have gotten very good reviews from what I have read.
2 out of 4 companies are quoting Carrier. The gas company contractor explained the reason they sell Carrier is because it is the brand most commonly stocked by local distributors. One quoted Payne saying that it is the same as the lower level Carrier, just a different color and cheaper. The 4th quoted Fridgidaire. None really like Goodman which I had recently had installed in a rental house by a contractor who won't service the area my house is in.
Sorry for the length but I figure the more info I provide the more helpful info I'll get.
Pictures @: http://s210.photobucket.com/albums/b...IMG_0001-1.jpg