Thanks for the quick responses! The existing furnace is an oil-fired York, 125 KBTU, which is at least 30 years old. I have been told it's horribly inefficient, but I don't know the number. The AC condenser is 3 tons and 25 years old (also not efficient). The house should probably have 2 zones (especially to deal with better cooling the second floor in the heat of summer), but I have been told that's not possible (at least not for a reasonable price). Otherwise, there are no noticeable issues with the current system, other than those endemic to scorched air heat. Each room has at least one supply vent and one return. The basement is below grade and is used as living area. There are two supply vents and one return in the basement area. There is no insulation between floors, but the basement walls are insulated (R-7.5). Beefing up the attic insulation is on the near-term to do list. The house currently does not have a humidifier, and while no one is suffering nose bleeds, the air is dry. So, I thought a humidifier would be helpful. I would definitely like to tighten the house (and new windows may be on the radar in the near future), but given that it is an older home, I think there is only so much that can be done. The Carrier dealer said the furnace would be no more than 100 KBTU, with the final determination after the house is measured and a load calculation performed. Both companies will also do a whole house energy audit prior to commencing work. So I would assume (and hope) the Lennox dealer will modify his numbers accordingly after the load calculation and energy audit. Our natural gas marginal price/therm is $0.83 Our electricity marginal price/kWh is $0.22 for on peak, and $0.07 for off peak. With regard to the Carrier condenser, what makes the 24ANB6 superior to the 24ACC6? I know a lot of people on this forum prefer Carrier over Lennox. All else equal, I have no problem going with Carrier (I know the Infinity controls are fantastic), but there is a $1,500 price difference... Thanks again for your help.

2 tons to 3 tons - that's significant. Did this company say that they plan to do a load calculation to ensure that this isn't oversized, which will impact humidity control in the summertime. Additionally, 3 tons will require additional duct capacity compared to the previous 2 ton system (which may have had marginal duct work to begin with, don't know how big your current duct system is but sadly not uncommon). Variable speed air handlers on undersized duct systems can be problematic as far as noise / electricity consumptions. The ductwork definitely needs to be sized appropriately to handle an extra ton of capacity. These are some important things to consider and address with the dealer. The scope of work seems reasonable overall. Some things I'll point out that I don't see in this proposal compared to the previous: AprilAire 600 Humidifier Honeywell F100 Air Cleaner New ductwork for return and supply in utility room (I'm actually not sure how involved the modifications will need to be based on this line item; the new proposal does specify a new return box and trunk however.) Load Calculation Versa Grip Duct Sealant Surge Protector Nitrogen Purge 10 years warranty on parts, labor and compressor If the air cleaner and humidifier aren't important items to you (I enjoy the added comfort a humidifier provides in the wintertime even though they do require seasonal maintenance that can typically be done by the homeowner, but I would at least want the air cleaner for the equipment's sake). I feel there is a definitive difference in complete work scope here. Perhaps these two options could be removed from the other estimate to make the two proposals more comparable. The Bryant 225BNA model is a bit nicer unit. Thanks for giving us an update. I know all the details can get confusing. I'm not here to convince you to go in one direction over the other, but I'm happy to answer any further questions you have and add comments as appropriate. I look forward to seeing any further advice other members provide. Best of luck! This post was edited by ryanhughes on Fri, May 16, 14 at 15:18

I should also add that here in WA we don't use the AC a whole lot, we'll be more concerned with heating costs. The SEER ratings just apply to AC right? so maybe I should be more concerned with HSPF.. XP14: 9.50 HSPF XP17: 9.50 HSPF XP21: 9.70 HSPF XP25: 10.20 HSPF which tells me, my heating costs will be pretty much the same no matter which unit I go with, right? So if I pair up the XP14 a less-expensive air handler such as a CBX32M, will my heating costs be pretty close to even the high end XP25 & CBX32MV combo?

Thanks again, neo. Yeah, that is odd about the SEER rating dropping. Looking at Contractor #2, for instance. Q1 and Q2 are the same, except Q1 has a 21 SEER condensing unit and Q2 has a 17 SEER. Why would cooling capacity go UP with the 17 SEER? Same coil, same blower, different condensing unit. #1 21SEER condenser 96.6% furnace Coil AHRI: Cooling Capacity 57000 BTuh EER Rating: 12.20 SEER: 15.5 #2 17SEER 96.6 Furnace Coil AHRI Cooling Capacity 57500Btuh EER 12.3 SEER: 15.5 Then Contractor 1, Q2 has the same 17 SEER condensing unit, but with an 80% furnace. Also, this quote has a slightly different coil number, 6124 instead of 6024. See here that the SEER goes up to 16.5, and cooling capacity increases as well. AHRI Cooling Capacity 59500Btuh EER 13.2 SEER 16.5 --- I'm not trying to hit every rebate I can. It's just frustrating that some are just barely out of reach with what seem to be pretty efficient systems. You really have to go all out to get them.