Welcome to the forum. All newbies are invited! Does the 5300 sq. feet represent the conditioned space only or are you including a basement? What are the areas of the first and second floors? What have you done about insulating the old part of the house and the windows? What is your location? FYI - general contractors know very little when it comes to HVAC. Spending money on HVAC is low priority for them. They are going to want to use the cheapest sub contractor for the work. Most people do not realize what they are getting until it is too late. It is good you are asking the questions now. I think the furnace model number is wrong. I can't find anything with that model number. The AC condenser is a Base model. This is builder's grade equipment. Carrier has good equipment as long as you stay away from the low end models. You also need to know the coil model and size and what thermostats you are getting. I would recommend getting 4 inch media filters. Your house is big, but I think 160K BTU of heating and 8 tons of cooling seem over sized even for a 100 year old structure. The first thing you need to ask is how were these sized determined. For a major renovation you should get a Manual J calculation. This is a detailed heating and cooling load calculation. If the HVAC contractor does not want to do this, then consider getting another HVAC contractor. Once the required sized are determined, then you can get to equipment selection and prices. Is the new duct work a separate quote? Are both furnaces located in the basement? The a lots of details to iron out. Take it a step at a time and start talking to your contractor.

Gotcha. I will pass this along to the builder for him to have hvac guy do. I spoke to hvac guy about the $400 overrun vs the over-the-phone/options fax estimate (turns out it is not $1k -- $600 of that is the builder's problem for the 13 SEER base upgrade). He said that $200 of that came from needing to add 120v wiring to the power humidifier since it does not run off the furnace fan. We didn't specifically get to the other $200 as he stated that FILCAB was $450, and EZXCAB was $275. FILCAB is what was in the quote. So after a $40 MERV10 filter for EZXCAB we're now at $10 less than the upgraded quote. Interesting, especially since he previously said FILCAB was $225 -- and I had to set him straight that FILCAB could only take MERV8 filters from what I understand. I'll make sure the builder also gets a competing quote. And I am getting the complete model number of the coil in writing, of course.

Okay... I received updated AHRI reference numbers (and copies of the certificates) from the Bryant dealer for both the 60K and 80K furnace options. One thing I am concerned about is the clearance for the stack of equipment in the basement utility room. There is only a clearance of 63 inches to the bottom of the main supply duct. The Lennox dealer mentioned this, and the Bryant dealer took note of it as well, but here are the options the Bryant dealer has presented me with: 60K Unit AHRI # 4891891: Condenser: 187BNA036 Coil: CNPVP3717ATA Furnace: 355CAV04260 80K Unit AHRI #4891910 Condenser: 187BNA038 (same) Coil: CNPVP4821ATA Furnace: 355CAV060080 The coil for the 60K unit is 5 inches taller than the coil for the 80K setup. The total height of the stack (including a 2 inch base) for the 60K unit would be over 69 inches - that doesn't seem like it would fit. The 80K setup that they have specified still has a 64 inch height, which would mean the coil sticks part way into the supply duct - is this a significant problem? I have found the Bryant 2010-2011 product handbook so that is helping me to put together what I think is the ideal system. If I understand it, ideally I need for my use a 3 ton condenser, a coil that can handle at least 3 tons of cooling, a furnace that can provide at least 3 tons of cooling airflow (it looks like Bryant has two options here - 3.5 tons of airflow (042 series) or 5 tons (060 series). I need the combination to be less than 61 inches tall (to allow for the 2 inch base underneath and I want it to be eligible for the cooling tax credit (which I think means minimum 16 SEER/13 EER rating). I THINK I should be able to put that together, but I need to cross reference the overall design. Just a quick question - the coil and cooling airflow capacity can be oversized without adversely affecting things, correct? When we talk about correct sizing we are referring to the condenser and the furnace output right? Thanks again for any input. Ted

Mike_Home - Thank you for the answers and advice. Here are some responses and follow-up questions. 1. SEER/EER - your answer is what I had been slowly understanding that these numbers are what drive the efficiency numbers. Rough calculations comparing my older 10 SEER unit to a 14 and 16 SEER unit plus using 1 year of energy bills, show a potential electricity improvement of $184/year for the 14 and $238.31 for the 16. Of course this is all dependent on a quality install as well as proper ducts, etc. as you've outlined in other points. 2. Payback will be uncertain as I was relocated for work. Not sure how long we'll be here and at this point, the energy savings per year is still important. 3. Understood. Before my research, I didn't realize that the furnace played such an important role in airflow. 4. My zoning explanation might have been poorly stated. The gist of what was mentioned, was that based on proper zoning, the more efficient airflow distribution within the home may allow for a 4 ton condenser. The condenser potentially wouldn't have to push air through all of the ducts at the same rate. Does that logic track with your experience? 5. Appreciate thermostat advice and handling all the features, etc. 6. The annual maintenance contract was from the contractor providing the detailed Goodman quotes. Participating in the yearly maintenance contract covers 100% of repair costs (Contractor backed, not OEM), includes a 10 year replacement warranty, and there are no dispatch or service fees for service calls. The replacement warranty is the full replacement of the failed unit rather than just repairing under the 10 year labor warranty with Goodman. If I don't do the yearly maintenance contract, there is no replacement warranty. Ever heard of this? The contractor (Goodman quotes) may have mentioned "calculations" at one point but I don't remember hearing about them doing a manual "J" load calc. As far as I can tell, Title 24 doesn't require the J calc. It does require a duct leak test performed by a certified 3rd party HERS testing company. This is required on ALL HVAC projects in CA. Rebates are only available as part of CA's Home Upgrade Program. This program has required testing and upgrades on items like ducts, whole home envelope, attic insulation, etc. I will go back to two of the contractors and ask them about performing the calculation. I am looking to replace the whole system at this point to make sure the equipment is compatible and most efficient. Goodman is making me increasingly nervous, especially with the Class Action lawsuit that was just set back last week based on a judge's ruling... As for the use of a different coil with the Goodman equipment, it seems to be very common with Goodman quotes (based on board postings like this). I think there is a relationship or commercial connection between Goodman and Aspen to drive the high use with Goodman systems. I don't know the true specs on the Ruud equipment, I was guessing a bit; I will ask for the models, etc. Thanks again!