Find the right guy and you won't have to come on here asking so many questions.

If you had myself out to your house, your pose wouldn't be necessary. Keep looking.

When you start calling others ask them about the "ACCA quality installation checklist". If they haven't heard of it then move on.

*post

If I were in your shoes, I would be looking for an unbiased energy rater and a local program to help pay their fee. They can identify the low-hanging fruit for energy savings and help you find the best solution to your HVAC problems.

For future expansion, consider heat pump mini-splits. Maybe even for now.

Here are some answers:

-- Is it possible to calculate air flow in to determine better if that is a potential factor?
A good contractor will measure your ducts and calculate the air flow it can support.

-- Is this Carrier system a good fit (notwithstanding no Manual J calculation)?
The Carrier Infinity furnace is very good. I recommend moving up to the Comfort AC rather than the base model. You need to find a contractor who will do a Manual J calculation. I think 2 1/2 tons is oversized, but no one can tell without the proper calculation.

-- Any comments on the price?
The price seems on the high side, but it is not fair to critize it without seeing the installation.

-- Any ideas for upgradeable systems?
Do you have an idea how you will expand your house? You may be able to install a system which could cover the current and future needs. If you are planning a major expansion, then you will need to put in a second system. Discuss your expansion plans with the contractor for possible ideas.

A heat pump is a viable option. Your electricity and gas rates will determine how much savings you could achieve with the heat pump versus the furnace.

An expandable option that I used was a 2 stage zoned Infinity heat pump. It was sized to my final house size. Oversized initally, at least it could run in low stage and not act oversized. This solution is not ideal but may be a possibility for you.

So no one has mentioned it, R19 in the attic is pretty bad for DC and easy enough to fix. If you have blown insulation, it is usually recommended to remove, air seal, then replace with more. I guess even if you don't have blown insulation, you could the same thing.

Thanks for your responses.

All three contractors have visited and I have two quotes. The first in the original post. The second recommends Amana 16 Seer 2 ton, 2 stage compressor with an oversized 3 ton coil for cooling and Amana 80,000 BTU/80%, 2 stage, variable speed furnace. Nothing about changing return ducts.

The third firm suggested zoning the system split first floor and upstairs with separate thermostats to control a pnuematic damper in the attic. Do this first and then see if the cooling and heating systems needed to be upgraded. He was their ducting expert and he thought it would be better if the returns were larger, but he thought too that the zoning would solve the problem for the majority of the time. I have yet to get their quote so this detail may change.

I am not sure that I have found the right contractor yet. The lack of Manual J calculation bothers me. I am concerned too that there has been no attempt to better quantify the flow issue. I have asked pointed questions about this and been given answers along the lines of " xx years experience" or "not needed for replacement of existing systems". These are, in theory, the top rated HVAC firms in the DC Metro area on Angie's List.

So how do I find a firm that, as seaton puts it, would make it unnecessary for me to post so many questions?

Returning to the point of my post. I think it would be unwise in my situation to size for the future and so am concentrating on getting the house right as it is. I will not be worrying about the basement either.

I found a link to a blog that talks ducts: Fred Weldin (that can be googled) - I learnt some things from his site last night.

Does anyone have experience or opinions about the Amana furnaces and cooling systems? I was told that they have lifetime warranties on key parts that distinguishes them from all the others.

Second, does putting in a coil that is 3 tons make sense for a 2 ton condensing system?

I need to fix my attic insulation and appreciate the nudge from david cary!

Any other thoughts or advice welcome.

MoT

I know nothing about HVAC systems other than I am looking for one.....but all the 5 contractors that have quoted me, say to stay away from Amana, so I'm passing that along. I have had Lennox quoted(very high) Carrier, Bryant(a division of carrier), Goodman(what I have now),and another Carrier dealer. I like the Carrier name since they seem to have the best units out there right now. The one who quoted Bryant says they just have different tags on the same equipment, that it is exactly the same machine. Who knows?

I've been working with MOT to troubleshoot his duct system.

It turns out the 2001 work leaks like a sieve, has a high resistance fitting arrangement at the supply plenum, is underinsulated (overcompressed R4.2 wrap and R4.2 flex), the flex branches are 'snaked', and two 10" flexes for the two ton return are borderline at best.

He's currently looking for a sheet metal contractor to make it right.

Here is a link that might be useful: Weldin Engineering Co.

While he's in his attic, he needs to go from R19 to R40.