Thanks so much for your responses.

Im going with contractor 1, the only one who suggested four tons and also the best price.

Ill let you know how it goes.

It would be very interesting to figure out why the estimates ranged from 47k to 88k and even 144k btu.

Is this fraud? Incompetence? The estimating tools are horribly inaccurate? People (other than Dana) don't know how to turn utility bills into load estimates?

I'm in the long drawn out process of doing a 2500 sq ft home and had quotes from 8 tons to 2 tons -

from prices in the range of $75,500 ( 6 ton quote ) to $32,000 ( 2 ton quote )

I've had a similar experience - contractors in my area are not willing to give BIN reports - even telling me that they no longer wanted to bid the job when asked for such information.

Unwillingness to share data is consistent with fraud.

Even in a new house, one could bring in portable heaters for a night and get far more accurate results than that.

Is this fraud? Incompetence?

Let's call it some combination of those with an (un)healthy dose of laziness thrown in. You just have to keep looking for the honest and competent contractors. Get them via word of mouth from other people in the trades you know and trust. Don't get them from advertising as that is where the bad ones spend much of their ill-gotten gains; trolling for new prospects. The quality subcontractors are kept too busy working to play games with their yellow pages ads.

Never attribute to malice what can be ascribed to incompetence.

Somewhere between 9 out of 10 and 99 out of 100 HVAC contractors haven't the foggiest notion what is a BIN report is, other than the vague notion that it may have something to do with the number of copper and plumbing fittings present in tubs on a set of shelves in their service truck or back in the shop.

Had to Google that one...Got a few hits for Bin Laden...

Is this a good link to explain it?
http://www.interenergysoftware.com/binM/humissue.htm

?

That one looks to be overkill