I am at the punch list of my renovation. While generally happy with the work the sub on the HVAC was clueless and couldnt get machine to work. A new sub came into finish and fixed it by turning down the heat on the furnace. The apt is 2200 sq ft. I have a 5 ton unit with heat/cool. There are 2 zones. In zone 1 the first 10 ft of duct are 20x8 then 32ft at 18x8( there are 2 turns). Zone 2 has 10 ft of duct at 20x8 and 34ft at 18x8 again with 2 turns. All ducts are insulated on the inside( 1" on alll sides) so it reduces interior duct size to 18x6 and 16x6 respectively.

While I believe it will continue to work as is the question is how inefficient is the current set up? Would the increased ConEd bill warrent a change in ducts? What are your thoughts on the cost tradeoff?

There are so many elements to a properly functioning HVAC unit, there is no way anyone on here can tell you what to do without an on site assessment.

I can tell you though, even with 15 foot ceilings, 5 ton is too much for 2200 square feet. It is the biggest mistake everyone makes, going too high on the tonnage for cooling.
If your annoyed now with the heat, wait 'til the summer when you cant understand why it's cool but so humid.

It's a delicate balance between environment, size of unit, and SEER rating. Not much one can do for installing a wrong system though.

Otherwise, playing with baffles or blocking some vents can alleviate most duct problems. And having 2 zones is the biggest leap one can make in efficiency.

truthskr10, aren't there many factors that determine cooling capacity requirements beyond square footage? Obviously a top-floor loft with enormous south-facing windows will require more BTUs than a north-facing pre-war with thick walls on a low floor, even if they're both x square feet.

Regardless, I agree with you that answering this question on a message board is impossible, and this thread further reinforces my belief that most HVAC "contractors" in this city are crooks.

flarf
Absolutely, that falls into "environment" in my statement "It's a delicate balance between environment, size of unit, and SEER rating"
But if the apt has 15 foot ceilings and 25 feet of south facing windows, you'd still be better off with a 4 ton.
Though if both zones are on the same floor and it's not a duplex, one could probably get creative.

Thanks truthskr10 and flarf! Do either of you recommend someone qualified, who would, for a fee come and assess my situation?

Im still looking for a good HVAC person myself, as flarf says, "most HVAC contractors in this city are crooks" I would like to add, or don't really know their ass from their elbow.

Ive experienced both and have nobody to recommend on my good name. Sorry.

SE forums have been a bit slow these days, give a bit of time for others who may have a reco.

I'm using Arista now but the work isn't over yet, so take it with a grain of salt. They did come highly recommended by my architect and the general contractors I spoke with.

2 non recos

1)Airtronics Air Conditioning; charged me an arm and a leg for a maintenance look over and didnt demonstrate a real command of knowledge. (certainly not for the price)
2)MetroAirCool; Unreliable. Stay away.

Thanks guys. Anyone else out there in the Street Easy universe recommend and HVAC contractors??

Anyone?

Airflow Mechanical gets a mention in this recent thread: http://streeteasy.com/nyc/talk/discussion/32535-installing-central-air-in-classic-6-prewar

thanks flarf!!