Due to the closeness of the buildings in NYC, (row houses you call them
flats I think) apartment buildings and the like, the neighbors might not
like your boiler venting into their window with a side vent arrangement.
That notwithstanding, unfortunately many building codes (and the bureaucrats
that administer them) here are unable to adapt to new technology.

Tony

"Mark Rand" wrote in message
...
On Mon, 2 Jan 2006 01:28:27 -0500, "Tony"
wrote:




Nope, not old data. I was at the last heating symposium at Brookhaven
National Lab Brookhaven Long Island 2005. It's nice to hype 95%, but to
really get over 90% you enter the realm of condensing boilers, which
means a
direct vented system as opposed to a conventional chimmny. Most gas
boilers
installed today are around 78% ~85%. Some gas boilers less than that.
Some
local building codes do not permit direct vented heating systems, NYC for
instance.



Just out of curiosity, what's the matter with condensing boilers and
direct
venting systems in your neck of the woods. I fitted my balanced flue
condensing boiler (stainless primary and aluminium secondary and tertiary
heat
exchangers with entirely copper water path) 8 years ago and have been very
happy with it, although my gas price/Btu is probably a lot more than
yours.



Mark Rand (in the UK)
RTFM