+1 to that.
But in general it sounds like BS to me. Any heating
system you buy today is going to be a lot more
efficient than the one it replaces. And that should
mean cooler exhaust temps, not higher ones.
With a high efficiency condensing system, the
exhaust gases are so cool that 1 1/2" or 3" PVC
pipe is used to vent the unit directly outside
without a chimney.
Now it's entirely possible that he could have a
crap chimney that is in such a sorry state that
it won't pass inspection. That would prevent
any new unit, oil or gas from being installed.
Gas runs cooler than oil. In the past gas required a double wall class-B
metal chimney and oil required an insulated class-A chimney. A masonry
chimney could be used if it was lined, water would condense out of the gas
exhaust and damage unlined mortar joints until it leaked through to the
Now gas condensing furnaces/boilers need only a plastic pipe. Don't listen
to the idiot who told you that, ask people who know the real answer, and can
give you solutions.
Most brand new gas condensing furnaces exhaust out thru 4 " plastic pipe
(636 it's called), rated for 65 C, not sure what that is in F. Chimneys
are no longer required for high efficiency furnaces, and to honest, are
they still allowed to sell furnaces under 92 AFUE where you are because
they are not. My gas exhaust pipe just runs along some floor joists and
out the wall for a total 20' run.
These days gas furnace exhausts alot more steam than anything else.
There may be government rebates in your area regarding furnace
replacement. Research them.
Sounds like you got to find some more guys in your area who can give you
Speaking of class B (or Type B) metal chimneys, I am in the middle of trying
to get one figured out. I'll post a new thread about my situation and
I my case, I couldn't change my boiler to a high efficiency direct-vent
system without a huge expense because I have a one-pipe steam radiator
heating system. They don't make high efficiency direct-vent steam boilers
and changing over to a hot water system wouldn't work because I have
one-pipe (not two-pipe) radiators now.
Steam heat. Real boiler.
There is a way to extract additional heat, just like the hot air furnace
works, additional hot air heat extractor. You would need at least one
complete air ducting.
With steam the heat coming out of the chimney is going to be around 210
degrees or higher, if it's boiling.
I hope you will reply back with some additional information regarding what
type of heating system you have now (such as steam, hot water, or hot air --
if steam, one-pipe or two-pipe radiator system), how many BTU's your heater
and hot water heater are, what diameter connector pipes go into your present
chimney, and what type of chimney you have now.
Bruce K. wrote:
So you switch to a high-efficiency gas furnace that vents out the wall
and bypasses the chimney entirely. That's how high-efficiency gas
Before I switched to a high-efficiency furnace, the installer for the
prior gas furnace expressed some doubts about the heat integrity of my
chimney. He installed a liner in it. Problem solved.
There you go - two solutions that let you get what you want.
Two words - BEE ESS.
You can ALWAYS go to a chimney-less condensing gas system that
exhausts through the wall, just above ground level, with a 2 inch pipe
that never gets hot enough to soften, or even be uncomfortably warm if
Most likely not from the heat but from the moisture
Also modern high-efficiency gas furnaces will shove less heat up a chimney
an old, less efficient, oil furnace.
Why not look at a high performance gas furnace that does NOT need a chimney
and has both vent and air intake to the side of the house ?
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