On May 8, 11:14 am, "Ray" wrote:
We live in a six-unit coop apartment building with an oil-fired boiler which
supplies radiator heat throughout the building.

In STL, or Manhattan?

We installed a new boiler in 2006 at a cost of $28,000. At the time we
considered switching from oil to gas, but were told that we likely would
have to run new gas supply lines from the street to the building, and this
could cost as much as $20,000.

Well, I wouldn't ask that guy again.

How far is the street?

So we opted to continue with oil.

Leaving aside the cost of installing new gas-supply lines, can anyone give
me a ballpark figure on how much it would cost to switch the new furnace
from oil to gas?

WAG... as much as a new gas furnace of similar output. Or, you could
check one of the auction sites, if you're of that persuasion. The
market is flooded with everything from a-z, mostly commercial and
industrial grade stuff as smaller businesses are giving up and larger
ones continue to downsize.

Or possibly even have a dual supply system so that we could
switch to gas or oil depending upon the costs at a given time?

Or availability. I like the idea. Here, I don't have that kind of
space.

In MT though, I use (free) wood with propane backup. I wonder how
long it might be before more oil users start to consider wood...
Damn!
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- gpsman