"Larry Levinson" wrote in message
...
we haven't noticed a problem with the dust going from the workshop,
through the furnace, to the rest of the house. apparently, it just
goes from the workshop, to the furnace, AND STAYS THERE. sigh. but
thanks. May be a 6" duct for outside air isn't such a bad idea ..
though, punching that hole in the wall doesn't sound like fun ...

Don't forget that all the combustion air you bring in means that heated air
has to be forced out somewhere else.