wrote in message
oups.com...
I am finishing my basement of my condo, adding a bathroom and
bedroom. I plan to build a small room around the furnace and the
water heater. What do I need to do to ensure that the burner of the
furnace gets a good supply of fresh air? Since people will be
spending a lot of time in the basement, do I need to run an air supply
line to the outside of the house to prevent a buildup of CO2 or CO?

A high efficiency furnace will solve your problems.
I have seen insulated furnace rooms with large vents to the outside. If you
don't have direct access to the outside you could probably do it with
powered ducts, but I would leave that to a professional.

There are issues with basement bedrooms, as others have said. Consider a
basement den.