cost of converting Oil furnace to gas?

[Mike Kooser Sr]

Has anyone did this in the past if so how was your experience? I have a rental 3br row home that currently has oil heating. Im looking into changing it to central air but I just read about converting it to gas. The water heater right next to it is already gas. The oil furnace is only about 6 years old and is in good condition.

Any advice would appreciative.