I noticed an opening in the cold air return duct near the furnace (for improved air flow) in the same room as the water heater. Seeing that the fuel type for the water heater is gas, is this an acceptable and safe situation?
Depends a bit on location of the unit and the duct. I would also need to know the size of the room.
In general I would say that is not a good thing especially if there is a door or something that can close the room off.
This is not acceptable to have a return in the same utility room.
Also like me in the past just call it a water heater.
What type of furnace is it? Do you have a picture of it?
hell lets call it a cold water heater, thats what it is
Unless it utilizes a recirculator, then it would be an “up to hot” Water Heater!
hot water doesn’t need heating