I am in the process of framing around my furnace (gas, forced hot air) and water heater. The two units sit diagonally across from eachother in an area of about 5 feet by 6 fit. I intend to box in this area fairly tight with a large door on one side large enough to be able to remove/replace each of the units. Am I allowing for enough air for the two units? I also intend to include a couple of air vents on the surrounding wall and a vent on the door. Thanks in advance!

 

First, make sure you find your furnace's installation instructions. It will give you minimum allowable clearances on the back, sides and front. Building code requires at least 36" working clearance in front of each appliance (with the door closed), no matter what the manufacturer requires.

Put in a 36" door so you can get the new furnace in some day.

Most areas are going to require you have at least two 6" round ducts (one near the floor and one near the ceiling) run horizontally into this room to provide fresh outside air. Some areas will allow other venting methods, but you'll have to check with your building department. Skim on this important detail and you'll put the health and safety of your family at serious risk. The furnace installation instructions will also discuss the requirement for fresh air -- a couple of little vents probably won't do it. The water heater (if gas) will increase this requirement.