I want to enclose my oil furnace with drywall and use the other space as a gym. Can I close off the furnace and add an electric fan from gym to the furnace room?

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    – isherwood
    Commented Feb 22, 2023 at 14:31

2 Answers 2


There are two issues with enclosing any combustion appliance:

  • Heat - Typically there will be specifications of the distance required between the appliance and any walls or other stuff.

  • Oxygen - Unless the appliance has separate input ductwork, there will typically be minimum requirements in terms of the size of the room and/or the amount of open space required to provide sufficient air (but really oxygen) for combustion. Incomplete combustion can be deadly.

I would not rely on a fan to provide air for combustion. If the fan dies but the furnace keeps going you could be in for a rude awakening. Or lack thereof.

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    Note that the distance-to-flammables spec can range from multiple feet with older furnaces to contact with some of the most efficient modern designs. Read your furnace's manual for official specifications.
    – keshlam
    Commented Feb 22, 2023 at 13:37

As long you provide enough air to the furnace you should be fine.

Fan might be risky if it stops operating thus a permanent air flow is preferred.

Since you need access to the furnace you can use louvre doors type as permanent air supply (preferably in metal). They come in steel (you do not need) or aluminum which is much lighter. Installing a smoke alarm with carbon-monoxide sensor is always good idea just in case. There shall be enough space around the furnace to do service from all sides.


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