Makeup air

Yesterday I had a home with two fireplaces, main floor and basement. In the basement was the gas water heater and furnace, along with a fresh air intake duct.

Buyer asked if the fireplace needed it’s own fresh air intake. Isn’t the one in the utility room enough?

What type of fireplace do you have in the basement? Wood burning, vented gas logs or unvented?

Wood burning.

In a short answer, yes. The fireplace may likely cause back drafting at the appliances when it is lit.
Here’s a nice document for reference.

The short answer is probably, yes utility combustion or fresh air is enough. (no additional FA needed provided a window is opened when Fireplace is used)

Old style wood burning fireplace do take lots of air when they have a fire, which is best provided by opening a window in the same room as the fireplace. Given that the fireplace is hardly used in most cases, adding another fresh air intake is probably unnecesary. A conventional wood burning fireplace typically blows more furnace heated air up the chimney than it ever puts back in the house. An open fireplace with fancy mantle placed on an outside wall is an architectural feature but not a useful heating appliance.

A fresh air fireplace is a wood burning fireplace that gets its combustion air from outside. They can be recognized by glass doors that can be easily opened and closed to add wood to the fireplace. There will also be a vent on the outside to take in air.

People normally only use wood burning fireplaces occasionally, they are usually poorly placed for heating the house, wood is expensive, and or labor intensive to burn, wood burning fireplaces cannot be left alone, which also means they will seldom be used.

Gas fireplaces can be good space heaters, new ones are typically direct vent, the firebox is covered with a glass window that cannot be opened. These typically use outside air for combustion, are about the same BTU as gas water heater. They have automatic controls and don’t need to be tended.

Old style gas fireplaces might use inside air, but not a lot of it. Old style gas fireplaces may not have any controls. The flue has a 3 or inch diameter, and they may not have any doors or even a screen. They are not safe (like a 1955 car).

Gas log lighters can be recognized by the large flue or manufactured chimney (8" diameter) rated for solid fuel in the fireplace.