Cold draft in rooms because of cold air return vents
I noticed that there is a cold draft in my living room (1rst floor) and bedrooms (2nd floor) from the cold air return vents (located on the inside of an outerwall). Is there a way to prevent this draft from entering these rooms?
My house is a two story (not including attic and basement), all brick house that was built in 1937. It has a forced-air gas heating system and also a firewood insert. When the gas heat is running, there is no draft probably since the air is being sucked into the furnace. When the firewood insert is on, the draft is present.
The temperature of the air coming from the cold air return vent is about 55 degrees. The outside temperature is currently 23 degrees farenheit.
Is there a way to prevent this from draft from occuring when the gas heat is not running, which should be the majority of the time? (Perhaps some type of sponge material?)