I have a house that there are 3 - 5" metal vents coming out the side of the house. The middle one is exhausting heat from the furnace. The other 2 I do not know what they are for (bringing air into the furnace??) There are no covers on these vents. They are located under a deck the underside of which was covered and I had pulled over the cover and its the first time I had seen these.
I am worried about bugs..etc getting into house because the metal comes to edge of the house siding but there are small gaps.
Should I cover holes with some type of vent like those used for dryers?