Bats irked me today.
Well not so much the bats, or the fact that in the last 24 hours I've caught two of them flying around in circles in one room or another of the house, but the fact that I can't seem to find where they're coming in. Chimney is ruled out- that's sealed off after I had a minor fire in December, and I don't see how they can wiggle through the grates over the vents, unless a bat can squeeze through a hole that's only about a quarter inch wide. They certainly aren't getting into the house by any obvious means.
Be very careful with bats, it can be a serious thing. They carry critters with them and disease in their excrement. And bats are like roaches, if you see 2 you may have 100s.
A few years ago friends of ours started itching and it was determined that they had bed bugs. They were into every carpet, bed, couch etc in their house. So in the course of exterminating (and throwing out all their carpet and much of their furniture), the exterminator discovered that they had bats in a sealed off area of their attic. The bats hadn't got into their house, but their bugs etc had. Upon opening up that area, there were literally 100s of bats and the whole place had a liberal coating of bat poop, which is where the bugs breed and live. The clean up was bio-hazard and required men in white suits. All the attic insulation had to be removed as well as their bedroom ceiling since the sheet rock was saturated from above. Several thousand dollars spent.
They had never even thought they had bats. Living adjacent to woods they'd see them flying around but never saw them get near the house. The space they got in was minuscule. They found a tiny hole between the siding and soffit. .It all traced back to a neighbor who had a bat house on a tall pole at the back of their property. It fell down during a storm and the bats found a new home... in my friends attic.
So be careful. It may be worth getting an exterminator experience in bats to look around.