1. Folk saying: bats were called rat immortals in ancient times, and bats were regarded as mascots among the people. "Bat" and "Fu" are homophonic. So bats have the meaning of "blessing", and then bats at home are homophonic like "auspicious", which means good luck. If a bat is killed, it may be regarded as an unlucky sign.
2. Geomantic omen: When bats enter their homes, they have the meaning of "blessings fall from the sky". From the perspective of geomantic omen, "blessings fall from the sky". Therefore, it is considered a good sign that bats fly into their homes. If the bat is killed, it may affect the family's fortune.
3. Modern saying: From the perspective of modern science, bats may have entered the house by mistake because they preyed on insects. Bats rely on ultrasound to tell their direction. They don't fly home for no reason. So bats fly into your house, which means there are insects in your room that attract bats.
In a word, no matter according to the interpretation of any culture or belief, bats entering the home are regarded as a symbol of good luck. However, it should be noted that if bats may be frightened and fly around during the flight, they may even bump into windows or walls, so people are advised not to disturb bats' flight easily. At the same time, if bats have died, there is no need to worry too much about the signs they bring, because these claims have no scientific basis.