Allowed in vs. to be allowed in

Hello.

#1. In addition, they can regulate your home’s temperature by controlling the amount of sunlight “allowed in.”

#2. In addition, they can regulate your home’s temperature by controlling the amount of sunlight “to be allowed in.”

Of course #1 works better and it sounds correct and natural.

However, I don’t know why #2 sounds so awkward and bad. It sounds so weird.

There is a difference between “allowed in” and “to be allowed in”.

My assumption is that “to infinitive” in itself is more likely to agree with the future. (I am not sure whether my hunch is on the right page. My gut feeling says “no.. #2 doesn’t sound right…”)

A. #1 and #2 are grammatically correct?

B. Does #2 sound natural to you?

C. Can #1 and #2 be interchangeable?

I’d very much like to hear your opinions. (If there are some explanations including linguistic and lexical perspectives, I might fall in love with you. ??)

I really appreciate your help.