What is the right indefinite article to use is it ‘An hour’ or ‘A hour?’

‘An’ and ‘A’ are indefinite articles different forms, we use “a” with words that begin with consonant letters while an is used before words that start with vowel letters like “A, E, I, O, U,” however use of both of these articles also incline towards the pronunciation of words for examples Honor and honest are two words that start with a consonant but when we enunciate these words H is always silent and end when we enunciate these words we usually say “ONOR” & “ONEST” same like this we silent “H” in “hour” too which is why we use an.