Use a when the h is pronounced as a hotel (ho-tel).
- I stayed in a hotel for three nights.
Use an when the h is silent as in an hour (our).
- He missed his train and was an hour late.
The rule for using either a or an before adjectives + nouns is the same.
Use a when the h is pronounced as in healthy (hel-thee).
- I am glad to hear that she is a healthy baby.
Use an when the h is silent as in honourable (on-er-rable).
- He is an honourable gentleman.
