Can this be applied on a window in front of a house? Is this like a one way mirror that would provide privacy from outside?

This particular film is opaque, not one way. You would not be able to see through it from either direction. If you wanted a silver exterior and a grey interior, this is the film you need: https://www.decorativefilm.com/sx-sg09-silver-grey-one-way Just one reminder: it is not as effective at night if it's bright inside and dark out.