That's a good question. The word "home" can be a noun, adverb, adjective, or verb depending on context. In your example, "home" is an adverb so there is no need for "to" or "the".

When referring to one's own home, one says "I am going home." If one is going to work, "I am going to my office." or "I am going to the office". There isn't a good reason "why" one goes home instead of going to home. "Going home" is a very special case -- an exception to the rule. In almost all other cases, it would be correct to say "I am going to the [house/park/store]" When referring to another person's home (Michael for example), one says "I am going to Michael's house." or "I am going to the home of Michael."

Don't forget the article before 'office'. 'I am going to the/my office'