Looking on the internet deeply has found these results:

I'm in home is the most popular phrase on the web.

I'm at home 1142,000 results on the web	I'm in home 15,870,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
I will collapse, so lets make this moment last. I am alone, no not because I'm lost, because I'm found. And I like the way it sounds when I'm at home. Don't say ... Apr 15, 2011 ... "I'm at home" is what you say when someone asks you on your cell phone or IM where you are locate. "Where are you?" "I'm at home right now. I'm at home. With a time reference they can be used in the same way in current speech. " I'm home this evening if you want to call me." "I'm at home this evening ... "I'm at home" is not usually used to explain that you've just gotten home, but rather as a way of differentiating between home and other places you might be.	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

I'm at home

1142,000 results on the web

I'm in home

15,870,000 results on the web

More popular!

I will collapse, so lets make this moment last. I am alone, no not because I'm lost, because I'm found. And I like the way it sounds when I'm at home. Don't say ...
Apr 15, 2011 ... "I'm at home" is what you say when someone asks you on your cell phone or IM where you are locate. "Where are you?" "I'm at home right now.
I'm at home. With a time reference they can be used in the same way in current speech. " I'm home this evening if you want to call me." "I'm at home this evening ...
"I'm at home" is not usually used to explain that you've just gotten home, but rather as a way of differentiating between home and other places you might be.

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.