Where is heaven?

Andrew used to pray really great for us. Lately, though, he has been less interested in staying still and saying the prayer. Here's how it went the other night:

Andrew: Why do we have to pray every time at night?
Me: Because we need to tell Heavenly Father that we're thankful for all the things we have.
Yah, like our arms, our legs, and our heads.
Exactly.
But my head is really hard to take off. (He says, as he puts his hands under his chin and pushes upward.)
Thank goodness for that. Okay...let's pray now.
But Heavenly Father can't hear me. He's too far away.
Actually, he can hear you even when he's far away. It's kind of like he's magic...he can hear you even from heaven.
But where is heaven?
Good question...some people say it's clear up in the sky.
Does Heavenly Father live in the chimney?
Uh...no. Even higher than the chimney.