For your specific example, the most colloquial and natural way would be, to me:

Tu rentres quand (à la maison) ?

It works if she’s gone for days abroad and you don’t know if she comes back soon, it works if she has left for 5 minutes and is already on her way back home.

If I’m already at home and I know she’s on her way back, maybe I’d say:

Tu arrives quand ?

If I had a wife, that is.

Note that “maison” in such a case refers to the place you live, wether it’s a house, an apartment, a car, it could even be a country so yeah it’s “home”.

Maison is not only used for the building but is also used to refer to the place where you live.

Je suis à la maison. → I’m at home.

We can also use chez moi/ chez toi /chez nous etc.

Il est chez lui → He’s at home.

But in the case of your sentence what is really meant is “when will you be back home?” so we would use neither.

• Quand vas-tu rentrer ? /Quand rentres-tu ?

would probably be what most people say.

The answers to this question will tell you more on how the French language can express the idea of home in other contexts. And there a specific question on “Home sweet home”.

Complément non essentiel aux autres réponses, qui traitent les possibilités principales

There is a humourous, playful way to refer to the home and it is also used to mean « home » in the sense of « home country ». That’s the word “bercail” which has, among others, religious connotations. However it is a colloquial term and is not naturally used in a formal sentence.

• Quand tu rentres au bercail ?
• Quand rentres-tu au bercail ? (not likely)

• Possibilities:

Penates

Essentially used in the expression “regagner ses pénates”, which means goins back home.
It comes from the penates, latin gods of the hearth. http://www.expressio.fr/expressions/regagner-ses-penates.php

Foyer

Originally the place for the fire. Similar to “hearth” in English.
Third definition here:

Lieu où habite la famille, demeure ; la famille elle-même, le milieu familial : Recevoir un étranger à son foyer. Fonder un foyer. La chaleur d’un foyer.

• More administrative are:

Domicile

The place where you live, your official address.

Ménage

A place for living and the people who live there on a regular basis. Also used as a statistical unit.

Demeure

The physical building where someone lives.

• Finally, there are many, many familiar terms used to talk about ones’ house, including:

Bercail

Turne

Poulailler

Baraque

Crèche