On what grounds did Potifar merit that his house became blessed?
Targum Yonasan: On th merit of Yosef. 1
Oznayim la'Torah (citing R. Moshe ha'Darshan): Because he placed it in the charge of Yosef 2 and Yosef's house was worthy of blessing, even though Potifar and his wife were steeped in immorality, which generally leads to poverty.
How long was Yosef in Potifera's house?
Da'as Zekenim, Hadar Zekenim: He was there one year - ba'Bayis in winter, u'va'Sadeh in summer.
Seider Olam: He was one year in Potifera's house, and twelve years in the dungeon. 1
Why does it say "Beis ha'Mitzri"?
Malbim: Even though he was in a Mitzri's house, which inhibits success of Hashgachah, it was blessed due to Yosef.
What do we include from "b'Chol Asher Yesh Lo ba'Bayis uva'Sadeh"?
Malbim: B'Chol Asher Yesh Lo includes the property he had beforehand; ba'Bayis is expenditures, and va'Sadeh is income.
Ha'amek Davar: After appointing him over his house, he appointed him over Chol Asher Yesh Lo. It is as if it is written Chol Asher Lo v'Chol Yesh Lo, i.e. all his property, and his service of the king (refer to 39:4:152:2).