屋
:
In standard Mandarin, 屋
is not commonly used as a noun by itself. Though, 房屋
is a common word, which is very similar to real estate
in English. e.g. 房屋中介
= Real estate agency
.
Another common usage of 屋
is in forming a name of a special kind of house. In such usage, it normally has a quite cozy feeling, e.g. 小屋
is a hut, 淑女屋
is a female clothing brand name.
I get feeling that the use of 屋
was may be introduced from Japan in modern times. Just a wild guess because 屋
seems much more common in Japanese.
房子
:
It is quite widely used, and is very similar to the English word "house".
E.g. 我有一幢房子
= I have a house
. 老房子
= Old house
, etc.
In general, 屋
is not as widely used in Mandarin as 房子
. And 屋
is used in a more formal fashion compared with 房子
.