It seems like "house" is usually translated as 房子 (fáng zi) in standard Chinese, although 屋 (wū) is also a common translation, especially in Cantonese.
Is there a difference between the two? When should I use one over the other (in Standard Chinese)?
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.
It might be a bit hard to explain it in English. I may sounds incoherently.
First to clarify, '子' is a magic character. It's not fair to put it after one but not the other. Some usage of '房子' could be replaced with '屋子', but very few with just '屋'. So I will just discuss 房 and 屋.
As many synonym characters, their origins had different specific usage.
As for "房子" and "屋子", it's not precise science, but more about which one sounds or feels right. If you are talking, or casual writing, it's always ok to use "房子" for house, while sometimes it will be weird if using "屋子". I believe "屋" will be hardly used. It normally use for short or elegant. For example, the Sherlock Holmes story The Empty House is translated to 《空屋》.
PS: Sorry if I made it even more confused.
屋also means home while房子only means house and room, though it's a dialect usage... 来我屋瞧瞧 (come to my home and take a look) 来我房子瞧瞧 (come to my room and take a look). – Mike Manilone Feb 24 '13 at 18:25