Here is the HTML entity list on the W3C's website itself. http://www.w3.org/TR/REC-html40/sgml/entities.html
The HTML entities are only good for Latin characters, mathematical symbols, Greek letters and mark-up–significant and internationalisation characters. The house symbol is neither of these =(
It's a Unicode symbol http://www.fileformat.info/info/unicode/char/2302/index.htm which can be written using the SGML (Standard Generalised Mark-up Language) escapes ⌂ (decimal) or ⌂ (hexadecimal), but the decimal one is preferred for its shortness: ?.
Unfortunately, I couldn't find a filled in one.