I have an Ascendant Audio 15" Avalanche that's been sitting around for a couple years and I want to put it in my house. I think it's in a 2.5 cf sealed box right now. I know home audio enclosures are usually much bigger (well for ported boxes at least). How would it sound if I threw that sub in the same box in my living room? Should I build a bigger box? Should I go ported instead? Seems like most home audio subs are ported.
Build the enclosure according to the requirements of the driver. Check the T/S parameters of the driver, either with the manufacturer or seller, and build what will work for the driver. Home audio subwoofers don't necessarilly need to be in a larger enclosure or a sealed vs vented box. However, most drivers meant for car audio seldom sound very good in a room due to the opposing T/S parameters which are used for each environment.
Not familiar with your driver or its electrical specs but I use a JBL 2235H 15" driver in a 5.5 Cu-Ft box with a 3.5"x12" tube port. JBL recommended this. The parameters of the enclosure necessary are generally given by the manufacturer of the driver.