You would want to port it if anything, sealed boxes have a natural ~12dB/oct rolloff starting at their F3, which is normally around 50-60hz. This means that no matter what sub (or how many subs) you got, the response would start falling off right around the crossover point, if your F3 was say 50hz, 25hz would actually be a full 15dB lower than the upper bass. In a car this isn't a problem because you have something called "cabin gain" which increases the sound's amplitude according to the car's transfer function, in a sedan you normally get a ~12dB/oct boost starting around 55hz which matches very well with a sealed box's natural rolloff, and the final result is normally a very flat response into the 20's or even the teens. In a room you have some gain but it's not nearly as drastic, so in order to get a solid response down to the 20's it's almost a necessity to port it. Luckily in a room you have plenty of space to port a sub, and the sacrificed upper end of its response isn't really a problem because most home speakers can go plenty low enough to take up the slack. If you want to build a ported box check out WinISD, for home use you normally want to tune it very low, if you'll be using it for movies then a tuning frequency in the high teens would be optimal, but the low to mid 20's wouldn't be bad. And you're going to want a much better sub than $15 can provide, that I promise you.