You may want to try Taulman 910 and 645, they do not "need" a heated bed but an enclosure is probably still a good idea..
Both suffer from poor diameter uniformity so can be an issue when trying to get tight tolerances but neither have much smell and 910 does not get wet as fast as other nylones
http://taulman3d.com/alloy-910-spec.html
http://taulman3d.com/910-features.html

http://taulman3d.com/nylon-645-spec.html
http://taulman3d.com/645-features.html

http://taulman3d.com/how-to-choose.html