In the fine tradition of blurred boundaries and continually evolving microgenres associated with electronic music, "tech house" is a style of dance music that draws from both house and techno, as the name implies. By techno, I don't I'm not referring the overarching "all electronic music" sense in which many Americans use the term, but rather the specific genre. Tech house takes the minimalist approach of hard techno and brings the tempo down into house range and giving the percussion more of a groove, as opposed to the driving beat of techno. The main difference between tech house and acid house, as far as I can tell, is that the production of tech house is typically a little smoother and doesn't have those 303-ish acid lines. As I stated at the beginning of this writeup, the boundaries are a little blurry, and there is some spillover into the deep house and progressive house genres. If you're looking for tech house, some good producers/DJs to start with include Peace Division, Hipp-E & Halo, Layo & Bushwacka, and Rui Da Silva. Some good record labels for the genre include Eukahouse, Soma, and Siesta.
(Any comments are more than welcome, especially since I don't necessarily consider myself to be an expert in the genre.) | 
