I also like to keep my car carpets clean and smelling fresh.  Car carpets get dirty very easily even with floor mats.  So my search began.  And what I discovered was there are simply no retail or "home units" that are powerful enough to extract the water back out of the carpeting.  So while doing research for myself I realized there are probably a lot of people just like me who would really like to have a quality hot water extractor for home use - but don't know what to look for or where to buy one.  Trust me on this simple fact:  It's not easy to find a good inexpensive unit.  I recommend talking to you local janitorial supply companies and then RENTING a unit.  Which is exactly what I ended up doing.  I rented a Mytee Speedster with 6 gallon tanks.  And while it was noisy, it did a nice job.

You would be amazed at just how much dark brown icky water you will pull out of carpets that look "clean".  Most carpet manufacturers recommend that you clean your carpets with hot water extraction every 12 to 18 months.  As noted carpet cleaners that use hot water extraction are recommended most.  Steam cleaners are not the same as hot water extraction. 

Personally, in time I will buy a unit for my home, but for now I'm happy with my rental decision.