No, you should not steam clean hardwood floors. Cleaning your hardwood floors with a steam cleaner or with excess moisture will damage your floors and cause them to warp. In many cases using a steam cleaner on your floors will void their warranty. Always consult the warranty guide for your floor before using any cleaning products. Some steam cleaner manufacturers may boast that their products are safe to use on hardwood floors (with the disclaimer that the floors must be properly sealed) but both the Wood Floor Covering Association and the National Wood Floor Covering Association do not recommend using steam cleaning products on hardwood. There are also no major hardwood floor manufacturers that recommend using steam cleaners on hardwood floors. Refer to the manufacturer of your floor or to your local Flooring America/Flooring Canada for other cleaning options that would be appropriate for your floor.