The difference between Commercial and Residential door hardware comes down to grade or quality and better grade means you can pretty much use it more without it breaking on you. You would probably never put a residential door knob (or any other type of hardware for that matter) on a commercial application like a public office building like a dentist's office for example, a residential door knob wouldn't last a month - this goes for any type of door hardware, like hinges and any other misc. hardware for doors too. Commercial doors are going to get a lot of use, whether its the bathroom or the front door. And for Residential applications like your home, you don't need commercial grade hardware for your home a simple 3 grade door knob or residential hinges should do the trick. Unless you have a large family like a customer who called in did and the door knob would keep breaking within a few months and they had to replace it two to three times, in that case maybe you do need a commercial grade door knob. Commercial: Commercial hardware generally has an ASI grade of 1 or 2, one being the highest and most heavy duty. Commercial hardware not only have heavy duty grades, but also lots of commercial buildings require the hardware to meet certain specifications such as UL Listing, ADA Compliant. You can find all different types of commercial hardware to fit the application you have, check here. Residential: Residential hardware is used for your home. You don't have a ton of people opening and shutting your door a hundred times a day - well maybe you do (like the man I mentioned earlier) I don't really know, but nine times out of ten I am sure most homes don't. Residential hardware is made for doors that don't get as much wear and tear - if you are using a residential door knob for example on a commercial application and it breaks more than once (which it most likely will) and even though some manufactures have warranties that cover for years or even a lifetime - the warranty may be voided if the hardware is being used on a commercial application rather than residential. So make sure you are using your residential hardware on residential applications if you want your warranty to cover replacements.