The easiest way to work out whether an address is a residence or a business is to use the Internet. You may be able to find this out by searching on address databases. If you need a further check, you can also use map sites to "visit" the address to see if the structure looks like a home or a business.
Search the term "reverse address" in your web browser. You will get a number of websites that reverse an address to tell you who lives there. Simply pick a site -- White Pages, for example -- and select the reverse address tab if you are not automatically directed to that page. Type in the address details -- search results should show a house symbol, or an "H," for residential addresses, or a "W" for businesses. In some cases, home-based businesses show up in apartment buildings. In this case, your results may show a mix of residential and business listings.
Click on the "map" tab beside the listing or look down the page to see if the site has a map of the area. Look for a satellite picture option so you can take a look at an image of the building. In some cases the page will link to one map company instead of another, so the picture quality and options may differ.
Go to Mapquest and search the address by clicking the Get Directions tab. Once the map has loaded, click on Satellite and get a satellite picture of the address and surrounding neighborhood. From this you can usually if tell if the address is a residence or a business.
Go to Google Maps and enter the address into the search field. Switch from map to satellite view and click on "Street View." You'll see a street-level photograph of the address, which will let you know if you are looking at a residence or a business.
Go to the United States Postal Service (USPS) website and put in the address, minus the zip code, and search. The address will come up with how many units are at the address. Multiple units can mean that a building could be either an office building or apartments, but the USPS site will not show this. They have a link to White Pages/Yellow Pages to do a search for this information.