It makes sense to me, but sometimes people balk when they find that it costs more, or they have to pay more at least, to have a duplex inspected than a home of the same size. If you think about it, that should not be such a surprise. The uninitiated will think that the duplex is just a bigger house. Fact is, there is some truth to that. There is usually only one roof and the exterior. However, think of all the other things that are multiple. There are almost always two electrical systems and panels to inspect. There are two or more water heaters, and two or more furnaces or a myriad of electric baseboard heaters. There are multiple bathrooms as well, along with a couple kitchens. It depends on the house, but a number of them have divided attics and crawl spaces that have to be individually inspected too. Then there are frequently multiple decks or balconies. So, even though some of the exterior of the home is shared, there is way more for an inspector to do in a 3000 sq foot duplex than in a single family 3000 sq foot home. Now, as far as rates, my rate is not double for a duplex compared to a home of that size. It is only up about $50 over a house of the same size.