I was trying to convert a quantity in BTU/(ft*hr*F) to W/(m*C) and I can do it just fine by using a conversion factor from a table online, but what I want to know is how to come up with that conversion factor. The conversion factor I looked up and have been using is 1 BTU/(ft*hr*F) = 1.73 W/(m*C). I tried to get this using dimensional analysis but it does not work. I think the problem is going from F to C because they do not have the same zero point. If that is the problem and I can't solve this with dimensional analysis how could I do it.