One of the largest factors that will come into play when deciding what height to hang a range hood is the height of the stove itself. Not all stoves are the same height. Some are taller than others and some have a back splash that increases the height of the stove even more. It will be impossible to hang the range hood lower than the top of the stove. This would also be a bad idea because then it would be difficult to cook on the stove because the range would be so low over the stove.
The height of the ceiling in your kitchen will also determine where the range hood is mounted. If you have a high stove, but a low ceiling, then your mounting options will be limited. You want the vent to be close enough to the ceiling to vent properly, but not so high that the stove is so much lower than the range that the range is not effectual. A balance must be reached between the height of the stove and the height of the ceiling.
The height of the vent itself will also play a large role in where it is hung. If the hood is too large to fit between the stove and the ceiling, then you will have to get a smaller hood to go in that spot. You also have to consider how much duct work the hood comes with and where the builder placed the hole for the venting system. If there is no hole you can cut one where you need to, but otherwise you have to work with the vent hole that is already there.
The average measurement for hanging a range hood is anywhere from 18 to 30 inches above the tallest point on the stove. This allows enough space to cook, see and fit large pots. Taller chefs will probably want to hang the range even higher above the stove. If you are not confident about where to place the range you can ask a building contractor or the company that sold you the range hood.