The ideal height for your fan is 8-9 feet above the floor and at least 8.5 inches from the ceiling. that being said, if you have a large open to above ceiling this optimal height will not work. You will want the longest down rod possible. Alternatively if you are looking for the warming effect you will want to mount your fan closer to the ceiling. If you have low ceilings then you may need to go with a fan that mounts directly to the ceiling (a hugger Fan) as the blades of the fan can not be lower then 7 feet by Canadian Electrical Code.
the optimal down rod lengths are as followed:
|Ceiling Height||Downrod Length|
|9–11 ft (2.7–3.4 m)||7 in. (178 mm)|
|11–13 ft (3.4–4 m)||20 in. (508 mm)|
|13–14 ft (4–4.3 m)||32 in. (813 mm)|
|14–16 ft* (4.3–4.9 m*)||48 in.* (1219 mm*)|
|16–18 ft* (4.9–5.5 m*)||60 in.* (1524 mm*)|
While trying to achieve the ideal height it is important to note the longer the down rod is the harder the ceiling fan will be to balance. An improperly balanced ceiling fan will have a wobble to it. Typically the cheaper the ceiling fan the more likely the fan is to have a wobble and not balance properly, even when distribution weights are applied to the blades. This is something to consider when making your ceiling fan purchase.