I personally do not think that we need an A/C system in a Kendo Dojo, specially here in Southern California. However, the California building code requires us to have a heater. Since, the price of a heater only system and a heat/cold air system is not much different, we decided to go with the dual one. We are very spoiled. We have 4 huge A/C system for this Dojo.
It took them two whole days to drill 4 holes on this concrete wall.