We are testing an Air Handling Unit, we need to raise the internal temperature by 30 degrees to pass the test, but cannot exceed an energy input of 500W. It is a completely sealed unit. We have four fans constantly running, consuming 384W. Firstly, how can I work out what temperature they will raise the unit to? The fan manufacturer says that all energy input becomes heat (due to it being a closed system, but please lets not debate this, just accept it for the purpose of this question and use the full 384W). Secondly (if part 1 doesn't raise the temperature by 30 degrees), what size heater would we need to achieve the increase? Box Dimensions: 1.2x1.2x3.0m Fan Input: 384W Must not exceed: 500W (but I would like some answers even if they do exceed it to show me what we would need to do to achieve the required temperature increase) Also, is there a way to work out how many Watts are required to raise the temperature of air by 1 degree celsius in one hour?