Calculating heat load from return air ?

Hi,

Working in a legacy data centre (DC) with no electrical monitoring of use. Was planning to measure the airflow from the room, delta between return air temperature and delivery temperature and calculate heat load of room using formula:
CFM * Specific heat capacity of air(1.005)X Air density(1.2)* Delate t ......thinking this gives me heat load of room in kW. Am I missing something ?
Also I am using a shortridge flowhood meter. assuming I can measure airflow at a number of points on grill, average flow and then scale up by dividing area of grill by area of Room ?
Accept this is not exact, but assume it would be within 10%

You are missing a large portion, the moisture. This is load as well.