NEC Table 220.12 gives you 2 VAs per square foot to calculate the minimum lighting load. Recepatacles are counted as 180 VA for simplex, duplex and triplex as per NEC 220.14(I)&(L). Motor loads are 125% of the largest motor plus the sum of the other motor loads. As for HVAC you take the highest of the air conditioning or heating leatings since they are not expected to be operating at the same time.