Shaw Company produced 720 units. Its overhead allocation base is DLH and its standard amount per allocation base is 8 DLH per unit. Its standard overhead rate is $10 per DLH. The flexible overhead budget at an activity level of 720 units shows $28,000 in variable overhead costs and $32,000 in fixed overhead costs. Compute the volume variance. (Indicate the effect of the variance by selecting favorable, unfavorable, or no variance.)