The report gives results of a series of computer runs using the DOE-2.1E building energy model, simulating a small office in a hot, humid climate (Miami). These simulations assessed the energy and relative humidity (RH) penalties when the outdoor air (OA) ventilation rate is increased from 5 to 20 cfm/person to improve indoor air quality. The effect was systematically assessed of each building and mechanical system parameter on the energy penalty resulting from increased OA. The cost and effectiveness were also assessed of methods for reducing elevated-RH hours. The parameters offering the greated practical potential for energy savings are conversion to: very efficient lighting and equipment; very efficient cooling coils; to a variable air volume (from a constant volume) system; cold-air distribution; or improved glazing or roof resistance to heat transfer. If the OA increase were accompanied by any one of these modifications, the energy penalty would be significantly reduced (comparing the modified system at 20 against the baseline at 5 cfm/person).