An air conditioner unit of 2 ton capacity was used in conjunction with desiccant wheel to achieve the Cromer cycle. The unit was constructed and installed in a test room during July to October 2007, at Technical College –Baghdad. The dimensions of the room are (6.5m length 2.8m width 2.37m height). Cromer cycle, including ducting system, desiccant wheel and motor, can be removed from the cycle, so the performance data with and without Cromer cycle can be gathered to investigate the effect of Cromer cycle on the power consumption and relative humidity within the conditioned space. Two type of desiccant materials were tested namely silica gel and active carbon. For each desiccant material, three thicknesses of desiccant materials were studied namely 2.5, 5, and 7.5 cm, also rotational speeds for desiccant wheel were studied, namely 10.7, 21, 42, 54.5, and 60 revolutions per hour (rph). The series of test showed that, the best COP and relative humidity control within the conditioned space was for the active carbon. The best COP was about 1.6 achieved with active carbon wheel of 5 cm thickness and 42 rph rotational speed. The latent heat ratio for Cromer cycle was 0.57 for the air conditioner using 5 cm thickness silica gel at a rotational speed of 42 rph. While the improvements in cycle COP under consideration without Cromer cycle was found to be 0.18. The study shows that Cromer cycle can reduce the indoor relative humidity from 80% to about 60% using active carbon of 5 cm wheel thickness.