In earlier work, we used a vertical hot plate as a simple model of the human body, and it was important to determine whether or not our experimental results from the hot plate could really be applied to the body. Recently, thermal manikins have emerged as substitutes for the body, and this work tests whether or not the vertical hot plate can still be used as the substitute. Experiments are done with the abdominal segment of the thermal manikin and the vertical hot plate to investigate the effect of clothing construction factors like the size of air spaces and opening designs, open or closed, on quasi-clothing heat transfer. Results from the two methods agree with each other only when the size of the air space is 20 mm, and it is difficult to reproduce a setup with a precisely sized air space for the thermal manikin. The manikin has more experimental errors than the vertical hot plate, as clarified by results of the vertical hot plate model and the theoretical analysis that follows. The heat transfer coefficient of the open garment case is larger than that for the closed garment case, with proximity to the opening. In addition, the difference in the heat transfer coefficient is largest when the size of the air space is 10 mm. We have verified that the results of the vertical hot plate are helpful in understanding the results of the thermal manikin. Moreover, if the investigation of the effect of certain physical factors on heat transfer of quasi-clothing is performed analytically, it is not absolutely necessary to use a human model of actual dimensions, like a thermal manikin.