This paper conducted a study on how the heat radiation of light emitting diode (LEI)) luminaires affects the indoor temperature increase. The effect was compared with that of a 20 W compact fluorescent lamp (CFL) and a 50 W MuG halogen lamp which are most widely used inside of cruises, a LED downlight and a 4W MRI6 LED replacing each of them. We installed a luminarie inside a thermally shielded chamber, measuring the temperature changes under the same volume every 5 minutes and compared the result with theoretically calculated heat radiation, The temperature changes in the chamber was measured four times, on seven hours` period in order to keep sufficient time once the temperature reaches the thermal equilibrium state. The results showed that the temperature of the 20 W E26 CFL and the 10 W LED downlight increased by 21,1`C and 10.4t respectively, while that of the 50 W halogen MRI6 and the 4 W LED MR16 increased by 33.9t and 4.8t respectively. The experimental heat radiation were calculated from the results and the experimental heat radiation of the CFL and the LED downlight were 171.5 cal and 86.5 cal, and those of the halogen MR16 and the LED MR16 were 275.3 cal and 36.5 cal, Therefore, the heat radiation was reduced by 49.5% and 86.7%, respectively, by replacing conventional light source with LED. In conclusion, we can expect a reduction of power consumption in air condition system and the effect on indoor temperature increase by application of LED luminaires.