What is meant by the calorigenic effect of thyroid hormones?

Calorigenic effect entails generation of metabolic heat. Thyroid hormones have calorigenic (thermogenic) effect which generate heat and may be related to psychological response to cold. There are two most important thyroid hormones T4 and T3. They accelerate glucose metabolism which increases heat production, basal metabolic rate and oxygen consumption. Under certain conditions T3 hormone  can also uncouple oxidative phosphorylation resulting to decreased ATP production and increasing heat liberated / mole of glucose