Why silicone heater has special smell?

Silicone heater is a kind of heater that uses heat generated by a heating wire and thermally insulated with silicone rubber.

Silicone rubber is sodium sulfate and weak silicic acid (H3SiO3) produced by the reaction of sulfuric acid and sodium silicate. Because weak silicic acid is unstable, it becomes silica and water. Then, the water is dried by heating to obtain silica gel. Silica is non-toxic and odorless, but the silica gel will evaporate acid gas, which will smell a little irritating. However, the silicone heating heaters we make are all processed by gas deodorization. So the smell is not too much to harm.