Amathuluzi okulawula izinga lokushisa, azaziwa nangokuthi ama-valve e-thermostatic, ayisicelo esijwayelekile sama-valve okulawula ukuhamba emkhakheni wokulawula izinga lokushisa. Isimiso sawo esiyisisekelo ukuwulawula umthamo wokungena komkhiqizo opholile (noma oshisayo) ezikhumulweni zokushintshisana kokushisa, kumayunithi wokupholisa, noma kwezinye izinsiza ezisebenzisa ukushisa noma ukupholisa ukuze kulawulwe izinga lokushisa lokuphuma kwezinsiza. Uma umthwalo ushintsha, umthamo uyashintshwa ngokushintsha ukuvulwa kwe-valve ukuze kukhishwe imiphumela yokushintsha komthwalo futhi kubuyiselwe izinga lokushisa kwinani elibekiwe.