The Ecoquiet PC uses a third less power than the standard computer and produces only 26 decibels of noise, according to RM, the educational computer company, which developed the device.
The basic package costs pound;654. The company says a suite of the computers could save a typical secondary more than pound;8,700 in electricity bills over five years.
Jonathan Robinson, Ecoquiet product manager, said: "This will hopefully mean that teachers experience less stress at work - spending all day raising your voice over noisy PCs is very wearing."
Other IT companies, including Viglen, are also developing quieter, more environmentally-friendly computer hardware for schools.