The melting temp of borosilicate glass is higher. In glass production, most of the cost is the energy expenditure required to keep the kilns hot (they never tu

The melting temp of borosilicate glass is higher. In glass production, most of the cost is the energy expenditure required to keep the kilns hot (they never turn off). By dropping to a lower melting point glass, they can shave a substantial amount off their energy bill.