Cellulose insulation

Cellulose insulation is plant fiber used in wall and roof cavities to insulate, draught proof and reduce noise. Building insulation in general is low-thermal-conductivity material used to reduce building heat loss and gain and reduce noise transmission. The main house of American president Thomas Jefferson's plantation Monticello was insulated with a form of cellulose in 1772. Cellulose was used more widely as an insulation material in Scandinavia from the 1920s. Many types of cellulosic materials have been used, including newspaper, cardboard, cotton, straw, sawdust, hemp and corncob. Modern cellulose insulation, made with recycled newspaper using grinding and dust-removing machines and adding a fire retardant, began in the 1950s and came into general use in the United States in the 1970s. Demand for insulation increased following the oil embargo of 1973–74, which caused energy costs for heating to skyrocket across the United States, driving interest in energy conservation. Insulation gained significant national attention in the U.S. as a cheap and available technology to increase the energy efficiency of homes. In 1977, following a particularly severe winter, a tax credit was given for U.S. homeowners who installed insulation. While in 1976 there were roughly 100 cellulose insulation firms with 125 plants in the US, by 1978 there were more than 350 firms with more than 500 plants.