A residential air sealing technician will need to know about buildings. An associate's degree in building science may be helpful. These degrees's can cost around $8 to $10 thousand, depending on where you go. It is also recommended to have LEED certification. The test costs around $250. Another route you can take is the BOMA Energy Efficiency Program (BEEP). The program costs $175. Whatever path you choose, this is a very good green career.