1 EXHIBIT 12 INTEGRATED ELECTRICAL SERVICES, INC. AND SUBSIDIARIES RATIO OF EARNINGS TO FIXED CHARGES (IN THOUSANDS OF DOLLARS) Nine Months Year Ended Six Months Ended Years Ended December 31, Ended September 30, March 31, ------------------------------------ September 30, ---------------------- ----------------------- 1994 1995 1996 1997 1997 1998 1998 1999 ----------- ----------- ---------- ------------ ---------- ---------- ----------- ----------- CONSOLIDATED Earnings: Income before income taxes . . . . . . . . . $ 712 $ 1,549 $ 6,136 $ 6,143 $ 7,298 $12,638 $(12,570) $32,793 Fixed charges . . . . . . 249 325 223 251 283 2,486 227 5,588 ------- ------- -------- ------- ------- ------- -------- ------- $ 961 $ 1,874 $ 6,359 $ 6,394 $ 7,581 $15,124 $(12,343) $38,381 ======= ======= ======== ======= ======= ======= ======== ======= Fixed Charges: Interest expense . . . . . $ 172 $ 286 $ 171 $ 164 $ 214 $ 1,161 $ 59 $ 4,923 Portion of rental cost representing interest . 77 39 52 87 69 1,325 168 665 ------- ------- -------- ------- ------- ------- -------- ------- $ 249 $ 325 $ 223 $ 251 $ 283 $ 2,486 $ 227 $ 5,588 ======= ======= ======== ======= ======= ======= ======== ======= Ratio of earnings to fixed charges . . . . . . . . . 3.9x 5.8x 28.5x 25.5x 26.8x 6.1x -- x 6.9x ======= ======= ======== ======= ======= ======= ======== ======= PRO FORMA: Earnings: Income before income taxes . . . . . . . . . $83,951 $35,534 Fixed charges . . . . . . 6,095 5,769 ------- ------- $90,046 $41,303 ======= ======= Fixed Charges: Interest expense . . . . . $ 4,292 $ 4,923 Portion of rental cost representing interest . 1,803 846 ------- ------- $ 6,095 $ 5,769 ======= ======= Ratio of earnings to fixed charges . . . . . . . . . 14.8x 7.2x ======= ======= PRO FORMA AS ADJUSTED: Earnings: Income before income taxes . . . . . . . . . $72,714 $32,848 Fixed charges . . . . . . 17,332 8,455 ------- ------- $90,046 $41,303 ======= ======= Fixed Charges: Interest expense . . . . . $15,529 $ 7,609 Portion of rental cost representing interest . 1,803 846 ------- ------- $17,332 $ 8,455 ======= ======= Ratio of earnings to fixed charges . . . . . . . . . 5.2x 4.9x ======= =======