1 EXHIBIT 12 INTEGRATED ELECTRICAL SERVICES, INC. AND SUBSIDIARIES RATIO OF EARNINGS TO FIXED CHARGES (IN THOUSANDS OF DOLLARS) Nine Months Year Ended Quarter Ended Years Ended December 31, Ended September 30, December 31, ------------------------------------ September 30, ---------------------- ----------------------- 1994 1995 1996 1997 1997 1998 1997 1998 ----------- ----------- ---------- ------------ ---------- ---------- ----------- ----------- CONSOLIDATED Earnings: Income before income taxes . . . . . . . . . $ 712 $ 1,549 $ 6,136 $ 6,143 $ 7,298 $12,638 $(1,180) $15,792 Fixed charges . . . . . . 249 325 223 251 283 2,486 265 2,026 ------- ------- -------- ------- ------- ------- ------- ------- $ 961 $ 1,874 $ 6,359 $ 6,394 $ 7,581 $15,124 $ (915) $17,818 ======= ======= ======== ======= ======= ======= ======= ======= Fixed Charges: Interest expense . . . . . $ 172 $ 286 $ 171 $ 164 $ 214 $ 1,161 $ 225 $ 1,695 Portion of rental cost representing interest . 77 39 52 87 69 1,325 40 331 ------- ------- -------- ------- ------- ------- ------- ------- $ 249 $ 325 $ 223 $ 251 $ 283 $ 2,486 $ 265 $ 2,026 ======= ======= ======== ======= ======= ======= ======= ======= Ratio of earnings to fixed charges . . . . . . . . . 3.9x 5.8x 28.5x 25.5x 26.8x 6.1x -- x 8.8x ======= ======= ======== ======= ======= ======= ======= ======= PRO FORMA: Earnings: Income before income taxes . . . . . . . . . $64,090 $15,537 Fixed charges . . . . . . 5,736 2,145 ------- ------- $69,826 $17,682 Fixed Charges: Interest expense . . . . . $ 4,292 $ 1,708 Portion of rental cost representing interest . 1,444 437 ------- ------- $ 5,736 $ 2,145 ======= ======= Ratio of earnings to fixed charges . . . . . . . . . 12.2x 8.2x ======= ======= PRO FORMA AS ADJUSTED: Earnings: Income before income taxes . . . . . . . . . $52,853 $13,380 Fixed charges . . . . . . 16,973 4,302 ------- ------- $69,826 $17,682 ======= ======= Fixed Charges: Interest expense . . . . . $15,529 $ 3,865 Portion of rental cost representing interest . 1,444 437 ------- ------- $16,973 $ 4,302 ======= ======= Ratio of earnings to fixed charges . . . . . . . . . 4.1x 4.1x ======= =======