X0306 4 2020-04-01 0 0001035983 COMFORT SYSTEMS USA INC FIX 0001205073 GEORGE WILLIAM III C/O COMFORT SYSTEMS USA, INC. 675 BERING DRIVE, SUITE 400 HOUSTON TX 77057 0 1 0 0 Chief Financial Officer Common Stock 2020-04-01 4 F 0 548 34.935 D 66479 D Common Stock 2020-04-01 4 F 0 408 34.935 D 66071 D Common Stock 2020-04-01 4 F 0 647 34.935 D 65424 D Forfeited shares are related to restricted stock units that vested on April 1, 2020 and were priced based on the average of the high and low stock price on April 1, 2020. Reflects forfeited shares related to the first vesting of restricted stock units granted on March 6, 2019. Price is based on the average of the high and low stock price on April 1, 2020. Reflects forfeited shares related to the second vesting of restricted stock units granted on March 7, 2018. Reflects forfeited shares related to the third and final vesting of restricted stock units granted on March 8, 2017. /s/ Laura F. Howell, by power of attorney 2020-04-03