Exhibit 10.1

SUMMARY OF 2009 INCENTIVE COMPENSATION PLAN

        On March 26, 2009, the Compensation Committee of the Board of Directors
of Comfort Systems USA, Inc. (the "Compensation Committee") adopted the 2009
Senior Management Annual Performance Plan, and authorized certain equity grants
under the Company's Long-term Incentive Plan. The Named Executive Officers are
Mr. William F. Murdy, Chairman of the Board of Directors and Chief Executive
Officer; Mr. William George, III, Executive Vice President and Chief Financial
Officer; Mr. Brian E. Lane, Executive Vice President and Chief Operating
Officer; Mr. Thomas N. Tanner, Executive Vice President—Corporate Development;
and Ms. Julie S. Shaeff, Senior Vice President and Chief Accounting Officer.

2009 Incentive Compensation Plan for Executive Officers

        The annual incentive compensation for the Named Executive Officers is
provided under a shareholder approved plan intended to satisfy the requirements
for deductibility of performance-based compensation under Section 162(m) of the
Internal Revenue Code. The plan consists of two distinct elements. The first
element of the plan rewards the senior executives of the Company for obtaining
certain earnings per share ("EPS") target thresholds (the "Objective Bonus").
The second element of the plan rewards the achievement of certain performance
metrics individualized for each executive (the "Subjective Bonus").

        For the Objective Bonus, the Committee has set a bonus range based on a
target that is correlated with the Company's annual EPS. The range for the
Objective Bonus for Messrs. Murdy, George, Lane and Tanner will be 40 percent to
150 percent of 90 percent of their respective annual base salaries. For
Ms. Shaeff the range for the Objective Bonus will be 40 percent to 150 percent
of 30 percent of her annual base salary. The Objective Bonus is zero until a
certain EPS threshold is met, it then scales from 40 percent to 100 percent on a
straight-line basis as it moves from 75% of the EPS target to 100% of the EPS
target. Should the Company's performance exceed the EPS target, it then scales
from 100 percent to 150 percent on a straight-line basis as it moves from 100%
of the EPS target to 155% of the EPS target. With regard to the Subjective
Bonus, each executive is reviewed individually and at the sole discretion of the
Committee is awarded a bonus within a set range of potential outcomes based on a
percentage of annual base salary. For Messrs. Murdy, George, Lane, and Tanner,
the range is 0 to 100 percent of 10 percent of annual base salary; for
Ms. Shaeff, the range is 0 to 100 percent of 20 percent of annual base salary.

Long-term Incentive Plan Grants

        The Committee further determined grants under the Company's Long-term
Incentive Plan. These grants were determined based on the closing price of the
Company's common stock on March 26, 2009, the date the Committee met to approve
the grants. These grants consisted of an award of performance stock as well as a
grant of options. The performance stock is tenure as well as performance based;
it is granted a on a three-year equal vesting schedule, and vests only if the
Company meets certain performance requirements prior to each of the three
vesting periods. If the performance threshold is met, the performance stock
awards vest on a sliding scale from 0 to 100 percent of the portion of the award
scheduled to vest on a straight-line basis. The number of shares vesting may
also be reduced by the Compensation Committee on a discretionary basis. The
option grants vest on a three-year schedule and do not have a performance
vesting requirement.

        The 2009 awards were granted to the following executives for the purpose
of providing an incentive for those individuals to work for the Company's
long-term success: Mr. Murdy was granted 59,216 shares of performance stock and
49,347 options. Messrs. George and Tanner were granted 25,994 shares of
performance stock and 21,662 options respectively. Mr. Lane was granted 23,267
shares of performance stock and 19,389 options. Ms. Shaeff was granted 10,330
shares of performance stock and 8,608 options.

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