<PAGE>

                                                                      EXHIBIT 24

                        ENCOMPASS SERVICES CORPORATION

                               POWER OF ATTORNEY

                           ANNUAL REPORT ON FORM 10-K


     The undersigned, in his capacity as a Director of Encompass Services
Corporation, does hereby appoint J. Patrick Millinor, Jr. and Darren B. Miller,
and each of them, severally, his true and lawful attorneys, or attorney, to
execute in his name, place and stead, in his capacity as a Director of said
Company, an Annual Report on Form 10-K for the fiscal year ended December 31,
1999, and any and all amendments to said Annual Report, and all instruments
necessary or incidental in connection therewith, and to file the same with the
Securities and Exchange Commission.  Each of said attorneys shall have the power
to act hereunder with or without the other of said attorneys and shall have full
power and authority to do and perform, in the name and on behalf of the
undersigned, in any and all capacities, every act whatsoever requisite or
necessary to be done in the premises, as fully and to all intents and purposes
as the undersigned might or could do in person, the undersigned hereby ratifying
and approving the acts of said attorneys and each of them.

     IN TESTIMONY WHEREOF, the undersigned has executed this instrument this
29th day of March, 2000.


                              /s/ ANDREW AFRICK
                              -------------------------
                              Andrew Africk
<PAGE>

                        ENCOMPASS SERVICES CORPORATION

                               POWER OF ATTORNEY

                          ANNUAL REPORT ON FORM 10-K


     The undersigned, in his capacity as a Director of Encompass Services
Corporation, does hereby appoint J. Patrick Millinor, Jr. and Darren B. Miller,
and each of them, severally, his true and lawful attorneys, or attorney, to
execute in his name, place and stead, in his capacity as a Director of said
Company, an Annual Report on Form 10-K for the fiscal year ended December 31,
1999, and any and all amendments to said Annual Report, and all instruments
necessary or incidental in connection therewith, and to file the same with the
Securities and Exchange Commission.  Each of said attorneys shall have the power
to act hereunder with or without the other of said attorneys and shall have full
power and authority to do and perform, in the name and on behalf of the
undersigned, in any and all capacities, every act whatsoever requisite or
necessary to be done in the premises, as fully and to all intents and purposes
as the undersigned might or could do in person, the undersigned hereby ratifying
and approving the acts of said attorneys and each of them.

     IN TESTIMONY WHEREOF, the undersigned has executed this instrument this
29th day of March, 2000.


                              /s/ VINCENT W. EADES
                              -----------------------------
                              Vincent W. Eades
<PAGE>

                        ENCOMPASS SERVICES CORPORATION

                               POWER OF ATTORNEY

                          ANNUAL REPORT ON FORM 10-K


     The undersigned, in his capacity as a Director of Encompass Services
Corporation, does hereby appoint J. Patrick Millinor, Jr. and Darren B. Miller,
and each of them, severally, his true and lawful attorneys, or attorney, to
execute in his name, place and stead, in his capacity as a Director of said
Company, an Annual Report on Form 10-K for the fiscal year ended December 31,
1999, and any and all amendments to said Annual Report, and all instruments
necessary or incidental in connection therewith, and to file the same with the
Securities and Exchange Commission.  Each of said attorneys shall have the power
to act hereunder with or without the other of said attorneys and shall have full
power and authority to do and perform, in the name and on behalf of the
undersigned, in any and all capacities, every act whatsoever requisite or
necessary to be done in the premises, as fully and to all intents and purposes
as the undersigned might or could do in person, the undersigned hereby ratifying
and approving the acts of said attorneys and each of them.

     IN TESTIMONY WHEREOF, the undersigned has executed this instrument this
29th day of March, 2000.


                              /s/ MICHAEL GROSS
                              --------------------------------
                              Michael Gross
<PAGE>

                        ENCOMPASS SERVICES CORPORATION

                               POWER OF ATTORNEY

                          ANNUAL REPORT ON FORM 10-K


     The undersigned, in his capacity as a Director of Encompass Services
Corporation does hereby appoint J. Patrick Millinor, Jr. and Darren B. Miller,
and each of them, severally, his true and lawful attorneys, or attorney, to
execute in his name, place and stead, in his capacity as a Director of said
Company, an Annual Report on Form 10-K for the fiscal year ended December 31,
1999, and any and all amendments to said Annual Report, and all instruments
necessary or incidental in connection therewith, and to file the same with the
Securities and Exchange Commission.  Each of said attorneys shall have the power
to act hereunder with or without the other of said attorneys and shall have full
power and authority to do and perform, in the name and on behalf of the
undersigned, in any and all capacities, every act whatsoever requisite or
necessary to be done in the premises, as fully and to all intents and purposes
as the undersigned might or could do in person, the undersigned hereby ratifying
and approving the acts of said attorneys and each of them.

     IN TESTIMONY WHEREOF, the undersigned has executed this instrument this
29th day of March, 2000.


                              /s/ WILLIAM P. LOVE, JR.
                              ----------------------------------
                              William P. Love, Jr.
<PAGE>

                        ENCOMPASS SERVICES CORPORATION

                               POWER OF ATTORNEY

                          ANNUAL REPORT ON FORM 10-K


     The undersigned, in his capacity as a Director of Encompass Services
Corporation, does hereby appoint J. Patrick Millinor, Jr. and Darren B. Miller,
and each of them, severally, his true and lawful attorneys, or attorney, to
execute in his name, place and stead, in his capacity as a Director of said
Company, an Annual Report on Form 10-K for the fiscal year ended December 31,
1999, and any and all amendments to said Annual Report, and all instruments
necessary or incidental in connection therewith, and to file the same with the
Securities and Exchange Commission.  Each of said attorneys shall have the power
to act hereunder with or without the other of said attorneys and shall have full
power and authority to do and perform, in the name and on behalf of the
undersigned, in any and all capacities, every act whatsoever requisite or
necessary to be done in the premises, as fully and to all intents and purposes
as the undersigned might or could do in person, the undersigned hereby ratifying
and approving the acts of said attorneys and each of them.

     IN TESTIMONY WHEREOF, the undersigned has executed this instrument this
29th day of March, 2000.


                              /s/ DONALD L. LUKE
                              -----------------------------------
                              Donald L. Luke

<PAGE>

                        ENCOMPASS SERVICES CORPORATION

                               POWER OF ATTORNEY

                          ANNUAL REPORT ON FORM 10-K


     The undersigned, in his capacity as a Director of Encompass Services
Corporation, does hereby appoint J. Patrick Millinor, Jr. and Darren B. Miller,
and each of them, severally, his true and lawful attorneys, or attorney, to
execute in his name, place and stead, in his capacity as a Director of said
Company, an Annual Report on Form 10-K for the fiscal year ended December 31,
1999, and any and all amendments to said Annual Report, and all instruments
necessary or incidental in connection therewith, and to file the same with the
Securities and Exchange Commission.  Each of said attorneys shall have the power
to act hereunder with or without the other of said attorneys and shall have full
power and authority to do and perform, in the name and on behalf of the
undersigned, in any and all capacities, every act whatsoever requisite or
necessary to be done in the premises, as fully and to all intents and purposes
as the undersigned might or could do in person, the undersigned hereby ratifying
and approving the acts of said attorneys and each of them.

     IN TESTIMONY WHEREOF, the undersigned has executed this instrument this
29th day of March, 2000.



                              /s/ LUCIAN L. MORRISON
                              -------------------------------------
                              Lucian L. Morrison

<PAGE>

                        ENCOMPASS SERVICES CORPORATION

                               POWER OF ATTORNEY

                          ANNUAL REPORT ON FORM 10-K


     The undersigned, in his capacity as a Director of Encompass Services
Corporation, does hereby appoint J. Patrick Millinor, Jr. and Darren B. Miller,
and each of them, severally, his true and lawful attorneys, or attorney, to
execute in his name, place and stead, in his capacity as a Director of said
Company, an Annual Report on Form 10-K for the fiscal year ended December 31,
1999, and any and all amendments to said Annual Report, and all instruments
necessary or incidental in connection therewith, and to file the same with the
Securities and Exchange Commission.  Each of said attorneys shall have the power
to act hereunder with or without the other of said attorneys and shall have full
power and authority to do and perform, in the name and on behalf of the
undersigned, in any and all capacities, every act whatsoever requisite or
necessary to be done in the premises, as fully and to all intents and purposes
as the undersigned might or could do in person, the undersigned hereby ratifying
and approving the acts of said attorneys and each of them.

     IN TESTIMONY WHEREOF, the undersigned has executed this instrument this
29th day of March, 2000.



                              /s/ BROOKS NEWMARK
                              -------------------------------
                              Brooks Newmark
<PAGE>

                        ENCOMPASS SERVICES CORPORATION

                               POWER OF ATTORNEY

                          ANNUAL REPORT ON FORM 10-K


     The undersigned, in his capacity as a Director of Encompass Services
Corporation, does hereby appoint J. Patrick Millinor, Jr. and Darren B. Miller,
and each of them, severally, his true and lawful attorneys, or attorney, to
execute in his name, place and stead, in his capacity as a Director of said
Company, an Annual Report on Form 10-K for the fiscal year ended December 31,
1999, and any and all amendments to said Annual Report, and all instruments
necessary or incidental in connection therewith, and to file the same with the
Securities and Exchange Commission.  Each of said attorneys shall have the power
to act hereunder with or without the other of said attorneys and shall have full
power and authority to do and perform, in the name and on behalf of the
undersigned, in any and all capacities, every act whatsoever requisite or
necessary to be done in the premises, as fully and to all intents and purposes
as the undersigned might or could do in person, the undersigned hereby ratifying
and approving the acts of said attorneys and each of them.

     IN TESTIMONY WHEREOF, the undersigned has executed this instrument this
29th day of March, 2000.


                              /s/ M. JUDE REYES
                              ---------------------------
                              M. Jude Reyes


<PAGE>

                        ENCOMPASS SERVICES CORPORATION

                               POWER OF ATTORNEY

                          ANNUAL REPORT ON FORM 10-K


     The undersigned, in his capacity as a Director of Encompass Services
Corporation, does hereby appoint J. Patrick Millinor, Jr. and Darren B. Miller,
and each of them, severally, his true and lawful attorneys, or attorney, to
execute in his name, place and stead, in his capacity as a Director of said
Company, an Annual Report on Form 10-K for the fiscal year ended December 31,
1999, and any and all amendments to said Annual Report, and all instruments
necessary or incidental in connection therewith, and to file the same with the
Securities and Exchange Commission.  Each of said attorneys shall have the power
to act hereunder with or without the other of said attorneys and shall have full
power and authority to do and perform, in the name and on behalf of the
undersigned, in any and all capacities, every act whatsoever requisite or
necessary to be done in the premises, as fully and to all intents and purposes
as the undersigned might or could do in person, the undersigned hereby ratifying
and approving the acts of said attorneys and each of them.

     IN TESTIMONY WHEREOF, the undersigned has executed this instrument this
29th day of March, 2000.



                              /s/ JOHN M. SULLIVAN
                              --------------------------------------
                              John M. Sullivan