Document:

EXHIBIT 10.3

                           NOTE MODIFICATION AGREEMENT

      THIS NOTE MODIFICATION AGREEMENT is entered into effective as of August 8,
2000, and is binding on Mark Shambaugh (the "Holder"), and all of his assignees,
successors in interest and any other person or entity claiming by or through any
of them. Reference is hereby made to (i) each of those four certain Convertible
Subordinated Note(s) due November 15, 2001, each in the original principal
amount of $7,437,500 made by the Comfort Systems USA, Inc., a Delaware
corporation (the "Company"), in favor of the Holder, each as amended effective
as of July 1, 1999 (each individually a "Note", and collectively, the "Notes"),
and (ii) the Agreement and Plan of Merger dated November 15, 1998 by and among
the Company, CS42 Acquisition Corp., a Delaware corporation, Shambaugh & Son,
Inc., an Indiana corporation ("S&S") and the Holder (the "Merger Agreement").

      WHEREAS, the Company has notified the holder pursuant to the Merger
Agreement of certain liabilities (the "Potential Liabilities") to which S&S is
or may be liable and which relate to the fire protection activities of the
Company with GTE North, Incorporated and its affiliates ("GTE") prior to the
date of the Merger Agreement; and

      WHEREAS, the parties to such dispute have indicated that they are willing
to settle all civil liabilities with respect to such matter upon the payment by
S&S a cash settlement (the "Settlement Amount") to GTE; and

      WHEREAS, payment of the Settlement Amount would constitute Damages under
the Merger Agreement; and

      WHEREAS, pursuant to the Merger Agreement the Company is entitled to
offset Damages as set forth therein against amounts payable pursuant to the
Notes; and

      WHEREAS, the civil liabilities satisfied and released as consideration for
the Settlement Amount do not necessarily comprise all of the Potential
Liabilities; and

      WHEREAS, the Holder and the Company desire to document and clarify the
note modification required to effectuate such right of offset,

      NOW THEREFORE, the Holder and the Company hereby agree as follows:

      1.  Holder hereby represents that he is the holder of the Notes free and
          clear of all liens and obligations, that he has not transferred or
          alienated his interest in the Notes, and that he has full power to
          enter into this Agreement and thereby modify the Notes.

      2.  Holder acknowledges and agrees that, if and when the Company pays the
          Settlement Amount, the Company may offset such payment by reducing the
          principal of each Note by an amount equal to the Settlement Amount
<PAGE>
          minus the Indemnification Threshold divided by four. Such amounts
          shall be taken from the principal amounts due and payable on January
          1, 2001. The offset and reduction shall be effective as of the date
          that the Company actually pays the Settlement Amount.

      3.  To the extent that the Company has additional, valid Damages with
          respect to the Potential Liabilities, such Damages shall be gathered
          and itemized by the Company and reported to Holder by the Company.
          Such offset amounts, once determined, shall be taken from the
          principal amounts due and payable on January 1, 2001. The offset and
          reduction shall be effective as of the date that the Company delivers
          a final itemized accounting to the Holder pursuant to this Agreement.

Except for the offsets and reductions specifically set forth under this
Agreement, each of the Notes, as amended, are hereby reaffirmed in all respects.

COMFORT SYSTEMS USA, INC.

/s/ William Murdy                   /s/ Mark Shambaugh
WILLIAM MURDY                       MARK SHAMBAUGH
CHIEF EXECUTIVE OFFICEREXHIBIT 10.4

                           NOTE TERMINATION AGREEMENT

      THIS NOTE TERMINATION AGREEMENT is entered into effective as of June 23,
2000, by and among Salvatore Fichera and Salvatore Giardina (collectively, the
"Pledgors"), Sorce Properties LLC, a New Jersey limited liability company
("Borrower"), and F&G Mechanical Corporation, a Delaware corporation ("Lender").
Reference is hereby made to (i) that certain Promissory Note by Borrower in
favor of Lender dated February 12, 1998 in the principal amount of $5,600,000
(the "Note") and (ii) that certain Pledge Agreement dated as of February 12,
1998 by the Pledgors in favor of Lender (the "Pledge Agreement"). Terms not
otherwise defined herein shall have the same definition as is set forth in the
Pledge Agreement.

      Lender hereby represents that it is the holder of the Note free and clear
of all liens and obligations, that it has not transferred or alienated its
interest in the Note, and that it has full power to enter into this agreement
and thereby terminate the Note. Each of the Pledgors hereby represents that he
is the holder of the Pledged Stock designated in his name free and clear of all
liens and obligations, that he has not transferred or alienated his interest in
the Note, and that he has full power to enter into this agreement and deliver
the Pledged Stock.

      Each of the Pledgors hereby irrevocably transfers all of its right, title
and interest in the Collateral (represented by Stock Certificates CS0520 in the
name of Salvatore Fichera, and CS0524 in the name of Salvatore P. Giardina, each
for 180,262 shares of the Common Stock of Comfort Systems USA, Inc.), and
simultaneously with his execution hereof will deliver stock powers, executed in
blank, pertaining to the Pledged Shares. The Lender agrees that upon receipt of
a fully executed Note Termination and the required stock powers it will, without
other payment in respect thereof, cancel the Obligations and deliver to the
Borrower the original Note marked "Cancelled".

      IN WITNESS WHEREOF, the parties set forth above hereby execute this Note
Termination at the date set forth above.

F&G MECHANICAL CORPORATION       SORCE PROPERTIES LLC

/s/ William George               /s/ Santo Sorce
WILLIAM GEORGE                   SANTO SOURCE
VICE PRESIDENT                   PRESIDENT

/s/ Salvatore Fichera            /s/ Salvatore P. Giardina
SALVATORE FICHERA                SALVATORE P. GIARDINAEXHIBIT 10.5

                            COMFORT SYSTEMS USA, INC.

                       THIRD AMENDMENT TO CREDIT AGREEMENT

      This THIRD AMENDMENT TO CREDIT AGREEMENT (this "AMENDMENT") is dated as of
August 11, 2000 and entered into by and among COMFORT SYSTEMS USA, INC., a
Delaware corporation (the "COMPANY"), the other Credit Support Parties (as
defined in Section 4 hereof), the Subsidiaries of the Company listed on the
signature pages hereto as Guarantors (together with each other Person who
subsequently becomes a Guarantor, collectively the "GUARANTORS"), the banks and
other financial institutions listed on the signature pages hereto under the
caption "BANKS" (together with each other Person who becomes a Bank,
collectively the "BANKS"), BANK ONE, TEXAS, N.A., individually as a bank ("BOT")
and as administrative agent for the other Banks (in such capacity together with
any other Person who becomes the administrative agent, the "ADMINISTRATIVE
AGENT"), BANKERS TRUST COMPANY, individually as a Bank ("BTCO") and as
syndication agent for the other Banks (in such capacity together with any other
Person who becomes the syndication agent, the "SYNDICATION AGENT"), BANK OF
AMERICA, N.A. (formerly known as NationsBank, N.A.), individually as a Bank
("BOFA") and as documentation agent for the other Banks (in such capacity
together with any other Person who becomes the documentation agent, the
"DOCUMENTATION AGENT"; and together with the Administrative Agent and the
Syndication Agent, the "AGENTS"), and CREDIT LYONNAIS, individually as a Bank
and Co-Agent, NATIONAL CITY BANK, individually as a Bank and as Co-Agent, and
THE BANK OF NOVA SCOTIA, individually as a Bank and as Co-Agent (collectively,
the "CO-AGENTS"), and is made with reference to that certain Third Amended and
Restated Credit Agreement dated as of December 14, 1998, by and among the
Company, the Guarantors, the Banks, the Agents and the Co-Agents, as amended by
that certain First Amendment dated as of January 14, 1999, and that certain
Second Amendment dated as of August 18, 1999 (as so amended, the "CREDIT
AGREEMENT"), and to other Loan Documents. Capitalized terms used herein without
definition shall have the same meanings herein as set forth in the Credit
Agreement, as amended hereby (the "AMENDED CREDIT AGREEMENT").

                                    RECITALS

      WHEREAS, the Company has advised the Banks that certain Events of Default
will arise on August 14, 2000 as a result of the Company's failure to comply
with certain financial covenants contained in the Credit Agreement with respect
to the fiscal quarter of the Company ended June 30, 2000;

      WHEREAS, the Banks have advised the Company that they are willing to waive
such Events of Default only if the Company, the Credit Support Parties and the
Guarantors accept the amendments to the Credit Agreement set forth herein, which
amendments include, without limitation, (i) the revision of certain financial
covenants and (ii) the addition of an event of default

                                      -1-
<PAGE>
that occurs if the Company makes scheduled principal payments against its
subordinated indebtedness at any time that the Company is not in compliance with
the financial covenants currently set forth in the Credit Agreement;

      NOW, THEREFORE, in consideration of the premises and the agreements,
provisions and covenants herein contained, the parties hereto agree as follows:

      SECTION 1.  AMENDMENT TO THE CREDIT AGREEMENT

      1.1   AMENDMENTS TO SECTION 1.1: DEFINITIONS.

            The definition of "EBITDA" is hereby deleted in its entirety and the
following is substituted therefor:

            ""EBITDA" means, for any period, the consolidated pre-tax income for
            such period, plus the aggregate amount which was deducted for such
            period in determining such consolidated, pre-tax income in respect
            of Interest Expense (including amortization of debt discount,
            imputed interest and capitalized interest), depreciation and
            amortization, provided, the calculations of EBITDA after the
            acquisition of assets or entities permitted under Section 8.5(d)
            shall include pro forma adjustments consistent with the regulations
            and practices of the United States Securities and Exchange
            Commission (whether or not applicable) to account for such acquired
            entity's historical EBITDA for the relevant period or similar
            adjustments in the case of an asset acquisition. For the second
            fiscal quarter of 2000, (and only for the second fiscal quarter of
            2000) an amount, not in excess of $5,500,000, of non-cash unusual
            charges incurred during the second fiscal quarter of 2000 may be
            added back to determine EBITDA."

            The definition of "Financial Compliance" is added in proper
alphabetical order to read as follows:

            ""FINANCIAL COMPLIANCE" means that the Company is in compliance with
            the following financial standards and has delivered the compliance
            certificate in accordance with SECTION 7.1(D) evidencing such
            compliance for the most recent period:

                  (1) The Company will not as of the last day of any fiscal
            quarter permit the ratio of its total Funded Senior Debt on such day
            to EBITDA for the rolling four (4) quarters then ended to be greater
            than 2.50 to 1.00 at any time during the term hereof.

                                      -2-
<PAGE>
                  (2) The Company will not as of the last day of any fiscal
            quarter permit the ratio of (i) its Total Funded Debt on such day to
            (ii) EBITDA for the four consecutive fiscal quarters then ended to
            be greater than 3.50 to 1.00 at any time during the term hereof.

                  (3) The Company will not permit as of the last day of any
            fiscal quarter the ratio of EBITDA for the four consecutive fiscal
            quarters ended on such day to cash Interest Expense for such period
            to be less than 4.00 to 1.00. This interest coverage ratio shall be
            calculated on a rolling four quarter basis.

            The definition of "Margin" is hereby amended by deleting the grid
contained in the definition of "Margin" and substituting the following therefor:

-------------------------------------------------------------------------------
 TOTAL FUNDED DEBT/EBITDA       EURODOLLAR RATE           ALTERNATE BASE
          RATIO                     ADVANCE                RATE ADVANCE
-------------------------------------------------------------------------------
greater than or equal to 3.50       3.000 %                   1.750 %
-------------------------------------------------------------------------------
greater than or equal to 3.00
  but less than 3.50                2.750 %                   1.500 %
-------------------------------------------------------------------------------
greater than or equal to 2.50
  but less than 3.00                2.250 %                   1.000 %
-------------------------------------------------------------------------------
greater than or equal to 2.00
  but less than 2.50                2.000 %                   0.750 %
-------------------------------------------------------------------------------
greater than or equal to 1.50
  but less than 2.00                1.750 %                   0.500 %
-------------------------------------------------------------------------------
greater than or equal to 1.00
  but less than 1.50                1.500 %                   0.250 %
-------------------------------------------------------------------------------
less than 1.00                      1.250 %                   0.250 %
-------------------------------------------------------------------------------

      1.2   AMENDMENT TO SECTION 4.1: FEES.

            Section 4.1(a) of the Credit Agreement is hereby amended by deleting
the grid contained in Section 4.1(a) and substituting the following therefor:

                FUNDED DEBT/EBITDA         COMMITMENT FEE RATE
            -------------------------------------------------------

            greater than or equal to 3.5x           50
            greater than or equal to 3.0x
              and less than 3.5x                    50
            greater than or equal to 2.5x
              and less than 3.0x                    50
            greater than or equal to 2.0x
              and less than 2.5x                  37.5
            greater than or equal to 1.5x
              and less than 2.0x                  37.5
            greater than or equal to 1.0x
              and less than 1.5x                  37.5
            less than 1.0x                          25

                                      -3-
<PAGE>
      1.3   AMENDMENT TO SECTION 8.5: INVESTMENTS.

            Section 8.5(d) of the Credit Agreement is hereby amended by deleting
the reference to "$15,000,000" contained therein and substituting "$5,000,000"
therefor.

      1.4   AMENDMENT TO SECTION 8.8: CHANGE OF CERTAIN INDEBTEDNESS.

            Section 8.8 is hereby deleted in its entirety and the following
substituted therefor:

            "The Company will not, and will not permit any of its Subsidiaries,
            after the occurrence and during the continuance of any Event of
            Default or at any time the Company is not in Financial Compliance,
            to make any voluntary prepayments of principal or interest on any
            other of the Company's Indebtedness."

      1.5   AMENDMENT TO SECTION 8.10: FUNDED SENIOR DEBT TO EBITDA RATIO.

            Section 8.10 of the Credit Agreement is deleted in its entirety and
the following is substituted therefor:

            "The Company will not, as of the last day of any fiscal quarter,
            permit the ratio of its total Funded Senior Debt on such day to
            EBITDA for the four consecutive fiscal quarters then ended to exceed
            the amounts set forth below:

                     DATE(S)                 RATIO
                     -------                 -----
                     09/30/00                3.30x
               12/31/00 - 03/31/01           3.15x
             06/30/01 and thereafter         3.00x

      For purposes of calculating the ratio in this Section 8.10, the
      calculation of Funded Senior Debt after the acquisition of assets or
      entities permitted under this Agreement shall

                                      -4-
<PAGE>
      include adjustments to account for the total Funded Senior Debt of or
      applicable to such acquired assets or entities during the relevant period.

      1.6   AMENDMENT TO SECTION 8.11: TOTAL FUNDED DEBT TO EBITDA RATIO.

            Section 8.11 of the Credit Agreement is deleted in its entirety and
the following is substituted therefor:

            "The Company will not, as of the last day of any fiscal quarter,
            permit the ratio of (i) its Total Funded Debt on such day to (ii)
            EBITDA for the four consecutive fiscal quarters then ended to exceed
            the amounts set forth below:

                     DATE(S)                 RATIO
                     -------                 -----
                     09/30/00                4.00x

               12/31/00 - 03/31/01           3.90x

             06/30/01 and thereafter         3.65x

      For purposes of calculating the ratios in SECTIONS 8.10 and 8.11, the
      calculations of Total Funded Debt and Funded Senior Debt after the
      acquisition of assets or entities permitted under this Agreement shall
      include adjustments to account for such acquired entity's Total Funded
      Debt immediately prior to the acquisition and Funded Senior Debt for the
      relevant period."

      1.7   AMENDMENT TO SECTION 8.14: INTEREST COVERAGE RATIO.

            Section 8.14 of the Credit Agreement is deleted in its entirety and
the following is substituted therefor:

            "The Company will not, as of the last day of any fiscal quarter,
            permit the ratio of EBITDA for the four consecutive fiscal quarters
            then ended to cash Interest Expense for such period to be less than
            the amounts set forth below:

                     DATE(S)                 RATIO
                     -------                 -----
                     09/30/00                3.20x
                     12/31/00                3.00x
                     03/31/01                2.80x
             06/30/01 and thereafter         2.90x

                                      -5-
<PAGE>
      1.8   ADDITION OF SECTION 8.15: MINIMUM EBITDA.

            A new Section 8.15 is hereby added to read as follows:

            "Section 8.15 MINIMUM EBITDA. The Company will not, as of the last
            day of any fiscal quarter specified in the table below, permit its
            EBITDA for the three (3) months then ended to be less than the
            amounts set forth below:

                     DATE(S)            QUARTERLY EBITDA
                     -------            ----------------
                     09/30/00             $22,000,000
                     12/31/00             $21,500,000
                     03/31/01             $15,000,000
                     06/30/01             $18,500,000
                     09/30/01             $23,500,000

      1.9   AMENDMENTS TO SECTION 10.1:  EVENTS OF DEFAULT.

            Section 10.1(d) of the Credit Agreement is hereby amended by adding
the following language at the end of Section 10.1(d):

            ", provided that, the failure of the Company to make the Restricted
            Subordinated Debt Payments proscribed by SECTION 10.1(J) shall not
            constitute an Event of Default"

            A new Section 10.1(j) is hereby added to read as follows:

            "(j) During any period in which the Company is not in Financial
            Compliance, the Company shall make any Restricted Subordinated Debt
            Payments which (but for the operation of this SECTION 10.1(J), would
            be permitted by SECTION 8.6(C), PROVIDED, the Company's $1,600,000
            payment of scheduled third fiscal quarter of 2000 Subordinated Debt
            made on July __, 2000 shall not be an Event of Default hereunder."

      1.10  WAIVER OF EVENTS OF DEFAULT

                                      -6-
<PAGE>
            The provisions of Section 8.6(ii)(c) are hereby waived by the Banks,
retroactively to the extent required to avoid an Event of Default under the
Credit Agreement caused solely by the Borrowers making payments on Subordinated
Debt during the continuation of an Event of Default during the second fiscal
quarter of 2000. The provisions of Section 8.10 are hereby waived by the Banks,
retroactively to the extent required to avoid an Event of Default under the
Credit Agreement caused solely by the Borrowers exceeding the maximum Funded
Senior Debt to EBITDA Ratio during the second fiscal quarter of 2000. This
limited waiver shall not constitute a waiver of any other Default or Event of
Default except as expressly set forth herein.

      SECTION 2.  CONDITIONS TO EFFECTIVENESS

      Section 1 of this Amendment shall become effective only upon the prior or
concurrent satisfaction of all of the following conditions precedent (the date
of satisfaction of such conditions being referred to herein as the "AMENDMENT
EFFECTIVE DATE"):

      A. On or before the Amendment Effective Date, the Company shall deliver to
the Banks (or to the Agents for the Banks) the following, each, unless otherwise
noted, dated the Amendment Effective Date:

            1. A certificate of the secretary or an assistant secretary of the
Company and of the Guarantors certifying: (i) that the resolutions of the Board
of Directors of the Company and of the Guarantors approving and authorizing the
execution, delivery, and performance of the Amended Credit Agreement and
amendments thereto delivered on the Effective Date, are in full force and effect
and have not been amended, supplemented or otherwise modified since December 14,
1998 and (ii) the signature and incumbency of the officers of each of the
Company and of the Guarantors who are authorized to sign on behalf of the
Company or such Guarantor.

            2. Counterparts of this Amendment executed by the Majority Banks and
each of the other parties hereto.

            3. Payment to each of the Banks approving this Amendment, subject to
Majority Bank approval, of an amendment fee equal to fifteen one hundredths of
one percent (0.15%) of such Bank's Commitment if approved by such Bank prior to
5:00 P.M. (CST) August 9, 2000. Payment to each of the Banks approving this
Amendment, subject to Majority Bank approval, of an amendment fee equal to
twelve and one-half one hundredths of one percent (0.125%) of such Bank's
Commitment if approved by such Bank prior to 5:00 P.M. (CST) August 11, 2000.

      B. On or before the Amendment Effective Date, all corporate and other
proceedings taken or to be taken in connection with the transactions
contemplated hereby and all documents incidental thereto not previously found
acceptable by the Agents, acting on behalf of the Banks, and

                                      -7-
<PAGE>
their counsel shall be satisfactory in form and substance to the Agents and such
counsel, and the Agents and such counsel shall have received all such
counterpart originals or certified copies of such documents as the Agents may
reasonably request.

      SECTION 3.  REPRESENTATIONS AND WARRANTIES

      In order to induce the Banks to enter into this Amendment and to amend the
Credit Agreement in the manner provided herein, the Company and each Guarantor
party hereto represents and warrants to each Bank that the following statements
are true, correct and complete as to itself:

      A. CORPORATE POWER AND AUTHORITY. The Company and each Guarantor party
hereto has all requisite corporate power and authority to enter into this
Amendment and to carry out the transactions contemplated hereby and the Company
and each Guarantor party hereto has all requisite corporate power and authority
to carry out the transactions contemplated by, and perform its obligations
under, the Amended Credit Agreement.

      B. AUTHORIZATION OF AGREEMENTS. The execution and delivery of this
Amendment and the performance of the Amended Credit Agreement have been duly
authorized by all necessary corporate action on the part of the Company and each
Guarantor party hereto, as the case may be.

      C. NO CONFLICT. The execution and delivery by the Company and each
Guarantor party hereto of this Amendment and the performance by the Company and
each Guarantor of this Amendment and the performance by the Company of the
Amended Credit Agreement do not and will not (i) violate any provision of any
law or any governmental rule or regulation applicable to the Company or any of
its Subsidiaries, the Certificate or Articles of Incorporation or Bylaws of the
Company or any of its Subsidiaries or any order, judgment or decree of any court
or other agency of government binding on the Company or any of its Subsidiaries,
(ii) conflict with, result in a breach of or constitute (with due notice or
lapse of time or both) a default under any material agreement (other than
failure to pay the notes evidencing the Subordinated Debt in acordance with this
Amendment) to which the Company or any of its Subsidiaries is a party or by
which it is bound or to which it is subject, (iii) result in or require the
creation or imposition of any Lien upon any of the properties or assets of the
Company or any of its Subsidiaries (other than any Liens created under any of
the Loan Documents in favor of the Agents on behalf of the Banks), or (iv)
require any approval of stockholders or any approval or consent of any Person
under any material agreement to which the Company or any of its Subsidiaries is
a party or by which it is bound or to which it is subject.

      D. GOVERNMENTAL CONSENTS. The execution and delivery by the Company and
each Guarantor party hereto of this Amendment and the performance by the Company
and each Guarantor of this Amendment and the performance by the Company and each
Guarantor of the Amended Credit

                                      -8-
<PAGE>
Agreement do not and will not require any registration with, consent or approval
of, or notice to, or other action to, with or by, any federal, state or other
governmental authority or regulatory body.

      E. BINDING OBLIGATION. This Amendment has been duly executed and delivered
by the Company and each Guarantor party hereto and this Amendment and the
Amended Credit Agreement are the legally valid and binding obligations of the
Company and each Guarantor, enforceable against the Company and each Guarantor
in accordance with their respective terms, except as may be limited by
bankruptcy, insolvency, reorganization, moratorium or similar laws relating to
or limiting creditors' rights generally or by equitable principles relating to
enforceability.

      F. INCORPORATION OF REPRESENTATIONS AND WARRANTIES FROM AMENDED CREDIT
AGREEMENT. The representations and warranties contained in Article VI of the
Amended Credit Agreement are and will be true, correct and complete in all
material respects on and as of the Amendment Effective Date to the same extent
as though made on and as of that date, except (i) to the extent such
representations and warranties specifically relate to an earlier date, in which
case they were true, correct and complete in all material respects on and as of
such earlier date, and (ii) to the extent such representations and warranties
relate to a default of any Subordinated Debt resulting from a failure to pay the
notes evidencing such Subordinated Debt in accordance with this amendment
resulting from the Company not being in Financial Compliance.

      G. ABSENCE OF DEFAULT. No event has occurred and is continuing or will
result from the consummation of the transactions contemplated by this Amendment
that would, after giving effect to this Amendment, constitute an Event of
Default or a Default.

      SECTION 4.  ACKNOWLEDGMENT AND CONSENT

      The Company is a party to certain Collateral Documents pursuant to which
the Company has created Liens in favor of the Agents on certain Collateral to
secure the Obligations. Each of the Guarantors party hereto is a party to
certain Collateral Documents and the Guaranty, pursuant to which each such
Guarantor has (i) guarantied the Obligations and (ii) created Liens in favor of
the Administrative Agent on certain Collateral to secure the Guaranteed
Obligations of such Guarantor under the Guaranty. The Guarantors party hereto
are collectively referred to herein as the "CREDIT SUPPORT PARTIES", and the
Collateral Documents and the Guaranty are collectively referred to herein as the
"CREDIT SUPPORT DOCUMENTS".

      Each Credit Support Party hereby acknowledges that it has reviewed the
terms and provisions of the Credit Agreement, the Collateral Documents and the
Guaranty and this Amendment and consents to the further amendment of the Credit
Agreement effected pursuant to this Amendment. Each Credit Support Party hereby
confirms that each Credit Support Document to which it is a party or otherwise
bound and all Collateral encumbered thereby will continue to guaranty or secure,
as the case may be, to the fullest extent possible the payment and performance

                                      -9-
<PAGE>
of all "Obligations," "Guarantied Obligations" and "Secured Obligations," as the
case may be (in each case as such terms are defined in the applicable Credit
Support Document), including without limitation the payment and performance of
all such "Obligations," "Guarantied Obligations" or "Secured Obligations," as
the case may be, in respect of the Obligations of the Company now or hereafter
existing under or in respect of the Amended Credit Agreement and the Notes.

      Each Credit Support Party acknowledges and agrees that any of the Credit
Support Documents to which it is a party or otherwise bound shall continue in
full force and effect and that all of its obligations thereunder shall be valid
and enforceable and shall not be impaired or limited by the execution or
effectiveness of this Amendment. Each Credit Support Party represents and
warrants that all representations and warranties contained in the Amended Credit
Agreement and the other Credit Support Documents to which it is a party or
otherwise bound are true, correct and complete in all material respects on and
as of the Amendment Effective Date to the same extent as though made on and as
of that date, except (i) to the extent such representations and warranties
specifically relate to an earlier date, in which case they were true, correct
and complete in all material respects on and as of such earlier date, and (ii)
to the extent such representations and warranties relate to a default of any
Subordinated Debt resulting from a failure to pay the notes evidencing such
Subordinated Debt in accordance with this amendment resulting from the Company
not being in Financial Compliance.

      Each Credit Support Party acknowledges and agrees that (i) notwithstanding
the conditions to effectiveness set forth in this Amendment, such Credit Support
Party is not required by the terms of the Credit Agreement or any other Loan
Document to consent to the amendments to the Credit Agreement effected pursuant
to this Amendment and (ii) nothing in the Amended Credit Agreement, this
Amendment or any other Loan Document shall be deemed to require the consent of
such Credit Support Party to any future amendments to the Amended Credit
Agreement.

      SECTION 5.  MISCELLANEOUS

      A. REFERENCE TO AND EFFECT ON THE AMENDED CREDIT AGREEMENT AND THE OTHER
LOAN DOCUMENTS.

            (i) On and after the Amendment Effective Date, each reference in the
      Credit Agreement to "this Agreement", "hereunder", "hereof", "herein" or
      words of like import referring to the Credit Agreement, and each reference
      in the other Loan Documents to the "Credit Agreement", "thereunder",
      "thereof" or words of like import referring to the Credit Agreement shall
      mean and be a reference to the Amended Credit Agreement.

            (ii) Except as specifically amended by this Amendment, the Credit
      Agreement and the other Loan Documents shall remain in full force and
      effect and are hereby ratified and confirmed.

                                      -10-
<PAGE>
            (iii) The execution, delivery and performance of this Amendment
      shall not, except as expressly provided herein, constitute a waiver of any
      provision of, or operate as a waiver of any right, power or remedy of any
      Agent or any Bank under, the Credit Agreement or any of the other Loan
      Documents.

      B. FEES AND EXPENSES. Company acknowledges that all reasonable costs, fees
and expenses as described in Section 12.4 of the Credit Agreement incurred by
the Agents and its counsel with respect to this Amendment and the documents and
transactions contemplated hereby shall be for the account of the Company.

      C. HEADINGS. Section and subsection headings in this Amendment are
included herein for convenience of reference only and shall not constitute a
part of this Amendment for any other purpose or be given any substantive effect.

      D. APPLICABLE LAW. THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE
PARTIES HEREUNDER SHALL BE GOVERNED BY, AND SHALL BE CONSTRUED AND ENFORCED IN
ACCORDANCE WITH, THE INTERNAL LAWS OF THE STATE OF NEW YORK (INCLUDING WITHOUT
LIMITATION SECTION 5-1401 OF THE GENERAL OBLIGATIONS LAW OF THE STATE OF NEW
YORK), WITHOUT REGARD TO CONFLICTS OF LAWS PRINCIPLES.

      E. COUNTERPARTS; EFFECTIVENESS. This Amendment may be executed in any
number of counterparts and by different parties hereto in separate counterparts,
each of which when so executed and delivered shall be deemed an original, but
all such counterparts together shall constitute but one and the same instrument;
signature pages may be detached from multiple separate counterparts and attached
to a single counterpart so that all signature pages are physically attached to
the same document. This Amendment (other than the provisions of Section 1, which
shall become effective upon the satisfaction of each of the conditions set forth
in Section 2) shall become effective upon the execution of a counterpart hereof
by the Company, the Credit Support Parties, the Guarantors and the Majority
Banks and receipt by the Company and the Agents of written or telephonic
notification of such execution and authorization of delivery of such
counterpart.

                  [Remainder of page intentionally left blank]

                                      -11-
<PAGE>
      IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed by their respective officers thereunto duly authorized as of the date
first above written.

                                    COMPANY:

                                    COMFORT SYSTEMS USA, INC.

                                    By: ________________________________________
                                            J. Gordon Beittenmiller
                                            Senior Vice President and
                                            Chief Financial Officer
<PAGE>
                              CREDIT SUPPORT PARTIES AND GUARANTORS:

                                    ADAMS MECHANICAL SERVICES, INC.
                                    ACCURATE AIR SYSTEMS, INC.
                                    AIR POWER SYSTEMS, INC.
                                    ALLSTATE MECHANICAL, INC.
                                    ATLAS AIR CONDITIONING COMPANY
                                    ATLAS COMFORT SERVICES USA, INC.
                                    BATCHELOR'S MECHANICAL CONTRACTORS, INC.
                                    BCM CONTROLS CORPORATION
                                    CEL, INC.
                                    CONTRACT SERVICE, INC.
                                    DESIGN MECHANICAL INCORPORATED
                                    DYNASTAR, INC.
                                    EASTERN HEATING & COOLING, INC.
                                    EASTERN REFRIGERATION CO., INC.
                                    EDS, INC.
                                    F&G MECHANICAL CORPORATION
                                    FRED HAYES MECHANICAL CONTRACTORS, INC.
                                    FREEWAY HEATING & AIR CONDITIONING, INC.
                                    GMS AIR CONDITIONING, INC.
                                    HELM CORPORATION
                                    HILLCREST SHEET METAL, INC.
                                    JAMES AIR CONDITIONING ENTERPRISES, INC.
                                    KUEMPEL SERVICE, INC.
                                    LAWRENCE SERVICE, INC.
                                    LOWRIE ELECTRIC CO., INC.
                                    MANDELL MECHANICAL CORPORATION
                                    MARTIN HEATING, INC.
                                    MEADOWLANDS FIRE PROTECTION CORP.
                                    MECHANICAL SERVICE GROUP, INC.
                                    MJ MECHANICAL SERVICES, INC.
                                    NOGLE & BLACK MECHANICAL, INC.
                                    NORTH JERSEY MECHANICAL CONTRACTORS, INC.
<PAGE>
                                    OK SHEET METAL & AIR CONDITIONING, INC.
                                    QUALITY AIR HEATING & COOLING, INC.
                                    RHC ACQUISITION CORP.
                                    RIVER CITY MECHANICAL, INC.
                                    SALMON & ALDER, INC.
                                    SEASONAIR, INC.
                                    S&K AIR CONDITIONING CO., INC.
                                    S.M. LAWRENCE COMPANY, INC.
                                    STANDARD HEATING & AIR CONDITIONING COMPANY
                                    TECH HEATING AND AIR CONDITIONING, INC.
                                    TECH MECHANICAL, INC.
                                    TEMP-RIGHT SERVICE, INC.
                                    TRI-CITY MECHANICAL, INC.
                                    TROOST SERVICE CO.
                                    WALKER-J-WALKER, INC.
                                    WESTERN BUILDING SERVICES, INC.

                                    By: ________________________________________
                                                  J. Gordon Beittenmiller
                                                  Vice President
<PAGE>
AMOUNT OF COMMITMENT:            ADMINISTRATIVE AGENT/BANK:

$45,000,000.00                   BANK ONE, TEXAS, N.A.,
                                 AS ADMINISTRATIVE AGENT AND INDIVIDUALLY
                                 AS A BANK

                                 By: ___________________________________________
                                 Name: _________________________________________
                                 Title: ________________________________________

AMOUNT OF COMMITMENT:            SYNDICATION AGENT/BANK:

$35,000,000.00                   BANKERS TRUST COMPANY,
                                 AS SYNDICATION AGENT AND INDIVIDUALLY AS A BANK

                                 By: ___________________________________________
                                 Name: _________________________________________
                                 Title: ________________________________________

AMOUNT OF COMMITMENT:            DOCUMENTATION AGENT/BANK:

$42,500,000.00                   BANK OF AMERICA, N.A. (FORMERLY KNOWN AS
                                 NATIONSBANK, N.A.), AS DOCUMENTATION AGENT
                                 AND INDIVIDUALLY, AS A BANK

                                 By: ___________________________________________
                                 Name: _________________________________________
                                 Title: ________________________________________
<PAGE>
AMOUNT OF COMMITMENT:            CO-AGENT/BANK:

$25,000,000.00                   CREDIT LYONNAIS, NEW YORK BRANCH,
                                 AS CO-AGENT AND INDIVIDUALLY, AS A BANK

                                 By: ___________________________________________
                                 Name: _________________________________________
                                 Title: ________________________________________

AMOUNT OF COMMITMENT:            CO-AGENT/BANK:

$25,000,000.00                   NATIONAL CITY BANK,
                                 AS CO-AGENT AND INDIVIDUALLY, AS A BANK

                                 By: ___________________________________________
                                 Name: _________________________________________
                                 Title: ________________________________________

AMOUNT OF COMMITMENT:            CO-AGENT/BANK:

$25,000,000.00                   THE BANK OF NOVA SCOTIA, AS CO-AGENT AND
                                 INDIVIDUALLY, AS A BANK

                                 By: ___________________________________________
                                 Name: _________________________________________
                                 Title: ________________________________________
<PAGE>
AMOUNT OF COMMITMENT:            BANK:

$20,000,000.00                   UNION BANK OF CALIFORNIA, N.A.

                                 By: ___________________________________________
                                 Name: _________________________________________
                                 Title: ________________________________________

AMOUNT OF COMMITMENT:            BANK:

$15,000,000.00                   COMERICA BANK

                                 By: ___________________________________________
                                 Name: _________________________________________
                                 Title: ________________________________________

AMOUNT OF COMMITMENT:            BANK:

$5,000,000.00                    BANK POLSKA, KASA OPIEKI S.A., PEKOA S.A.
                                 GROUP, NEW YORK BRANCH

                                 By: ___________________________________________
                                 Name: _________________________________________
                                 Title: ________________________________________
<PAGE>
AMOUNT OF COMMITMENT:            BANK:

$30,000,000.00                   FIRSTAR BANK, NATIONAL ASSOCIATION

                                 By: ___________________________________________
                                 Name: _________________________________________
                                 Title: ________________________________________

AMOUNT OF COMMITMENT:            BANK:

$20,000,000.00                   LASALLE BANK NATIONAL ASSOCIATION

                                 By: ___________________________________________
                                 Name: _________________________________________
                                 Title: ________________________________________

AMOUNT OF COMMITMENT:            BANK:

$12,500,000.00                   GENERAL ELECTRIC CAPITAL
                                 CORPORATION

                                 By: ___________________________________________
                                 Name: _________________________________________
                                 Title: ________________________________________

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}], [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}]]