<PAGE>   1
                                                                   EXHIBIT 10.11

                                AMENDMENT TO THE
                              SERVICE EXPERTS, INC.
                       1997 NONQUALIFIED STOCK OPTION PLAN

         THIS AMENDMENT to the Service Experts, Inc. 1997 Nonqualified Stock
Option Plan (the "Plan") is made by Service Experts, Inc. (the "Company"), to be
effective on October 23, 1998.

                                    RECITALS:

         WHEREAS, the Plan was established by the Company by action of its board
of directors on April 3, 1998;

         WHEREAS, the Company desires to amend the Plan to allow the grant of
cash awards and loans in connection with the grant or exercise of Options;

         WHEREAS, the Company desires to amend the Plan to clarify the rights of
certain employees upon a change in the control of the Company; and

         WHEREAS, the Company desires to further amend the Plan to modify the
effect of a change in control on the awards that are granted under the Plan.

         NOW, THEREFORE, pursuant to action of the board of directors of the
Company taken on October 23, 1998, the Plan is amended as follows, to be
effective October 23, 1998:

1. A new Section 4.4 is added to the Plan as follows:

                  4.4 Guarantees and Loans. The Company is hereby authorized to
         guarantee and make loans to a Participant to enable him to exercise an
         Option. Any loan made or guaranteed herein shall be in such amount as
         determined by the Committee but shall not exceed the exercise price of
         the Options being exercised by the Participant. Any loans made or
         guaranteed shall be with full recourse against the Participant, shall
         be secured by the Stock received from exercise of the related Option,
         shall provide for a market rate of interest, and shall contain such
         other terms and conditions as are acceptable to the Committee. The
         determination of whether loans are to be made or guaranteed shall be
         made by the Committee.

2. A new Section 4.5 is added to the Plan as follows:

                  4.5 Other Compensation. Nothing contained in this Plan shall
         prevent the Board from adopting other or additional compensation
         arrangements, subject to shareholder approval if such approval is
         required, and such arrangements may be either generally applicable or
         applicable only in specific cases.


<PAGE>   2


3. Section 8.3 is restated as follows:

                  8.3 Effect of Certain Transactions. The provisions of this
         Section 8.3 shall apply to the extent that an Agreement does not
         otherwise expressly address the matters contained herein.

                           (a) If the Company experiences an event which results
                  in a "Change in Control," as defined in Section 8.3(b), then,
                  whether or not the vesting requirements set forth in any
                  Agreement have been satisfied, (i) all shares of Restricted
                  Stock that are outstanding at the time of the Change in
                  Control shall become fully vested immediately prior to the
                  Change in Control event, and (ii) all Options that are
                  outstanding at the time of the Change in Control shall become
                  fully vested and exercisable immediately prior to the Change
                  in Control event.

                           (b) A Change in Control will be deemed to have
                  occurred for purposes hereof, upon a merger, consolidation,
                  acquisition of property or stock, separation, reorganization
                  or liquidation of the Company, as a result of which the
                  stockholders of the Company receive cash, stock or other
                  property in exchange for their shares of Stock (but not a
                  public offering of Stock by the Company), and the Company is
                  not the surviving entity.

                           (c) Upon a Change in Control, all Options that are
                  held by the Participant immediately after the Change in
                  Control shall be assumed by the entity which is the survivor
                  of the transaction, or converted into options to purchase the
                  common stock of the surviving entity, in a transaction to
                  which section 424(a) of the Code applies.

                           (d) Notwithstanding the foregoing, a portion of the
                  acceleration of vesting described in this Section shall not
                  occur with respect to an Award to the extent such acceleration
                  of vesting would cause the Participant or holder of such Award
                  to realize less income, net of taxes, after deducting the
                  amount of excise taxes that would be imposed pursuant to
                  section 4999 of the Code, than if accelerated vesting of that
                  portion of the Award did not occur.

                           (e) In the event of any Change in Control in which
                  shares of Stock are purchased for cash in a tender offer or
                  are to be converted into cash in a merger, then, unless the
                  Committee otherwise determines, each Option (other than an
                  Option granted within the last six months held by a person
                  subject to Section 16(b) of the Exchange Act) shall be
                  converted into a fully exercisable right to receive an amount
                  in cash per share subject to such Option equal to (A) in the
                  case of a tender offer or merger, the excess, if any, of the
                  price paid in such tender offer or merger over the exercise
                  price of such Option and (B) in the case of conversion, the
                  excess, if any, of the highest market price of the Stock on
                  the date of conversion over the exercise price of such Option;
                  provided, however, that any acceleration of the right to
                  exercise an Option that occurs under this Section 8.3(e) shall
                  be limited in the manner described in Section 8.3(d).






                                      2
<PAGE>   3

         IN WITNESS WHEREOF, the Company, acting by and through the undersigned
authorized officer, has executed this instrument this the 23rd day of October,
1998, but to be effective on the date first written above.

                                         SERVICE EXPERTS, INC.

                                    By:  /s/ Anthony M. Schofield 
                                         ---------------------------------------
                                    Its: Chief Financial Officer, Secretary and
                                         Treasurer









                                       3