EXHIBIT 31(B)
                                                                   -------------

                                  CERTIFICATION
   PURSUANT TO RULES 13A-15 AND 15D-15 OF THE SECURITIES EXCHANGE ACT OF 1934

I, ROBERT I. LIEBERMAN, Chief Financial Officer of Thermodynetics, Inc., certify
that:

1. I have reviewed this quarterly report on Form 10-QSB of THERMODYNETICS, INC.;

2. Based on my knowledge, this report does not contain any untrue statement of a
material fact or omit to state a material fact  necessary to make the statements
made, in light of the  circumstances  under which such statements were made, not
misleading with respect to the period covered by this report;

3.  Based  on my  knowledge,  the  financial  statements,  and  other  financial
information included in this report, fairly present in all material respects the
financial condition,  results of operations and cash flows of the small business
issuer as of, and for, the periods presented in this report;

4. The small business  issuer's other certifying  officers and I are responsible
for establishing and maintaining  disclosure controls and procedures (as defined
in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the small business issuer and
have:

         a) designed such  disclosure  controls and  procedures,  or caused such
         disclosure   controls  and   procedures   to  be  designed   under  our
         supervision,  to ensure that material information relating to the small
         business issuer, including its consolidated subsidiaries, is made known
         to us by others within those entities,  particularly  during the period
         in which this report is being prepared;

         b) evaluated the overall  effectiveness of the small business  issuer's
         disclosure  controls and  procedures  and  presented in this report our
         conclusions  about the  effectiveness  of the  disclosure  controls and
         procedures, as of the end of the period covered by this report based on
         such evaluation; and

         c) disclosed in this report any change in the small  business  issuer's
         internal  control over  financial  reporting  that occurred  during the
         small business  issuer's most recent fiscal quarter (the small business
         issuer's  fourth fiscal  quarter in the case of an annual  report) that
         has materially affected,  or is reasonably likely to materially affect,
         the small business issuer's internal control over financial reporting;

5. The small business  issuer's other certifying  officers and I have disclosed,
based on our knowledge and our most recent  evaluation of internal  control over
financial  reporting,  to the small  business  issuer's  auditors  and the small
business issuer's board of directors:

         a) all significant  deficiencies and material  weaknesses in the design
         or operation of internal  control over  financial  reporting  which are
         reasonably  likely to  adversely  affect  the small  business  issuer's
         ability to record, process, summarize and report financial information;
         and

         b) any fraud,  whether or not  material,  that  involves  management or
         other  employees  who have a  significant  role in the  small  business
         issuer's internal control over financial reporting.


             Date: February 10, 2004   By: /s/  Robert I. Lieberman
                                          ---------------------------
                                           Robert I. Lieberman
                                           Treasurer and Chief Financial Officer