EXHIBIT 31(b)

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

I, JOHN F. FERRARO, 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) caused such disclosure controls and procedures to be designed 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 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 audit
committee of 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 controls over financial reporting.


         Date: February 13, 2007             By:      /s/  John F. Ferraro
                                                      ----------------------
                                                      John F. Ferraro
                                                      Treasurer and Chief
                                                      Financial Officer