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)) and internal control over
financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f))
for the small business issuer and have:

       a) designed such disclosure controls and procedures to provide 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) designed such internal control over financial reporting, or caused
       such internal control over financial reporting to be designed under our
       supervision, to provide reasonable assurance regarding the reliability of
       financial reporting and the preparation of financial statements for
       external purposes in accordance with generally accepted accounting
       principles;

       c) evaluated the overall effectiveness of the small business issuer's
       disclosure controls and procedures to provide that material information
       relating to the registrant, as of the end of the period covered by this
       report based on such evaluation; and

       d) 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; and

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: August 10, 2006         BY:  /s/  JOHN F. FERRARO
                                          ----------------------
                                          John F. Ferraro
                                          Treasurer and Chief Financial Officer