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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Arf4zCWhvkYqHN8/crNAooifEwVSvEFnsmJIi+xIn3cQccdwvDOIsSvHiMFmpFVE
 txtazsg/iHWWFq6Pz/G13A==

<SEC-DOCUMENT>0000930413-07-007966.txt : 20071016
<SEC-HEADER>0000930413-07-007966.hdr.sgml : 20071016
<ACCEPTANCE-DATETIME>20071016144725
ACCESSION NUMBER:		0000930413-07-007966
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20071011
FILED AS OF DATE:		20071016
DATE AS OF CHANGE:		20071016

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			THERMODYNETICS INC
		CENTRAL INDEX KEY:			0000351902
		STANDARD INDUSTRIAL CLASSIFICATION:	MISCELLANEOUS FABRICATED METAL PRODUCTS [3490]
		IRS NUMBER:				061042505
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		651 DAY HILL RD
		STREET 2:		.
		CITY:			WINDSOR
		STATE:			CT
		ZIP:			06095
		BUSINESS PHONE:		2036832005

	MAIL ADDRESS:	
		STREET 1:		651 DAY HILL ROAD
		STREET 2:		.
		CITY:			WINDSOR
		STATE:			CT
		ZIP:			06095

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	THERMO KINETICS INC
		DATE OF NAME CHANGE:	19810607

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Thermodynetics, Inc. 401(k) Profit-Sharing Plan
		CENTRAL INDEX KEY:			0001381080
		STATE OF INCORPORATION:			CT
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-10707
		FILM NUMBER:		071174001

	BUSINESS ADDRESS:	
		STREET 1:		651 DAY HILL ROAD
		CITY:			WINDSOR
		STATE:			CT
		ZIP:			06095
		BUSINESS PHONE:		860-683-2005 X 204

	MAIL ADDRESS:	
		STREET 1:		651 DAY HILL ROAD
		CITY:			WINDSOR
		STATE:			CT
		ZIP:			06095
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>c50698_ex.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-10-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000351902</issuerCik>
        <issuerName>THERMODYNETICS INC</issuerName>
        <issuerTradingSymbol>TDYT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001381080</rptOwnerCik>
            <rptOwnerName>Thermodynetics, Inc. 401(k) Profit-Sharing Plan</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>651 DAY HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WINDSOR</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06095</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>401(k) Plan of Issuer</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, $.01 par value</value>
            </securityTitle>
            <transactionDate>
                <value>2007-10-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>25000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.75</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>94296</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">1st:  This filing is voluntary since the 401(k) Plan holdings are less than 10% of the outstanding stock of the Issuer.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Robert A. Lerman - Trustee</signatureName>
        <signatureDate>2007-10-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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