SUBSCRIPTION AGREEMENT

THE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 OR THE
SECURITIES LAWS OF ANY STATE OR ANY OTHER JURISDICTION. THERE ARE RESTRICTIONS
ON THE TRANSFERABILITY OF THE SECURITIES DESCRIBED HEREIN.
THE PURCHASE OF THE SECURITIES INVOLVES A HIGH DEGREE OF RISK AND SHOULD BE
CONSIDERED ONLY BY PERSONS WHO CAN BEAR THE RISK OF THE LOSS OF THEIR ENTIRE
INVESTMENT.

THIS SUBSCRIPTION AGREEMENT (this “Agreement”), dated as of ___6/24/2015___
(“Effective Date”), is by and among American DG Energy Inc., a Delaware
corporation (the “Company”), and the subscriber identified on the signature
pages hereto (the “Subscriber”).

WHEREAS, the Company and the Subscriber (the “Parties”) are executing and
delivering this Agreement in reliance upon an exemption from securities
registration afforded by the provisions of Section 4(a)(2), Section 4(a)(6)
and/or Regulation D (“Reg. D”) as promulgated by the United States Securities
and Exchange Commission (the “SEC”) under the Securities Act of 1933, as amended
(the “Securities Act”); and

WHEREAS, the parties desire that, upon the terms and subject to the conditions
contained herein, the Company shall issue to the Subscriber, as provided herein,
and the Subscriber accept, in the aggregate, at the Effective Date, 100,000
shares of the Company’s Common Stock (such shares, the “Shares”) in exchange for
the “Purchase Price”. The Purchase Price is in the form of the Subscriber’s
agreement and cooperation in connection with the distribution of assets
contained in a joint venture co-owned by the Subscriber’s company and the
Company.

NOW, THEREFORE, in consideration of the mutual covenants, the revised amended
partnership agreement and other agreements contained in this Agreement, the
Company and the Subscriber hereby agree as follows:

1.    Purchase and Sale of Shares. Subject to the satisfaction (or waiver) of
the conditions set forth in this Agreement, on the Effective Date of this
agreement, the Company shall notify it’s transfer agent to send Shares to the
Subscriber.

2.    Subscribers’ Representations and Warranties. The Subscriber hereby
represents and warrants to and agrees with the Company, only as to such
Subscriber, that:

(a)    Information on Company. The Subscriber has been furnished with or has had
access at the EDGAR website of the SEC to the Company’s Form 10-K for the year
ended December 31, 2014, and all filings subsequently made by the Company with
the SEC (hereinafter referred to collectively as the “Reports”). In addition,
the Subscriber has received in writing from the Company such other information
concerning its operations, financial condition and other matters as the
Subscriber has requested in writing and considered all factors the Subscriber
deems material in deciding on the advisability of investing in the Shares.

(b)    Information on Subscriber. The Subscriber was at the time it was offered
the Shares, is on the date hereof and will be on the Effective Date an
“accredited investor”, as such term is defined in Reg. D promulgated by the SEC
under the Securities Act, is experienced in investments and business matters,
has made investments of a speculative or high risk nature and has purchased
securities of publicly-owned companies in private placements in the past and,
together with its representatives and/or trustee, as applicable, has such
knowledge and experience in financial, tax and other business matters as to
enable the Subscriber to utilize the

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information made available by the Company to evaluate the merits and risks of
and to make an informed investment decision with respect to the proposed
purchase. The Subscriber has the authority and is duly and legally qualified to
purchase and own the Shares. The Subscriber is able to bear the risk of such
investment for an indefinite period and to afford a complete loss thereof. The
information set forth on the signature page hereto regarding the Subscriber is
accurate. The Subscriber was not formed for the specific purpose of acquiring
the Shares and is not a registered broker-dealer or an affiliate of a registered
broker-dealer.

(c)    Purchase for Investment. On the Effective Date, the Subscriber will
receive the Shares as principal for its own account for investment and not with
a view to any sale of other transfer thereof in contravention of the Securities
Act.

(d)    Compliance with the Securities Act. The Subscriber understands and agrees
that the Shares have not been registered under the Securities Act or any
applicable state securities laws by reason of their issuance in a transaction
that does not require registration under the Securities Act (based in part on
the accuracy of the representations and warranties of Subscriber contained
herein), and that such Shares must be held indefinitely unless a subsequent
disposition is registered under the Securities Act or any applicable state
securities laws or is exempt from such registration.
 
(e)    Restrictive Legend. The Shares will bear a customary restrictive
Securities Act legend in the form specified by the Company. The shares will
remain restricted for six months. After six months the company will exert good
faith efforts to have the restrictive legend removed.

(f)    Communication of Offer. The offer to sell the Shares was directly
communicated to the Subscriber by the Company. At no time was the Subscriber
presented with or solicited by any leaflet, newspaper or magazine article, radio
or television advertisement, or any other form of general advertising or
solicited or invited to attend a promotional meeting otherwise than in
connection and concurrently with such communicated offer.

(g)    Organization; Authority; Enforceability. Such Subscriber, if an entity,
is duly organized, validly existing and in good standing under the laws of the
jurisdiction of its organization (if such “good standing” concept is recognized
in such jurisdiction) with full right, corporate, partnership or trust power and
authority to enter into and to consummate the transactions contemplated by this
Agreement. This Agreement and other agreements delivered together with this
Agreement or in connection herewith have been duly authorized, executed and
delivered by the Subscriber and are valid and binding agreements enforceable in
accordance with their terms, subject to bankruptcy, insolvency, fraudulent
transfer, reorganization, moratorium and similar laws of general applicability
relating to or affecting creditors’ rights generally and to general principles
of equity; and Subscriber has full corporate, partnership, trust or similar
power and authority necessary to enter into this Agreement and such other
agreements and to perform its obligations hereunder and under all other
agreements entered into by the Subscriber relating hereto.

(h)    Correctness of Representations. The Subscriber represents as to such
Subscriber that the foregoing representations and warranties are true and
correct as of the date hereof and, unless a Subscriber otherwise notifies the
Company prior to the Closing, shall be true and correct as of the Closing Date.

(i)    Survival. The foregoing representations and warranties shall survive the
Closing Date for three years.

(j)    Restriction on Short Sales. The Subscriber agrees that, to the extent
required by law, it will not enter into or affect any short sale or other
hedging transaction with respect to the Company’s Common Stock.

(k)    Disclosure. The Subscriber acknowledges and agrees that the Company does
not make nor has made any representations or warranties with respect to the
Shares or the transactions contemplated hereby other than those specifically set
forth in Section 3 hereof.

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3.    Company Representations and Warranties. The Company represents and
warrants to and agrees with the Subscriber that on the date hereof:

(a)    Due Incorporation. The Company is a corporation duly organized, validly
existing and in good standing under the laws of the State of Delaware and has
the requisite corporate power to own its properties and to carry on its business
as now being conducted.

(b)    Outstanding Stock. All issued and outstanding shares of capital stock of
the Company has been duly authorized and validly issued and are fully paid and
non-assessable.

(c)    Authority; Enforceability. The Company has full corporate power and
authority necessary to enter into and deliver this Agreement and to perform its
obligations thereunder. This Agreement has been duly authorized, executed and
delivered by the Company and is a valid and binding agreement enforceable
against the Company in accordance with its terms, subject to bankruptcy,
insolvency, fraudulent transfer, reorganization, moratorium and similar laws of
general applicability relating to or affecting creditors’ rights generally and
to general principles of equity.

(d)    Consents. No consent, approval, authorization or order of any court or
governmental agency or body having jurisdiction over the Company is required for
the execution by the Company of this Agreement and compliance and performance by
the Company of its obligations hereunder, including, without limitation, the
issuance and sale of the Shares.

(e)    No Violation or Conflict. Assuming the representations and warranties of
the Subscribers in Section 3 are true and correct, neither the issuance and sale
of the Shares nor the performance of the Company’s obligations under this
Agreement and all other agreements entered into by the Company relating thereto
by the Company will:

(i)    violate, conflict with, result in a breach of, or constitute a default
(or an event which with the giving of notice or the lapse of time or both would
be reasonably likely to constitute a default) under (A) the certificate of
incorporation of the Company, (B) to the Company’s knowledge, any decree,
judgment, order, law, treaty, rule, regulation or determination applicable to
the Company of any court or governmental agency or body having jurisdiction over
the Company or over the properties or assets of the Company, (C) the terms of
any bond, debenture, note or any other evidence of indebtedness, or any
agreement, stock option or other similar plan, indenture, lease, mortgage, deed
of trust or other instrument to which the Company is a party, by which the
Company is bound, or to which any of the properties of the Company is subject,
or (D) the terms of any “lock-up” or similar provision of any underwriting or
similar agreement to which the Company is a party except the violation,
conflict, breach, or default of which would not have a material adverse effect
on the business, operations or financial condition of the Company and its
subsidiaries taken as a whole (a “Material Adverse Effect”);

(ii)    result in the activation of any anti-dilution rights or a reset or
repricing of any debt or security instrument of any other creditor or equity
holder of the Company, nor result in the acceleration of the due date of any
borrowing of the Company; or

(iii)    result in the activation of any piggy-back registration rights of any
person or entity holding securities of the Company or having the right to
receive securities of the Company.

(f)    The Shares. The Shares upon issuance in accordance with the terms of this
Agreement:

(i)    are, or will be, free and clear of any security interests, liens, claims
or other encumbrances, subject to restrictions upon transfer under the
Securities Act and any applicable state securities laws;

(ii)        will be duly and validly authorized, and on the date of issuance of
the Shares, the Shares will be duly and validly issued, fully paid and
non-assessable; and

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(iii)    will not have been issued or sold in violation of any preemptive or
other similar rights of the holders of any securities of the Company.
    
(g)    Litigation. There is no pending or, to the best knowledge of the Company,
threatened action, suit, proceeding or investigation before any court,
governmental agency or body, or arbitrator having jurisdiction over the Company
that would affect the execution by the Company or the performance by the Company
of its obligations under this Agreement, and all other agreements entered into
by the Company relating hereto. Except as disclosed in the Reports, there is no
pending or, to the best knowledge of the Company, basis for or threatened
action, suit, proceeding or investigation before any court or governmental
agency or body, which litigation if adversely determined could have a Material
Adverse Effect.

(h)    Reporting Company. The Company is a publicly-held company subject to
reporting obligations pursuant to the Securities Exchange Act of 1934, as
amended (the “Exchange Act”) and its shares of Common Stock are registered
pursuant to Section 12(b) of the Exchange Act. For the purposes of this
Agreement, the Company has timely filed all reports and other materials required
to be filed under the Exchange Act during the preceding twelve months.

(i)    Information Concerning the Company. The Reports contain all material
information relating to the Company and its operations and financial condition
as of their respective dates that was required by the Exchange Act to be
disclosed therein. Since the date of the financial statements included in the
Reports, there has been no Material Adverse Effect not disclosed in the Reports.
The Reports, at the time of filing, did not contain any untrue statement of a
material fact or omit to state a material fact required to be stated therein or
necessary to make the statements therein not misleading in light of the
circumstances when made.

(j)    No Integrated Offering. Neither the Company, nor any of its affiliates,
nor any person acting on its or their behalf, has directly or indirectly made
any offers or sales of any security or solicited any offers to buy any security
under circumstances that would cause the offer of the Shares pursuant to this
Agreement to be integrated with prior offerings by the Company so as to
invalidate any exemptions under the Securities Act for the offer and sale of the
Shares.

(k)    No General Solicitation. Neither the Company, nor any of its affiliates,
nor to its knowledge, any person acting on its or their behalf, has engaged in
any form of general solicitation or general advertising (within the meaning of
Reg. D under the Securities Act) in connection with the offer or sale of the
Shares.

(l)    No Material Undisclosed Events or Circumstances. Since the date of the
last Report filed under the Exchange Act, no event or circumstance has occurred
or exists with respect to the Company or its business, operations or financial
condition, that, under applicable law, rule or regulation, requires the filing
of a Report prior to the date hereof that has not been so filed.

(m)    Correctness of Representations. The Company represents that the foregoing
representations and warranties are true and correct as of the date hereof in all
material respects, and, unless the Company otherwise notifies the Subscribers
prior to the Closing, shall be true and correct in all material respects as of
the Closing Date.

(n)    Survival. The foregoing representations and warranties shall survive the
Closing Date for a period of three years.
  
4.    Reg. D Offering. The offer and issuance of the Shares to the Subscribers
is being made pursuant to the exemption from the registration provisions of the
Securities Act afforded by Section 4(a)(2) or Section 4(a)(6) of the Securities
Act and/or Rule 506 of Reg. D promulgated thereunder.

5.    Covenants of the Company. The Company covenants and agrees with the
Subscribers as follows:

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(a)    Exchange Act Filings. The Company shall file a Form 8-K with the SEC
disclosing the transactions contemplated by this Agreement within the time
period specified therefor by the rules and regulations under the Exchange Act.
The Company agrees to file a Form D with respect to the Shares as required under
Reg. D.

(b)    Reporting Requirements. Until all of the Shares have been resold or
transferred by all of the Subscribers, or, if earlier, two years after the
Closing Date, the Company will use commercially reasonable best efforts (i) not
to take any action or file any document (whether or not permitted by the
Securities Act or the Exchange Act or the rules thereunder) to terminate or
suspend the registration of the shares of the Company’s Common Stock under the
Exchange Act and (ii) to continue the listing of the shares of the Company’s
Common stock on the NYSE-MKT or other established trading market.

6.    Indemnification. The Parties will, to the extent permitted by law,
indemnify and hold harmless each other, each officer of the Parties, each
director of the Parties, and each other person, if any, who controls such
Parties within the meaning of the Securities Act, against any losses, claims,
damages or liabilities, joint or several, to which the Parties or such other
person (a “controlling person”) may become subject under the Securities Act or
otherwise, insofar as such losses, class, damages or liabilities (or actions in
respect thereof) (“Claims”) arise out of or are based upon any untrue statement
or alleged untrue statement of any material fact contained in the Agreement or
investor questionnaire at the time of its effectiveness, or arise out of or are
based upon the omission or alleged omission to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading in light of the circumstances when made, and will, subject to the
limitations herein, reimburse such party and each controlling person for any
legal or other expenses reasonably incurred by them in connection with
investigating or defending any such Claim, provided, however, that either Party
shall not be liable to each other to the extent that any Claim arises out of or
is based upon an untrue statement or alleged untrue statement or omission or
alleged omission made in conformity with information furnished by either Party
or any such controlling person in writing specifically for use in the Agreement
or investor questionnaire or related prospectus, as amended or supplemented.

7.    Miscellaneous.

(a)    Notices. All notices, demands, requests, consents, approvals, and other
communications required or permitted hereunder shall be in writing and, unless
otherwise specified herein, shall be (i) personally served, (ii) delivered by
reputable overnight courier service with charges prepaid, or (iii) transmitted
by fax, addressed, if to the Company, to Chief Financial Officer, American DG
Energy Inc., 45 First Avenue, Waltham, MA 02451, fax: (781) 622-1027, and if to
a Subscriber, to such Subscriber at the address set forth on the signature pages
hereto or to such other address as such party shall have specified most recently
by written notice.

(b)    Amendments; Waivers.
    No provision of this Agreement may be waived or amended except in a written
instrument signed, in the case of an amendment, by the Company and the
Subscribers. No waiver of any default with respect to any provision, condition
or requirement of this Agreement shall be deemed to be a continuing waiver in
the future or a waiver of any subsequent default or a waiver of any other
provision, condition or requirement hereof, nor shall any delay or omission of
either party to exercise any right hereunder in any manner impair the exercise
of any such right.

(c)    Legal Fees. Each party shall pay its own legal fees and expenses in
connection with the transactions contemplated by this Agreement.
 
(d)    Entire Agreement; Assignment. This Agreement and other documents
delivered in connection herewith represent the entire agreement between the
parties hereto with respect to the subject matter hereof. Neither the Company
nor the Subscribers have relied on any representations not contained or referred
to in this Agreement and the documents delivered herewith. No right or
obligation of either party shall be assigned by that party without prior notice
to and the written consent of the other party.

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(e)     Counterparts/Execution. This Agreement may be executed in any number of
counterparts and by the different signatories hereto on separate counterparts,
each of which, when so executed, shall be deemed an original, but all such
counterparts shall constitute but one and the same instrument. Signatures to
this Agreement may be delivered by fax or by scan/email.

(f)    Law Governing this Agreement. This Agreement shall be governed by and
construed in accordance with the laws of the Commonwealth of Massachusetts
without regard to principles of conflicts of laws. Any action brought by either
party against the other concerning the transactions contemplated by this
Agreement shall be brought only in the state courts of Massachusetts or in the
federal courts located in Massachusetts. The parties and the individuals
executing this Agreement and other agreements referred to herein or delivered in
connection herewith on behalf of the Company agree to submit to the jurisdiction
of such courts and waive trial by jury.

(g)    Independent Nature of Subscribers’ Obligations and Rights. The
obligations of the Subscriber hereunder are several and not joint with the
obligations of any other Subscriber hereunder, and no such Subscriber shall be
responsible in any way for the performance of the obligations of any other
hereunder.

(h)    Equitable Adjustment. The Shares and the Purchase Price Per Share shall
be equitably adjusted to offset the effect of stock splits, stock dividends, and
distributions of property or equity interests of the Company to its shareholders
prior to the Closing.

(i) Severability.     If any provision of this Agreement is held to be illegal,
invalid, or unenforceable under the present or future laws effective during the
term of this Agreement, such provision will be fully severable, and this
Agreement will be construed and enforced as if such illegal, invalid, or
unenforceable provision had never compromised a party of this Agreement, and the
remaining provisions of this Agreement will remain in full force and effect.

[Signature page immediately follows.]

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American DG Energy Inc.
Signature Page to Subscription Agreement

Please acknowledge your acceptance of the foregoing Subscription Agreement on
the date set forth above by signing and returning a copy to the undersigned
whereupon it shall become a binding agreement between us.

AMERICAN DG ENERGY INC.

_/s/ Gabriel J. Parmese______________

By: Gabriel J. Parmese
Chief Financial Officer and Treasurer
      

AGREED AND ACCEPTED:
SUBSCRIBER:

100,000 Peter Westerhoff
Common shares purchased              Subscriber's name

Subscriber's Signature

Peter Westerhoff, President, AES NJ Cogen Co, Inc
                            
Address of Subscriber
                                
Peter Westerhoff
4 Deer Trail
Kinnelon. NJ 07405

Email address: aesnjcohen@aol.com
                            
Fax number: 972-838-2567