Hannon Armstrong Sustainable Infrastructure Capital, Inc.

$135,000,000

4.125% Convertible Senior Notes due 2022

This pricing term sheet supplements Hannon Armstrong Sustainable Infrastructure Capital, Inc.’s preliminary prospectus supplement, dated August 15, 2017 (the “Preliminary Prospectus Supplement”), including the documents incorporated by reference therein, relating to the offering of the Notes, and supersedes the information in the Preliminary Prospectus Supplement to the extent inconsistent with the information in the Preliminary Prospectus Supplement. In all other respects, this pricing term sheet is qualified in its entirety by reference to the Preliminary Prospectus Supplement. Terms used herein but not defined herein shall have the respective meanings as set forth in the Preliminary Prospectus Supplement. All references to dollar amounts are references to U.S. dollars. Unless the context otherwise requires, references to “Hannon Armstrong” or the “Issuer,” “we,” “us” and “our” in this pricing term sheet mean Hannon Armstrong Sustainable Infrastructure Capital, Inc. and not its subsidiaries.

The exact stock prices and effective dates may not be set forth in the table above, in which case:

Notwithstanding the foregoing, in no event will the conversion rate be increased on account of a make-whole fundamental change to exceed 44.0528 shares of our common stock per $1,000 principal amount of Notes, subject to adjustment in the same manner as the conversion rate is required to be adjusted as set forth under “Description of the Notes—Conversion Rights—Conversion Rate Adjustments” in the Preliminary Prospectus Supplement.

*An explanation of the significance of a rating may be obtained from the rating agency. Generally, rating agencies base their ratings on such materials and information, and such of their own investigations, studies and assumptions, as they deem appropriate. The rating of the Notes should be evaluated independently from similar ratings of other securities. A credit rating of a security is not a recommendation to buy, sell or hold securities and may be subject to review, revision, suspension, reduction or withdrawal at any time by the assigning rating agency.

General

This communication is intended for the sole use of the person to whom it is provided by the sender.

This communication shall not constitute an offer to sell or the solicitation of an offer to buy securities nor shall there be any sale of these securities in any state or jurisdiction in which such solicitation or sale would be unlawful prior to registration or qualification of these securities under the laws of any such state or jurisdiction.

This pricing term sheet does not contain a complete description of the Notes or the Notes offering. It should be read together with the Preliminary Prospectus Supplement and the accompanying Prospectus.

The Issuer has filed a registration statement (including a Prospectus, dated August 4, 2017, and a Preliminary Prospectus Supplement, dated August 15, 2017) with the Securities and Exchange Commission, or SEC, for the offering of the Notes. Before you invest, you should read the Preliminary Prospectus Supplement, the accompanying Prospectus and the other documents the Issuer has filed with the SEC for more complete information about the Issuer and the offering of the Notes. You may get these documents for free by visiting EDGAR on the SEC’s website at www.sec.gov. Alternatively, copies may be obtained from Deutsche Bank Securities Inc. at 60 Wall Street, New York, NY 10005-2836, Attention: Prospectus Group, Telephone: (800) 503-4611, Email: prospectus.cpdg@db.com, Merrill Lynch, Pierce, Fenner & Smith Incorporated, toll-free: 1-800-294-1322, or J.P. Morgan Securities LLC c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717, toll-free: (866) 803-9204, email: prospectus-eq_fi@jpmchase.com.

ANY DISCLAIMERS OR OTHER NOTICES THAT MAY APPEAR BELOW ARE NOT APPLICABLE TO THIS COMMUNICATION AND SHOULD BE DISREGARDED. SUCH DISCLAIMERS OR OTHER NOTICES WERE AUTOMATICALLY GENERATED AS A RESULT OF THIS COMMUNICATION BEING SENT VIA BLOOMBERG OR ANOTHER EMAIL SYSTEM.