A. O. Smith (AOS) 10-K 2016 FY Annual report

Exhibit 23

Exhibit 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the Registration Statements (FormS-8 Nos.333-92329,333-92428,333-144950 and333-170436) pertaining to the A. O. Smith Corporation Long-Term Executive Incentive Compensation Plan, the A. O. Smith Combined Executive Incentive Compensation Plan and the A. O. Smith Combined Incentive Compensation Plan and in the related prospectuses of our reports dated February 17, 2017, with respect to the consolidated financial statements and schedule of A. O. Smith Corporation, and the effectiveness of internal control over financial reporting of A. O. Smith Corporation, included in this Annual Report (Form10-K) for the year ended December 31, 2016.

ERNST & YOUNG LLP

Milwaukee, Wisconsin

February 17, 2017

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