Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

CECO Environmental Corp. and Subsidiaries

Dallas, Texas

We hereby consent to the incorporation by reference in the Prospectus constituting a part of this Registration Statement of our reports dated March 14, 2022, relating to the consolidated financial statements and the effectiveness of CECO Environmental Corp. and Subsidiaries’ internal control over financial reporting appearing in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021.

We also consent to the reference to us under the caption “Experts” in the Prospectus.

/s/ BDO USA, LLP

Cincinnati, Ohio

May 2, 2022