EXHIBIT 23.1 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the incorporation by reference in the registration statements on Form S-8 (numbers 333-104700 and 333-14743) of Napco Security Systems, Inc. of our report dated September 14, 2004, appearing in this annual report on Form 10-K of Napco Security Systems, Inc. for the year ended June 30, 2004. Woodbury, New York September 23, 2004 24 E-122