AAON, Inc.

Conflict Minerals Report

For The Year Ended December 31, 2023

OVERVIEW

This report has been prepared by AAON, Inc. (herein referred to as “AAON,” the “Company,” “we,” “us,” or “our”) pursuant to Rule 13p-1 (the "Rule") promulgated under the Securities Exchange Act of 1934, as amended. Please refer to Rule 13p-1, Form SD and the 1934 Act Release No. 34-67716 for definitions to the terms used in this Report, unless otherwise defined herein. We are engaged in the engineering, manufacturing, marketing, and sale of premium air conditioning and heating equipment consisting of standard, semi-custom, and custom rooftop units, data centers cooling solutions, cleanroom systems, packaged outdoor mechanical rooms, air handling units, makeup air units, energy recovery units, condensing units, geothermal/water-source heat pumps, coils, and controls. We conducted an analysis of our products and found that small quantities of tin, tantalum, tungsten and gold ("3TG") are found in our products.

DUE DILIGENCE

Design of Due Diligence

Our due diligence measures have been designed to conform, in all material respects, with the due diligence framework presented by the The Organization for Economic Co-operation and Development ("OECD") in the publication OECD Due Diligence Guidance for Responsible Supply Chains of Minerals from Conflict-Affected and High-Risk Areas: Third Edition, OECD Publishing ("OECD Guidance") and the related Supplements for gold and for tin, tantalum and tungsten. The discussion below provides the applicable OECD Guidance recommendation followed by a summary of our activities in line with the OECD Guidance.

1. Establish strong company management systems.

•Adopt and clearly communicate to suppliers and the public, a company policy for the supply chain of minerals originating from conflict-affected and high risk areas. This policy should incorporate the standards against which due diligence is to be conducted.

We have adopted a conflict minerals policy related to our sourcing of 3TG, and communicated the policy to suppliers and the public through our website at aaon.com. The policy requires suppliers to perform due diligence and outlines our expectations of suppliers.

•Structure internal management to support supply chain due diligence.

We have established a management team to support supply chain due diligence related to 3TG. Our management team includes individuals from supplier management, engineering, accounting and legal.

•Establish a system of controls and transparency over the mineral supply chain.

As stated above, we have implemented a conflict minerals policy and have established our management team to support supply chain due diligence. Additionally, in 2014, we implemented the The Global e-Sustainability Initiative ("GeSI") and Electronic Industry Citizenship Coalition (“EICC”), known as the EICC-GeSI Conflict Minerals Reporting Template (the "Template"). The Template was developed to facilitate disclosure and communication of information regarding

smelters and refiners that provide material to a manufacturer’s supply chain. It includes questions regarding a direct supplier’s conflict-free policy, its due diligence process, and information about its supply chain such as the names and locations of smelters and refiners as well as the origin of 3TG used by those facilities. Utilizing the Template enhances our ability for information gathering and tracking, record maintenance, as well as information sharing regarding smelters and refiners.

•Strengthen company engagement with suppliers. A supply chain policy should be incorporated into contracts and/or agreements with suppliers.

The products that we manufacture typically contain hundreds of parts from many direct suppliers. We have relationships with a vast network of suppliers and there are generally multiple tiers between the 3TG mines and our direct suppliers. Therefore, we must rely on our direct suppliers to work with their upstream suppliers in order that they may provide us with accurate information about the origin of 3TG in the components we purchase.

•Establish a company-level, or industry-wide, grievance mechanism as an early warning risk awareness system.

We have established an email address to allow interested parties to contact us at conflictminerals@aaon.com with any questions or for more information.

2. Identify and assess risk in the supply chain.

Because of the complexity of our supply chain, we developed a risk-based approach that focused on our suppliers that we believed were likely to provide us with components and raw materials containing 3TG from the Covered Countries, as defined in the Rule. This was accomplished by the management team reviewing the listing of components and raw materials provided by all suppliers and identifying those components and raw materials that may contain 3TG. As stated above, we implemented the Template to facilitate our due diligence efforts for the current reporting period. We have determined that requesting our suppliers to complete the Template represents our reasonable best efforts to determine the mines or locations of origin of 3TG in our supply chain.

Responses were provided using the Template as well as other forms of communication utilized by the suppliers. We reviewed and evaluated the responses against criteria developed by our management team to determine which required further engagement. The criteria included inconsistent, incomplete and/or inaccurate responses, as well as responses that indicated the supplier potentially sources 3TG from Covered Countries under the Rule.

Our team identified 394 suppliers in the current reporting period based upon the criteria noted above. All of the suppliers were sent the Template (via mail) as well as a cover letter outlining the requirements of the Rule.

Of the 394 suppliers we sent the Template to, we received 99 responses, or a response rate of approximately 25 percent. The majority of responses received provided data at a company level. Of the 99 responses received, based upon review and evaluation against our criteria, we identified 19 suppliers whose response indicated that their company may have supplied components or raw materials containing 3TG that originated in or may have originated in the Covered Countries per the Rule. However, despite the due diligence we have undertaken during the reporting period, based upon the responses obtained, we are unable to determine whether the 3TG represented, that may have originated from the Covered Countries, were incorporated into the components or raw materials supplied to us in 2023. Therefore, we are unable to determine whether any of our products manufactured during the reporting period contained 3TG that originated from the Covered Countries.

3. Design and implement a strategy to respond to identified risks.

•Senior management is briefed about our due diligence efforts.

•We have adopted a conflict minerals policy and implemented a management team for oversight over the conflict minerals process.

•We have implemented a risk management plan that outlines the company responses to identified risks.

•We engage in regular ongoing risk assessment through our suppliers’ data submissions and focus on continuous improvement efforts to improve the return rate of our future survey efforts as well as the completeness and accuracy of our suppliers' responses.

4. Carry out independent third-party audit of supply chain due diligence at identified points in the supply chain.

We do not typically have a direct relationship with 3TG smelters and refiners and therefore do not perform or direct audits of these entities. We review public information provided by EICC and GeSI with respect to their Conflict-Free Smelter Program which is updated with such information.

5. Report on supply chain due diligence.

This Conflict Minerals Report constitutes our annual report on our 3TG due diligence, is available on our website at aaon.com and is filed with the Securities and Exchange Commission. As described in section 2, despite our due diligence efforts for the calendar year 2023, based upon the responses of our suppliers, we were unable to determine whether the 3TG represented to have originated from the Covered Countries were incorporated into the components or raw materials supplied to us during this reporting period.

Cautionary Note Concerning Forward-looking Statements

This report contains statements which, to the extent they are not statements of historical or present fact, are “forward-looking statements” as defined by the Private Securities Litigation Reform Act of 1995. Forward-looking statements include statements about AAON’s estimates, expectations, beliefs, intentions or strategies for the future, and the assumptions underlying these forward-looking statements, including, but not limited to, future financial performance, future opportunities and any other statements regarding events, opportunities or developments that AAON believes or reasonably anticipates will or may occur in the future. Words such as “expects”, “anticipates”, “intends”, “plans”, “believes”, “seeks”, “estimates”, “will”, “should”, “outlook”, “projected” and variations of such words and similar expressions are intended to identify these forward-looking statements. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date on which they are made. AAON undertakes no obligation to disseminate any updates or revisions to any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by federal securities laws. Forward-looking statements are not guarantees of future performance and involve certain risks, uncertainties and assumptions which are difficult to predict, including but not limited to economic, competitive, governmental and technological factors impacting AAON’s operations, supply chains, markets, products, services and prices. Therefore, actual outcomes and results may differ materially from what is expressed or forecasted in such forward-looking statements.

For a discussion of such risks and uncertainties, which could cause actual results to differ from those contained in the forward-looking statements, see “Risk Factors” and “Forward-Looking Statements” in AAON’s Annual Report on Form 10-K for the most recent fiscal year, as may be revised and updated by AAON’s Quarterly Reports on Form 10-Q, and AAON’s Current Reports on Form 8-K.