Good morning, ladies and gentlemen. It is now 8:00 A.M. Central Daylight Time, and time to begin our meeting. Please note that the polls are open and will remain open until we announce that the polls are closing. I'm Kevin Wheeler, Chairman, President, and Chief Executive Officer of A. O. Smith Corporation. I would like to welcome you to the A. O. Smith Annual Meeting of Stockholders. I will be serving as Chairman of this meeting. I'd like to start our meeting by introducing our Board of Directors, who are joining us virtually today: Ronald D. Brown, Dr. Ilham Kadri, Ajita G. Rajendra, Bruce M. Smith, Mark D. Smith, Idelle K. Wolf, and Gene C. Wulf, as well as our Directors-Elect also joining us virtually: Victoria M. Holt and Michael M. Larson, and also our retiring Directors: Paul W. Jones and William P. Greubel.
We have also invited our independent registered public accounting firm, Ernst & Young LLP, to join us for this meeting. Brian Kennedy is present virtually and representing Ernst & Young LLP. There are three items on the agenda requiring stockholder action at this meeting. There are no stockholder proposals for consideration. Jim Stern, Executive Vice President, General Counsel, and Secretary will serve as Secretary of this meeting. You may access a list of our stockholders during the meeting by using the dedicated link provided on this meeting website.
This meeting is held pursuant to the notice mailed on March 4th, 2021, to all stockholders of record as of February 16th, 2021, who are entitled to vote. We have affidavits of the mailing of the notice to stockholders. Upon review of the list of stockholders of the corporation and the proxies, there are present, virtually and by proxy, stockholders holding a majority of the total shares outstanding and entitled to vote. Notice of the meeting having been duly given and a quorum present, therefore the meeting is lawfully convened. Laura Jamison and Mark Petrarca have been appointed inspectors to record, count, and confirm the voting of this meeting.
Thank you, Jim. We will dispense with the reading of the minutes from last year's meeting. Minutes are on file in the office of the Corporate Secretary and are available upon request. Before proceeding with the three items on the agenda requiring stockholder action at this meeting, I would like to comment on our 2020 results and current operations. Before I begin my remarks, I would like to remind you that some of the comments that will be made during this virtual meeting will constitute forward-looking statements. These forward-looking statements are subject to risks that could cause actual results to be materially different. Those risks include, among others, matters that we have described on slide three. On slide four, A. O. Smith is a 146-year-old global manufacturer of innovative residential and commercial water heaters, boilers, and water treatment products.
Our sales totaled nearly $3 billion in 2020, and we employ approximately 14,000 people worldwide. Our products are manufactured in 22 factories around the globe. Before I begin discussing our 2020 recap on slide five, I want to send my deepest gratitude to the thousands of A. O. Smith employees who have been working under less-than-ideal conditions throughout the pandemic and who continue to keep our operations running, offices open, and customers in hot and treated water. Although a challenging year, our business has performed well in 2020 given the circumstances. North America Water Treatment grew 14% organically, driven by continued consumer demand for products promoting a safe home. The direct-to-consumer channel with our Aquasana brand, retail outlets with our A. O. Smith brand, and the dealer channel all contributed to solid 2020 growth. Industry shipments of U.S.
Residential water heaters, including tankless, surged to a record 10.1 million units, or 8% growth over the prior year. We believe the overall positive tone to new residential and safe-at-home remodel construction activity, including an increase in proactive replacement demand and channel inventory stocking related to extended industry lead times, resulted in above-trend growth in 2020. Due to construction project delays and postponements in North America, as well as a pandemic-related weakness in restaurant and hospitality new construction and replacement demand, we saw commercial water heater and boiler industry volumes decline by 8%-10%. We maintained our market share in both of these categories. We saw progressive year-over-year improvement in consumer demand for our products in China throughout 2020. As a result of higher volumes and diligent efforts by the team to reduce costs and reorganize, high single-digit margins were achieved in the second half of the year.
In North America, aside from the voluntary closure of our Mexican facility for several weeks in the second quarter, we remained operational throughout 2020 with no significant disruptions within our plants and our supply chain. Pandemic-related safety protocols remain in place in our facilities and offices. Due to strong residential water heater demand, coupled with self-quarantine-related absenteeism, our lead times remain above normal. To align our business with current global market conditions, we reduced headcount and incurred other restructuring costs totaling approximately $6 million after tax in 2020. The majority of these actions took place in China. We published our second corporate responsibility and sustainability report in early January. I am proud of our accomplishments since our first report, particularly in employee engagement, safety, resource reduction in our facilities, and a product portfolio that boasts some of the most efficient products in their respective categories.
We introduced our first-ever public greenhouse gas emission goal. We strive to reduce GHG emissions by 10% by 2025. Our 2020 financial performance is shown on slide six. Full-year sales of $2.9 billion declined 3% compared with 2019, largely due to significant weakness in our China business in the first half of 2020. As a result of lower sales, adjusted earnings declined 3% to $351 million, or $2.16 per share, compared with $370 million, or $2.22 per share in 2019. We believe that particularly in these volatile times, A. O. Smith is a compelling investment for a number of reasons. We have leading market share in our major product categories. We estimate replacement demand represents approximately 85% of North America water heater and boiler volumes.
We have a strong premium brand in China, a broad product offering in our key product categories, broad distribution, and a reputation for quality and innovation in that region. Over time, we are well-positioned to maximize favorable demographics in both China and India to enhance shareholder value. We have strong cash flow and an under-levered balance sheet, providing an opportunity to continue to invest in ourselves, our acquisitions, and return cash to shareholders. That concludes my comments. I also want to note that we did not receive any questions from stockholders and will now move to the business of the meeting. The first order of business is the election of directors. The proposed nominees for Class A Common Stock Directors are Victoria M. Holt, Michael M. Larson, Ajita G. Rajendra, Bruce M. Smith, Mark D. Smith, and Kevin J. Wheeler. The proposed nominees for Common Stock Directors are Ronald D.
Brown, Dr. Ilham Kadri, Idelle K. Wolf, Gene C. Wulf. If you haven't already voted, please do so now by following the instructions that are available on this virtual meeting website during this meeting. The second item is the advisory vote to approve the compensation for our named executive officers. If you haven't already voted, please do so now. The third item is the ratification of the selection of Ernst & Young LLP as the independent registered public accounting firm for the company for fiscal year 2021. Ernst & Young LLP has been appointed by the Board's Audit Committee, and the selection of Ernst & Young LLP has the approval of the entire board. Ernst & Young is in its 103rd consecutive year as A. O. Smith's auditor. If you haven't already voted, please do so now.
Now, if you have not had the opportunity to vote and are a stockholder of record, please vote at this time. The polls for voting will close in one minute. I would like to take this time to recognize and thank Paul Jones and Bill Greubel, who are retiring from the board today. Paul joined the board in 2004, and Mr. Grubel joined in 2006. Both men served on the Nominating and Governance and Personnel and Compensation Committees, with Bill chairing the Nominating and Governance Committee since 2011. On behalf of our entire A. O. Smith family, our employees, our Board of Directors, and stockholders, I would like to thank Paul and Bill for their excellent guidance, long service, and many contributions to our company.
I especially want to thank Paul for his vision and leadership as our Chairman and Chief Executive Officer during a transformative time as we move to a water technology company. We wish both of you nothing but the best in the future. With the polls closed and the vote summary report received from EQ Shareowner Services, Jim, will you please report out the results?
I have received the vote summary report from the inspectors of the election. It shows that based on preliminary tabulation of the votes cast, the nominees have been elected as directors, the compensation of named executive officers has been approved, and the appointment of Ernst & Young LLP as the company's independent registered public accounting firm for 2021 has been ratified. We will be reporting the final results in a Form 8-K to be filed within four business days.
Thank you, Jim. Based upon the results, I hereby declare that the nominees have been elected as directors. The compensation of named executive officers has been approved, and the appointment of Ernst & Young LLP as the company's independent registered public accounting firm for 2021 has been ratified. Seeing that there is no other business on the agenda, this meeting is adjourned. I would like to thank all stockholders who attended the meeting and all of those who submitted their proxies for the meeting. This concludes our annual stockholders' meeting. Thank you all for attending.