Mike Wagnes
Senior Vice President, Chief Financial Officer at Allegion
Thanks, John, and good morning, everyone. Thank you for joining today's call. Please go to Slide number 5. As John shared, our Q4 results solid performance from the Allegion team, delivering another quarter of margin expansion with mid-single-digit top line growth. Revenue for the fourth quarter was $945.6 million, an increase of 5.4% compared to 2023. Organic revenue increased 3.5% in the quarter as a result of favorable price and volume.
We saw strength within our Americas segment, with International organic revenue down slightly in the quarter. Q4 adjusted operating margin increased by 10 basis points, driven primarily by volume leverage and favorable mix. Price and productivity, net of inflation and investment, was a slight headwind in Q4, but strong for the full year. I am pleased with the 70 basis points of operating margin expansion for the full year 2024.
Adjusted earnings per share of $1.86 increased $0.18 or 10.7% versus the prior year. Operational performance, favorable tax and accretive capital deployment more than offset a slight headwind from interest and other. Finally, full year 2024 available cash flow was $582.9 million, which was a 12.9% increase versus last year. We continue to effectively manage working capital and generate strong cash flow. I'll provide more details on our balance sheet and cash flow a little later in the presentation. Please go to Slide number 6.
This slide provides an overview of our quarterly revenue. I will review our enterprise results here before turning to our respective regions. Organic revenue grew 3.5% in the quarter, which included volume growth of 2.9% and price realization of 0.6%. Price realization stepped down about 1 point in the fourth quarter versus Q3, largely due to timing of rebate accruals in the Americas business compared to prior year.
For the full year, the enterprise had solid price realization of 2.4%. And as we think about 2025, we expect continued price realization. Acquisitions drove 2 points of growth in the quarter and currency was a slight headwind, bringing total reported growth to 5.4%. Please go to Slide number 7.
Our Americas segment delivered strong operating results in Q4. Revenue of $750 million was up 6.4% on a reported basis and up 4.6% on an organic basis. Organic growth included both favorable price and volume in the quarter. Reported revenue includes 1.9% growth from acquisitions and a slight currency headwind.
Our residential business was up high single digits in the quarter. The quarter was stronger than expected as some of our residential customers pulled in purchases ahead of inflation and tariff uncertainty. We believe underlying residential markets likely grew more in line with the previous couple of quarters. As a result, Q4 revenue was benefited by approximately mid-single-digit millions of dollars.
Our nonresidential business increased mid-single digits organically in the quarter as institutional end markets remained stable. We did not have pull-ahead within our nonresidential customers. Electronics revenue was up low single digits compared to Q4 last year. As we discussed on prior calls, electronic comparisons in recent years have reflected the timing of supply chain disruptions in prior years.
Americas adjusted operating income of $205.1 million increased 8.9% versus the prior year period. Adjusted operating margin was up 70 basis points as a result of favorable volume leverage and accretive acquisitions. Price and productivity, net of inflation and investments, was a slight headwind in Q4, but strong for the full year. Please go to Slide number 8.
Our International segment had a tough fourth quarter driven by a challenging macroeconomic environment, particularly in Germany, which is our largest market internationally. Revenue of $195.6 million was up 1.5% on a reported basis and down 0.7% organically. Acquisitions were a tailwind this quarter, positively impacted reported revenue by 2.4%. Currency was a slight headwind in the quarter versus prior year.
China was also a headwind to International organic growth. We took additional steps in the quarter to exit our already small operations there. In total, we had approximately $5 million of revenue in full year 2024, which represents a slight headwind to 2025 organic growth.
International adjusted operating income of $30.9 million decreased 4.3% versus the prior year period. Adjusted operating margin for the quarter decreased 100 basis points. While price and productivity exceeded inflation and investments, margin declines were due to lower volumes.
Please go to Slide 9, and I will provide an overview of our cash flow and balance sheet. 2024 available cash flow came in at approximately $583 million, up $66.5 million versus the prior year. This increase is driven by higher earnings and improvements in working capital, partially offset by higher capital expenditures.
Working capital as a percent of revenue improved as we continue to focus on working capital efficiency to convert earnings to cash. We saw improvements in both inventory turns and DSO this year, which drove the improvement.
Finally, our balance sheet remains strong. Our net debt to adjusted EBITDA is at a healthy ratio of 1.6 times. Our business continues to generate strong cash flow and our balance sheet supports continued capital deployment.
I will now hand the call back over to John.