It's no secret that artificial intelligence (AI) data center spending is booming, but with investors increasingly worried about the rising costs of funding mammoth capital commitments, it's a good idea to look beyond the hyperscalers like Alphabet and focus on companies helping build data centers. One such company is Comfort Systems USA (FIX 2.49%). It's not a household name to most, but smart investors have enjoyed watching the stock rise an astonishing 495% over the last couple of years.
Comfort Systems USA and data centers
AI can do many wonderful things, but until the day comes when robots like Tesla's Optimus and its brethren can build, install, and maintain mechanical and electrical installations, there will be a need for Comfort Systems USA. The company specializes in mechanical services, with roughly three-quarters of revenue coming from mechanical services and the rest from electrical services. These services include heating, ventilation, and air conditioning (HVAC), plumbing, piping, and electrical systems.
Image source: Getty Images.
Why Comfort Systems' growth is exploding
While overall U.S. manufacturing construction spending is declining after the boom years (created by the CHIPS Act, infrastructure investment, supply chain rebuilding, and AI data center spending), it's still at a relatively high level.
US Manufacturing Construction Spending data by YCharts
Moreover, Comfort Systems' increasing focus on the still-booming AI data center growth is paying off. On the recent earnings call, management outlined that technology and industrial spending accounted for 67% of its volume in 2025, while "Data center work was 45% of our revenue, an increase from 33% the prior year."
The increasing relevance of AI data centers is evident in an astonishing chart of Comfort Systems' growing backlog.
Data source: Comfort Systems USA presentations. Chart by author.
It's better than you might think
It would be easy to point to the surging backlog and conclude that it reflects hyperscalers' current spending commitments for AI data centers, which could struggle to grow from current levels.
Indeed, a Wall Street analyst asked about the subject during the last earnings call, and management responded that the mechanical and electrical systems in a data center are actually late-cycle investments. CFO William George noted: "We are not booking backlog for things that are being committed to today. We are really working on things that came up at, you know, one to two and a half years ago."
In other words, the massive spending commitments made by Alphabet, Amazon, and other hyperscalers in 2026 are not yet fully reflected in Comfort Systems' backlog.
NYSE: FIX
Key Data Points
A stock to buy?
Revenue, earnings, and cash flow are set to balloon in the coming years. The Wall Street consensus calls for earnings per share to increase by 69% from $28.88 in 2025 to $48.92 in 2028, putting it on 30 times estimated 2028 earnings based on the current price. That looks too rich for me, but the stock will suit investors bullish on the AI data center spending theme over the next decade.
