2 Hidden AI Infrustructure Stocks Up Over 100% in the Past Year

What do an HVAC company and a power-and-cooling equipment supplier have in common? Comfort Systems USA (NYSE: FIX) and Vertiv Holdings (NYSE: VRT) are both riding the artificial intelligence (AI) boom thanks to the data center build-out happening behind the scenes.

The market has noticed. Over the past year, Comfort Systems' stock has risen 214%, while Vertiv's has risen 131%. They're tied to AI infrastructure in very different ways, which matters when you're trying to figure out what's really driving the gains.

Two under-the-radar infrastructure plays have already more than doubled. The question now is whether the fundamentals still support the story. Let's find out.

Image source: Getty Images.

What Comfort Systems and Vertiv actually do for AI data centers

Comfort Systems is a specialized construction and building services company focused on the systems that make large facilities function. That includes mechanical, electrical, plumbing, HVAC, piping, controls, modular construction, monitoring, and fire-protection services.

Vertiv, on the other hand, sells critical digital infrastructure for data centers. Its products and services help data centers, communication networks, and industrial facilities stay powered, cooled, connected, and running reliably. That includes power-management equipment, thermal-management systems, racks, enclosures, monitoring software, and services that support the full life cycle of a data center.

Why the AI data center boom needs cooling, power, and building systems

Vertiv is the more obvious AI infrastructure pick at first glance. It supplies much of the equipment a data center needs to operate, especially around power and cooling. Comfort Systems takes a step back from the server floor, but it's still in the flow of the same trend.

Data centers generate enormous amounts of heat, and they need effective cooling and building systems to keep uptime high. As hyperscalers build and expand, they turn to companies that can design, install, and service those systems at scale. Comfort Systems has long been a leader in commercial HVAC, and it appears to be one of the biggest players in that market.

Q1 2026 results: The AI build-out is already showing up in earnings

The latest results from both companies suggest the AI data center build-out is showing up in financial performance, not just stock charts.

Comfort Systems reported first-quarter 2026 revenue of about $2.9 billion, up 57% year over year. Net income rose 119% to about $370 million. In its Q1 investor presentation, the company pointed to data centers and chip manufacturing as its strongest end markets, followed by life sciences and pharmaceuticals. It also reported a $12.4 billion backlog, up 81% from $6.9 billion last year.

Vertiv also posted strong growth. Q1 2026 revenue increased 30% to about $2.65 billion, and net income climbed 137% to around $390 million. CEO Giordano Albertazzi said the company's ability to meet evolving AI-related demands is driving the growth.

Taken together, these results suggest AI infrastructure spending is already translating into real business momentum for both companies.

Comfort Systems vs. Vertiv: Which AI infrastructure stock looks better now?

So which stock looks more compelling today? At the moment, Comfort Systems appears cheaper, trading at a price-to-earnings ratio of about 49 compared to Vertiv's multiple of about 73. Those are still high multiples, and it's fair to ask whether enthusiasm for AI infrastructure is pushing prices ahead of fundamentals.

The counterpoint is that this has been a common pattern across many AI-adjacent stocks. The bigger question is whether earnings can keep growing fast enough to catch up. If the AI infrastructure build-out stays strong for years, today's valuations may not look so extreme in hindsight.

Wall Street clearly likes both names. Each carries a "strong buy" consensus rating, and both sets of price targets imply roughly 45% to 50% upside over the next year. If I had to choose, Comfort Systems has the edge. It trades at a lower valuation while posting faster revenue and earnings growth than Vertiv, and that record backlog suggests data center-related demand could stay healthy for a while.

After all, when two "hidden" AI infrastructure stocks are already up triple digits in a year, the next move depends less on hype and more on whether the build-out keeps translating into backlog, revenue, and earnings.

Rick Orford has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Comfort Systems USA and Vertiv. The Motley Fool has a disclosure policy.