Comfort Systems USA, Inc. (FIX) | The Buildout — AI Infrastructure
The Verdict
Comfort Systems USA is a national mechanical and electrical contractor. It installs heating, ventilation and air-conditioning, plumbing, piping, controls, fire protection, and electrical systems in commercial, industrial, and institutional buildings, then maintains and services them. For the AI buildout, the relevant work is data centers: the company builds and prefabricates the mechanical and electrical plant that keeps compute running, sells directly to hyperscalers and to what management calls the most important intermediaries, and is expanding its modular, off-site construction capacity. Management describes its role as helping customers achieve delivered compute. It is not a chip, software, or model company; its exposure to AI is derivative, flowing from hyperscaler construction spending.
| Market Cap | — |
| Revenue (TTM) | $11.2B |
| Revenue Growth | +46.1% |
| EBITDA Margin (TTM) | 17.9% |
| Net Cash | $1.5B |
| Earnings Beats | 7 of 7 |
| P/E (TTM) | — |
| EV/EBITDA (TTM) | — |
What We Like
- Technology reached 58% of Q2 2026 revenue, up from 40% a year earlier — the data-center mix is taking a larger share of the whole business.
- Backlog was a record $14.1B at June 30, 2026, up $5.9B or 73% y/y, with $5.6B of that same-store and same-store backlog entering Q3 up 69%.
- Gross margin rose to 25.9% in Q2 2026 from 23.5%; excluding a $43M non-repeatable Q1 item, the underlying margin rose from 25.2% to 25.9% sequentially.
- Modular capacity is on a dated path — over 3.5M sq ft now, more than 4M by year-end 2026, about 5M by late summer 2027 — underwritten by multiyear volume commitments from two hyperscalers.
- The balance sheet carries net cash over $1.8B, $1.02B of available credit through October 2030, and positive free cash flow in each of the last 27 calendar years.
What We’re Watching
- Non-repeatable margin gains: Q1 2026 included $43M of favorable late-stage developments, and Q2's changes in estimates added about 7.7% to revenue, which management called close to double the prior-year impact.
- Heavy second-half 2026 comparables: management flagged some really, really heavy comparables coming up, especially in Q4, against a 47% six-month same-store pace.
- Customer and sector concentration: the top customer was 12.8% of 2025 revenue and is unnamed; Technology is 58% of revenue; two hyperscalers underwrite modular capacity.
- Power availability and siting: management called power a gating factor (get the power to do it) alongside data-center permitting scrutiny.
The thesis looks strengthening on the operating evidence: two guidance raises in two quarters, record backlog twice running, and a margin step-up the company has partly quarantined. The counterweights are also disclosed and specific — non-repeatable estimate gains, a Q4 comparable cliff, and a customer base that has become materially more concentrated in Technology. The open question is whether the mid-20s gross margin is a durable structural level or a favorable-revision artifact that has never been tested on the downside.
Earnings Beat
Q2 2026 revenue was $3.3 billion, the first quarter above $3 billion, up $1.1 billion year over year. Gross margin rose to 25.9% from 23.5% and operating margin reached 17.1%. Same-store revenue grew 44%. Free cash flow was $999 million, which management described as roughly 2.5x earnings, with about one-third possibly advanced customer cash.
| Metric | Q2 FY2026 | Q1 FY2026 | Q2 FY2025 | YoY |
|---|---|---|---|---|
| Revenue | $3.3B | $2.9B | $2.2B | +50.3% |
| Gross margin | 25.9% | 26.3% | 23.5% | +240bps |
| EBITDA | $598M | $524M | $334M | +78.8% |
| EPS | $12.51 | $10.49 | $6.52 | +91.9% |
| Backlog | $14.1B | $12.5B | $8.2B | +73% |
| Modular bookings | $510M | n/a | n/a | — |
We're not going to invest in buildings just on speculation. We expand when customers provide us meaningful multiyear commitments.— Trent McKenna, President, 2026-07-24
Management tone: Management escalated on both demand and caution in the Q2 2026 call. They raised the full-year same-store growth guide roughly 10 percentage points while flagging heavy fourth-quarter comparables. They disclosed an advanced cash component in the $999M free cash flow and offered a rough one-third split. And they volunteered that Q2's favorable estimate revisions were bigger than usual, repeating that Q1's $43M gain was not repeatable.
Management Guidance
For FY2026, management guides same-store revenue growth in the mid- to high 30% range, up from the mid- to high 20% range a quarter earlier. CapEx is guided at about 5% of revenue, the effective tax rate around 23%, and gross profit margins to continue in the strong ranges averaged in recent quarters. Modular capacity is targeted at more than 4 million sq ft in production by year-end 2026 and about 5 million sq ft by late summer 2027. Management says the guide is built bottom-up from field projections and has often erred conservative; it gave no numerical 2027 guidance.
Trajectory
Revenue has grown sequentially for five quarters, from $1,831M in Q1 FY2025 to $3,266M in Q2 FY2026, with the latest quarter up 14.0% sequentially. Gross margin expanded from 22.0% to 25.9% over that span and EBITDA margin from 13.3% to 18.3%. Management attributes the levels to project selectivity in a supply-constrained market, favorable pricing, and estimate revisions that have produced a net gain every year since at least 2005. The pressure point is arithmetic: six-month same-store growth of 47% must slow sharply to land the full-year mid-to-high-30s guide, and management flagged the fourth quarter as the hardest comparison.
The Model
The model projects FY+1 revenue of $12,950.0 million with EBITDA of $2,370 million, an 18.3% margin, and FY+2 revenue of $16,125 million with EBITDA of $2,999 million, an 18.6% margin. The near-term anchor is a record $14.1 billion backlog and a full-year 2026 same-store guide in the mid- to high 30% range. The FY+2 step-up leans on the modular capacity build reaching about 5 million sq ft by late summer 2027 and on the Technology mix holding near recent levels.
| Metric | FY2025 | Next FY (E) | Following FY (E) |
|---|---|---|---|
| Revenue | $9.1B | $12.9B | $16.1B |
| YoY Growth | — | +42.3% | +24.5% |
| EBITDA | $1.5B | $2.4B | $3.0B |
| EBITDA Margin | 16.1% | 18.3% | 18.6% |
Projections are the median of 4 independent model runs. The model’s revenue sits 9.3% above analyst consensus.
For FY2026, management guides same-store revenue growth in the mid- to high 30% range, up from the mid- to high 20% range a quarter earlier. CapEx is guided at about 5% of revenue, the effective tax rate around 23%, and gross profit margins to continue in the strong ranges averaged in recent quarters. Modular capacity is targeted at more than 4 million sq ft in production by year-end 2026 and about 5 million sq ft by late summer 2027. Management says the guide is built bottom-up from field projections and has often erred conservative; it gave no numerical 2027 guidance.
What Could Go Right — and Wrong
- Frontier-lab and colocation pilot contracts convert into programmatic revenue, which management says would require capacity beyond the 5M sq ft plan.
- A third hyperscaler relationship at the modular level broadens the customer base beyond the two underwriting current capacity.
- Gross margin holds in the mid-20s through the heavy Q4 2026 comparison, showing the step-up is structural rather than estimate-driven.
- Data-center service work converts from a long-term opportunity into a measurable revenue line as OEM warranties roll off.
- The estimate-revision tailwind holds at a normal level rather than reversing.
- The estimate-revision pattern reverses — it has never done so since at least 2005 and is untested on the downside.
- Hyperscaler data-center construction slows, delays, or reschedules.
- Power and permitting constraints delay projects in FIX's geographies rather than relocate them.
- The added modular capacity goes unfilled if new-customer programmatic revenue does not materialize.
- Advanced cash does not repeat, and free cash flow resets toward net income plus a little, as management itself expects.
Looking Ahead
Over the next twelve months the central question is whether demand and margins hold through the hardest comparisons. Management raised its full-year 2026 same-store guide to the mid-to-high 30% range but pre-warned that the next two quarters, especially the fourth, face heavy year-ago figures. Capacity is the other thread: modular square footage is scheduled to move from over 3.5 million now to more than 4 million by year-end 2026 and about 5 million by late summer 2027, gated on multiyear customer commitments. The company has given no numerical 2027 guidance, only continuing success into 2027.
- Q3 2026Q3 2026 results — Tests the raised mid-to-high-30s same-store guide.
- Q4 2026Q4 comparable cliff — Hardest year-ago comparison; management pre-flagged it.
- Year-end 2026Modular capacity 4M sq ft — More than 4 million sq ft in production targeted.
- Late summer 2027Modular capacity 5M sq ft — About 5 million sq ft of capacity targeted.
Financials
Annual Summary
| Metric | FY2024 | FY2025 | TTM | YoY |
|---|---|---|---|---|
| Revenue | $7.0B | $9.1B | $11.2B | +29.5% |
| Gross Margin | 20.9% | 23.9% | 25.7% | +302bps |
| EBITDA | $895M | $1.5B | $2.0B | +63.8% |
| EBITDA Margin | 12.7% | 16.1% | 17.9% | +337bps |
| Net Income | $522M | $1.0B | $1.4B | +95.7% |
| Free Cash Flow | $738M | $1.0B | $2.2B | — |
| Net Cash | — | — | — | — |
Key Ratios (Trailing)
- P/E TTM—
- EV/EBITDA TTM—
- EV/Revenue TTM—
- Price/FCF TTM—
- Gross Margin (TTM)25.7%
- EBITDA Margin (TTM)17.9%
- Net Margin (TTM)12.8%
- ROIC86.4%
- FCF Conversion107.4%
- SBC / Revenue0.3%
The Company
Comfort Systems USA is a national mechanical and electrical contractor. It installs, renovates, maintains, repairs, and replaces HVAC, plumbing, piping, controls, fire protection, and electrical systems, mostly for commercial, industrial, and institutional customers. The work is project-based: about 94.5% of revenue is installation, and about 5.5% is maintenance and repair service on installed systems. Customers span technology, manufacturing, healthcare, education, government, office, and retail. The Technology end-market, which management describes as dominated by data-center work, reached 58% of Q2 2026 revenue.
The company reports in two segments, Mechanical Services and Electrical Services, and runs 50 operating units across 190 locations in 142 cities in 27 states. It competes mostly on a local or regional basis. Projects average six to nine months and about $3.3 million; at March 31, 2026 the book held 8,048 projects worth $26.39 billion, with projects of $2 million or more accounting for about 94% of that value. Prices are typically fixed, and labor management and utilization have the most impact on project performance. Free cash flow has been positive in each of the last 27 calendar years.
Business Segments
Competitive Landscape
The base contracting business is competitive and local: the 10-Q describes a high degree of competition and low barriers to entry in most of the company's markets. Management frames the broader market as supply-constrained rather than demand-constrained, saying there is plenty more work it could take if it could possibly do it, and that it takes only work it knows it can perform. In modular, management says competitors are building, in most cases, the product FIX codesigned with its customers, and characterizes their entry as customers wanting more capacity rather than replacing FIX.
- EMCOR (EME)Named in FIX's 10-K among larger companies providing electrical and mechanical services.
- Everus (ECG)Names FIX as a competitor in its own filings; not discussed by FIX.
- Legence (LGN)Names FIX as a competitor in its own filings; not discussed by FIX.
Supply Chain
Comfort Systems buys chillers, cooling towers, switchgear, generators, and building-automation equipment from manufacturers it calls primary manufacturers, then installs and integrates them for data centers and other facilities. No supplier mentions FIX by name on its own calls; the read-through is triangulation.
More on FIX: Earnings recap