CECO vs DCI: Which Is the Better Buy in 2026?

Same yardstick, side by side (as of September 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.

Reading it: DCI is the cheaper of the two on forward earnings, but cheaper is not the same as better. Pair the valuation with growth (how far the forward P/E sits below the trailing P/E) and risk (beta) before you decide.

The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. CECO and DCI share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.

This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined CECO and DCI exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.

CECO Environmental was incorporated in 1966 and now runs out of Addison, Texas, just outside Dallas. It sells engineered equipment that cleans, moves, separates, quiets and heats industrial process streams: selective catalytic reduction systems and gas turbine inlet and exhaust packages for power plants, cyclones and dust collectors for cement and metals, thermal oxidizers and scrubbers for chemicals, filtration and fluid handling for semiconductors and food processing, and acoustic enclosures where noise limits are part of the permit. The business is reported in two segments, Engineered Systems and Industrial Process Solutions. On June 1, 2026 CECO closed a roughly $2.2 billion combination with Thermon Group, a maker of electric and steam heat tracing, controllers, boilers and thermal fluid heaters, adding a business with roughly $520 million of annual revenue, gross margins near 45 percent and a large recurring maintenance component. CECO shareholders own about 62.5 percent of the combined company.

Full CECO guide

Donaldson Company, Inc. (NYSE: DCI) makes filtration systems and, more importantly, the replacement filters that go into them. Three segments carry the business: Mobile Solutions, the largest at roughly ~62% of fiscal 2025 sales, covering air and liquid filters plus emissions systems for off-road machinery, trucks and the independent aftermarket; Industrial Solutions, covering dust collection, compressed air, gas turbine intake and, since May 2026, jet fuel filtration through the acquired Facet business; and Life Sciences, a smaller unit spanning food and beverage process filtration, disk-drive filters and an assembled bioprocessing portfolio built from Solaris, Purilogics, Isolere Bio and Univercells Technologies. Filters are consumable and often regulated, so a machine sold once generates parts revenue for a decade or more.

Full DCI guide

Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.

• CECO drivers: Natural gas power and the data center buildout; Thermon and the shift toward recurring revenue.
• DCI drivers: Replacement filters as the recurring base; Facet and a heavier aerospace, defense and power tilt.

A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: Project revenue is lumpy, and a book to bill above two in one quarter does not repeat forever. For DCI, mobile Solutions ties a majority of revenue to off-road and on-road equipment cycles, so agriculture, construction and truck build rates set the direction of first-fit volumes regardless of how steady the aftermarket is.

Pick CECO if you believe its drivers more; DCI if you believe its. Many investors hold both, but since they share themes, that is a concentrated bet, not diversification. Decide deliberately and check overlap. For the full detail, see the CECO and DCI guides.

CECO. The trailing numbers and the forward numbers describe two different companies, because Thermon only joined on June 1, 2026 and the 2026 guide carries seven months of it. That gap is why the GAAP multiple looks extreme while the forward multiple looks like an ordinary growth industrial. Anyone reading CECO on trailing figures alone will misprice it in one direction, and anyone reading it purely on guidance assumes the synergy and conversion plan lands.

DCI. Fiscal 2026 ends July 31, so the April quarter is the most recent reported period and fourth-quarter results are due August 26, 2026. GAAP EPS of ~$1.00 versus ~$0.48 a year earlier overstates the underlying improvement, because the prior-year quarter absorbed a ~$62.0 million impairment; adjusted EPS rose a more ordinary ~7.1% to ~$1.06. Nine-month operating cash flow of ~$293.8 million funded ~$104.0 million of dividends and ~$108.5 million of buybacks before repurchases were paused, with the quarterly dividend at ~$0.32 per share for a yield near ~1.3%.

Headline figures (approximate, August 2026): CECO shows revenue (ttm) ~$804M, with FY2025 revenue of ~$774M, up ~39%, fy2026 guidance (with thermon) Revenue ~$1.275B to ~$1.375B, adjusted EBITDA ~$195M to ~$225M, q1 2026 orders and backlog Orders ~$450M (up ~97%), backlog ~$1.035B, book to bill ~2.2x, q1 2026 margins Gross margin ~31%, adjusted EBITDA margin ~9.9%, adjusted EPS ~$0.36; DCI shows revenue (ttm) ~$3.81B (+4.4% YoY), q3 fy2026 sales (quarter ended apr 30, 2026) ~$995M (+5.8% YoY), a record, adjusted operating margin ~16.6% in Q3 FY2026, an all-time high, fy2026 adjusted eps guidance ~$3.94 to ~$4.01 (7% to 9% growth).

CECO and DCI are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined CECO and DCI exposure against your real portfolio. It is not an investment adviser.