Partners Group-backed PremiStar acquires Salt Lake City's MSS, enters Utah and Kelso Industries' home market

On June 10, 2026, Deerfield, Illinois-based PremiStar announced that Mechanical Service & Systems (“MSS”) of Salt Lake City has joined the PremiStar family of companies. The transaction extends PremiStar's commercial HVAC, plumbing, and building automation footprint into Utah for the first time and adds capabilities serving manufacturing, mission-critical, healthcare, life sciences, education, aerospace, and commercial real estate end markets. Terms of the transaction were not disclosed.

Founded in 1984, MSS is one of the few full-service commercial mechanical contractors operating in Utah, offering design-build, installation, repair, and preventive maintenance for HVAC, plumbing, boilers, controls, and fabrication under one roof. The company received Rio Tinto's “Contractor of the Year — Worldwide” award in 2022. President Rick Cowley and his leadership team will continue running the business, with MSS joining PremiStar's network of regional owner-operators.

About PremiStar

PremiStar, formerly Reedy Industries, operates 62 branches across 19 states and employs more than 3,100 people. The company was founded in 1930 by Thomas “TJ” Reedy and is led today by CEO Joe Kirmser. Audax Private Equity recapitalized Reedy in 2019 and completed 15 add-on acquisitions during its hold. In August 2021, Partners Group — the global private markets firm with extensive experience scaling commercial and facility services businesses — acquired the company from Audax, with the Reedy family, management, and Audax all retaining minority stakes. The rebrand to PremiStar followed.

Recent PremiStar add-on activity

The MSS transaction continues an active pace of regional add-ons under Partners Group ownership. A non-exhaustive look at PremiStar's recent M&A activity:

April 2026 — Armistead Mechanical (New Jersey and the Hudson Valley region of New York).

February 2026 — McCormick Allum (Springfield, Massachusetts — partnered with Air Temp Mechanical, a PremiStar company).

October 2025 — Smith's Refrigeration (Lumberton, North Carolina — expanding into the Carolinas).

July 2025 — Rabe Environmental Systems (Erie, Pennsylvania — a 1916-founded mechanical contractor).

July 2025 — Farmer & Irwin (Southeast Florida).

June 2025 — B.T. Lindsay & Co. (West Hartford, Connecticut — under Air Temp Mechanical).

March 2025 — Dahme Mechanical HVAC services division (Countryside, Illinois).

January 2025 — Air Temp Mechanical (Connecticut's largest independent commercial HVAC contractor — CT entry).

January 2025 — Trademark Mechanical (Elmsford, New York — NYC metro entry).

December 2024 — Chadwick Service Company (Philadelphia metro).

November 2024 — Conditioned Air Design (Wisconsin).

That cadence — eleven publicly disclosed add-ons in roughly 18 months ahead of the MSS deal — reflects a platform with full-time M&A infrastructure. Bill Tamul joined as VP of M&A in March 2024, and the company runs a formal Acquisitions Program as a stated growth lever.

The Kelso Industries dynamic in Utah

What makes the Utah entry notable beyond geographic expansion is the competitive backdrop. Salt Lake City is effectively the home base of Kelso Industries, a separate PE-backed commercial MEP roll-up that has grown from zero to more than $1.2 billion in annual revenue in approximately five years through 31+ acquisitions. Kelso was founded by Steve Carroll in 2020, is headquartered in Phoenix but operates actively across Arizona, Utah, and Idaho, and is sponsored by Oxbow Equity Partners and Peterson Partners — both Salt Lake City-based investment firms — alongside a $50 million preferred equity investment from Dallas-based Paceline Equity Partners in 2023.

Kelso's growth model leans heavily on a partnership structure where sellers retain 20-40% equity and continue operating their businesses post-close. The platform targets the same broad mechanical, electrical, and plumbing services landscape as PremiStar, though Kelso has been more explicit about building toward a full MEP+ offering through partnerships with electricians and plumbers, while PremiStar has historically led with HVAC, plumbing, and building automation.

With the MSS transaction, PremiStar is now competing for the same Utah end customers — manufacturing, mission-critical, healthcare, life sciences, and commercial real estate clients — that Kelso has been actively building share with from its Phoenix-Utah-Idaho corridor. It is the first material overlap between the two platforms in a single MSA and is worth watching as a proxy for how the commercial MEP roll-up market plays out at the regional level when multiple well-capitalized platforms converge.

What this means for the MEP landscape

The PremiStar-MSS transaction reinforces a dynamic now visible across most major U.S. metros: multiple well-funded commercial HVAC, plumbing, and electrical platforms are actively competing for the same regional acquisition targets, and the buyer universe for established commercial MEP businesses has never been deeper. For independent owners, this means real choice — not just on valuation, but on deal structure (full sale vs. partial rollover), post-close operating role, the kind of sponsor sitting behind the platform (sponsor-to-sponsor track record matters), and what the platform actually wants to do with the business after closing. Those choices look very different from one acquirer to the next, and the difference compounds materially over a five-to-ten year horizon.