Flex Air
Flex Air, a division of Miller Industries, designs and manufactures custom modular HVAC, mechanical, and electrical systems — including AHUs, substations, and modular data centers — for enterprise customers across automotive, pharmaceutical, data center, healthcare, higher education, and aerospace sectors in North America.
- Company typePrivate
- Founded2015
- HeadquartersFenton, United States
- Headcount51–100
- GTM typeB2B
- OfferingHardware or Manufacturing
What Flex Air does
Flex Air, founded in 2015 as a division of Miller Industries, LLC, designs, engineers, and manufactures custom modular HVAC, mechanical, and electrical systems for industrial and commercial customers across North America. Operating from its Fenton, Michigan headquarters and manufacturing facility, the company produces custom air handling units (large-scale and penthouse configurations), modular electrical substations up to 10,000 KVA / 5.6 MW, pre-fabricated mechanical plants (boiler and chiller plants), modular data center modules (rack-level pods, containerized, cabin-style, and subsystem), and modular room solutions (cleanrooms, control rooms, team rooms). All systems are fabricated in a controlled factory environment with in-house PE-stamped engineering, then shipped to customer sites for rapid installation.
The company's customer base is concentrated in enterprise accounts spanning automotive OEMs (Ford, GM, Stellantis), industrial automation (Siemens, Schneider Electric, Cummins), aerospace (GE Aerospace), data centers (Sabey), pharmaceutical and healthcare (Allegheny Health, WVU Ruby Memorial), higher education (University of Michigan, University of Delaware), and defense (Leidos). Sales are executed through a direct enterprise field-sales motion with collaborative design engineering, custom solution development, and installation support. Revenue is project-based from one-time system sales, supplemented by recurring preventative maintenance and professional engineering services.
Flex Air is privately held by the Miller family under a Co-CEO structure (Matt Miller and Chad Miller), with no external institutional capital. In 2025, parent Miller Industries broke ground on a $43 million, 244,000 sq ft manufacturing expansion in Fenton to serve growing demand from semiconductors and electrical substations, supported by a $1 million Michigan Business Development Program grant and a PA 198 tax abatement. The company has also launched a USDOL-approved apprenticeship program with Mott Community College to build a skilled trades pipeline of electricians and welder-fitters.
Flex Air firmographics
Firmographics- Name
- Flex Air
- Legal name
- Flex Air (a division of Miller Industries, LLC)
- Website
- https://flexairmi.com
- Company type
- Private
- Founded year
- 2015
- Operating status
- Operating
- Headcount range
- 51–100 employees
- Short description
- Flex Air, a division of Miller Industries, designs and manufactures custom modular HVAC, mechanical, and electrical systems — including AHUs, substations, and modular data centers — for enterprise customers across automotive, pharmaceutical, data center, healthcare, higher education, and aerospace sectors in North America.
- Ownership category
- akta.pro rank
Flex Air industry classification
Industry- Product category
- Industrial Modular HVAC and Mechanical Systems
- NAICS
- Air-Conditioning and Warm Air Heating Equipment and Commercial and Industrial Refrigeration Equipment Manufacturing (333415)
- SIC
- Air-Cond & Warm Air Heatg Equip & Comm & Indl Refrig Equip (3585)
- akta.pro primary industry
- Air Handling Units (AHUs) & Rooftop Units (RTUs) (IMADANAA)
- akta.pro secondary industry
- HVAC Equipment (Heating, Cooling & Air Handling) (IMAHAKAB)
Keywords
Where Flex Air is headquartered
LocationHeadquarters
- HQ city
- Fenton
- HQ country
- United States
- HQ region
- North America
Offices1 record
Markets served
Flex Air business model
Business model- GTM type
- B2B
- Offering type
- Hardware or Manufacturing
- Cost components
- Personnel, Supply Chain, Operations, Technology or R&D, Infrastructure, Marketing or Sales
Revenue model
- Custom Modular System Sales: Project-based revenue from design, engineering, manufacturing, and delivery of custom modular HVAC, mechanical, and electrical systems. Customers include automotive OEMs, pharmaceutical companies, data centers, and industrial facilities. Projects range from individual air handling units to complete central utility plants.
- Engineering and Installation Support Services: Professional engineering services for custom system design and installation support. Work closely with customer facility managers and staff to coordinate seamless installation and commissioning.
- Preventative Maintenance and Restorative Services: Ongoing maintenance contracts and restorative/retrofit services for existing modular and conventional HVAC/mechanical systems.
Go-to-market motion1 record
Distribution channels1 record
Marketing channels5 records
Flex Air product offering
Product offeringCore offering
Flex Air designs, engineers, and manufactures custom modular air handling units (AHUs), modular mechanical systems (boiler plants, chiller plants, HVAC skids), and modular electrical substations in a controlled factory environment, then ships them to customer sites for rapid installation. The company sells directly to enterprise customers including automotive OEMs, pharmaceutical manufacturers, data center operators, healthcare systems, and universities across North America.
Product overview
Flex Air, a division of Miller Industries (established 2015), provides custom modular and air handling systems for industrial and commercial applications across North America, Canada, and Mexico. Their portfolio centers on custom modular solutions including Custom Large Air Handling Units and Custom Penthouse Air Handling Units (AHUs), paired with Modular Electrical Systems (substations, switch gear) and Modular Mechanical Systems (chiller plants, boiler plants, HVAC skids). Additional offerings include Modular Data Centers (rack-level pods, containerized modules, cabin-style modules, subsystem modules) and Modular Room Solutions (team rooms, control rooms, cleanrooms). These prefabricated products are designed for rapid deployment, improved speed-to-market, reduced labor costs, and minimal on-site space requirements, serving diverse industries including automotive, pharmaceutical, healthcare, data centers, food & beverage, higher education, and aerospace.
Differentiator
Problem solved
Functional benefit
Products and services
- Custom Large Air Handling Units (AHUs)
Quantifiable outcome
- Reduced installation time by 30-50% compared to traditional construction
- +4 more outcomes
Companies that use Flex Air
Customer profileNamed customers15 records
Segments7 records
Ideal customer profiles4 records
Flex Air technology and API
TechnologyTechnology focussed No
API detail
- Has API
- No
- API docs
- API detail
Core technology
AI maturity
App detail
Feature5 records
Flex Air partnerships and signals
Strategic signalPartnerships
One partnership is on record.
- Mott Community CollegeminorMiller Industries (parent company of Flex Air) partnered with Mott Community College for USDOL-approved apprenticeship programs. Electrician Apprenticeship Program includes 615 hours classroom training at Mott Community College plus 8,000 hours on-the-job training. Welder-Fitter Apprenticeship Program includes 600 classroom training hours at Mott Community College plus 8,000 hours on-the-job training. Programs span four years and support workforce development in the local Michigan community.
Scale indicators8 records
Recent moves8 records
Expansion highlights5 records
Flex Air competitors and assessment
Company assessmentBroad incumbents
- Carrier Global: Major HVAC OEM producing commercial and industrial air conditioning, heating, and refrigeration systems. Carrier's modular and custom-engineered solutions directly overlap with Flex Air's industrial AHU and modular mechanical system portfolio.
- Trane Technologies: Global HVAC and building systems OEM (Thermo King, Trane) with extensive commercial/industrial air handling unit and modular offerings. Directly comparable to Flex Air's custom AHU and modular HVAC product lines, though at much larger scale and broader portfolio.
- Eaton: Power management company producing modular substations, switchgear, and electrical infrastructure for industrial, data center, and utility customers. Comparable to Flex Air's modular electrical substation capabilities and similar data center customer base.
- Daikin Applied: Subsidiary of Daikin Industries producing commercial and industrial HVAC equipment including chillers, AHUs, and modular systems. Directly competes with Flex Air's commercial AHU and modular mechanical plant offerings.
- Johnson Controls (York): Building technologies and HVAC manufacturer (York, Hitachi) producing chillers, AHUs, and modular mechanical systems for commercial and industrial facilities. Competes with Flex Air across multiple verticals including healthcare, data centers, and higher education.
- ABB (Electrification): Global electrification and automation company producing modular electrical substations, switchgear, and power distribution products. Directly competes with Flex Air's Modular Electrical Substations product line for industrial and utility customers.
Direct peers
- Vertiv Holdings: Pure-play provider of critical digital infrastructure including modular data centers, precision cooling, and power management. Closely comparable to Flex Air's Modular Data Center product line and a direct competitor for Sabey-class and hyperscale modular infrastructure projects.
- Modine Manufacturing: Manufacturer of thermal management technology for HVAC, refrigeration, and industrial applications, including custom-engineered heat transfer and air handling products. Similar mid-sized custom industrial thermal equipment manufacturer profile to Flex Air.
- Kelvion: Manufacturer of heat exchangers and custom industrial cooling/air handling solutions for HVAC, power, data center, and industrial applications. Closely comparable mid-sized custom thermal equipment manufacturer serving overlapping industrial customer base.
- Stellar (Stellar Industries): Designer and manufacturer of custom modular mechanical systems, modular process plants, and pre-fabricated building solutions for industrial and commercial clients. Closely comparable business model to Flex Air with similar modular fabrication approach and customer overlap.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat5 records
Key risks6 records
Key highlights6 records
Customer concentration
Flex Air social profiles
Digital presenceFlex Air financial estimates
Financial estimateRevenue estimate
Valuation estimate
Flex Air leadership team
Management profileNumber of profiles
Profiles2 records
Flex Air funding detail
Funding detailFunding overview
Funding rounds
Investors
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
Flex Air M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about Flex Air
What does Flex Air do?
Flex Air designs, engineers, and manufactures custom modular air handling units (AHUs), modular mechanical systems (boiler plants, chiller plants, HVAC skids), and modular electrical substations in a controlled factory environment, then ships them to customer sites for rapid installation. The company sells directly to enterprise customers including automotive OEMs, pharmaceutical manufacturers, data center operators, healthcare systems, and universities across North America.
Is Flex Air a public or private company?
Flex Air is a private company. It is classified as family owned and is currently operating.
When was Flex Air founded?
Flex Air was founded in 2015. It employs 51 to 100 people.
Where is Flex Air based?
Flex Air is headquartered in Fenton, United States, in the North America region.
How does Flex Air make money?
Three revenue lines are on record. Custom Modular System Sales are the primary driver. The others are engineering and Installation Support Services and preventative Maintenance and Restorative Services.
Who are Flex Air's main competitors?
Broad incumbents on record are Carrier Global, Trane Technologies, Eaton, Daikin Applied, Johnson Controls (York) and ABB (Electrification). Direct peers are Vertiv Holdings, Modine Manufacturing, Kelvion and Stellar (Stellar Industries).
Does Flex Air have an API?
No public API is recorded for Flex Air.
What industry is Flex Air in?
Flex Air's product category is Industrial Modular HVAC and Mechanical Systems. Its primary akta.pro industry code is IMADANAA, Air Handling Units (AHUs) & Rooftop Units (RTUs), with a secondary code of IMAHAKAB, HVAC Equipment (Heating, Cooling & Air Handling). Its NAICS code is 333415 and its SIC code is 3585.