Each year, the AHR Expo acts as a window into the future of the HVACR industry. In 2025, that window opened wide to reveal a transformation not only in technology and refrigerants, but in the very bones of the systems we rely on to keep buildings, equipment, and people comfortable and productive.
While much of the industry buzz at this year's Expo centered around new refrigerant blends, cold-climate heat pumps, and innovations in smart controls, one of the most impactful shifts was the simple design of copper tubing.
Many manufacturers are now building heat exchangers and coil systems around 5mm and 7mm copper tubes, moving away from traditional 3/8-inch and larger formats. What started as an engineering tweak has become a structural shift—one that's reshaping performance, sustainability, and product design across HVAC, refrigeration, and even data center infrastructure.
Held in Orlando, the 2025 AHR Expo brought together more than 50,000 attendees and nearly 1,900 exhibiting companies worldwide. There was a clear and consistent trend across the 500,000+ square feet of exhibit space: small-diameter copper tubing is a mainstream design strategy.
The message was unmistakable, from Midea's "M Thermal Arctic" ATW heat pump using 7mm copper to Daikin's commercial rooftop units incorporating 5mm coils. OEMs across the residential, commercial, and industrial sectors embrace smaller copper as a standard.
1. Efficiency Through Geometry
Smaller tubes offer a greater surface-area-to-volume ratio, which improves heat transfer. As the refrigerant flows through these narrower tubes, it maintains better contact with the tube wall, enhancing overall thermal exchange.
Residential Multi-zone system using R454B.
2. Lower Refrigerant Charge
With global regulations shifting toward low-GWP refrigerants like R32 and R454B, system designers are under pressure to reduce charge volumes. Smaller tubes mean less internal
volume, allowing OEMs to meet regulatory requirements while delivering high-performance systems. Residential Multi-zone system using R454B.
3. High Strength, Small Scale
Copper maintains excellent mechanical properties even at reduced diameters. In CO₂ systems requiring high-pressure performance, 5mm copper tubes like those in LU-VE Group's gas coolers are rated up to 130 bar, with no need for high-strength alloys.
While aluminum microchannel coils have gained attention, particularly for their weight and cost advantages, the 2025 report clarified that challenges remain, especially for evaporator applications.
Sanhua and Climetal, two major players in aluminum coil technology, acknowledged ongoing difficulties in developing vertical fin evaporators. Despite multi-million-dollar R&D investments, their prototypes have not achieved widespread success.
Copper, by contrast, continues to deliver consistent performance, formicary corrosion resistance, and superior brazability—especially in hybrid applications like dual-fuel systems and cold-climate heat pumps.
As sustainability mandates and urban infrastructure constraints shape the future of data centers, copper's thermal performance, material recyclability, and space efficiency will continue to make it the material of choice.
Examples from Leading Brands
A Strategic Opportunity for OEMs
This trend presents a rare opportunity for manufacturers and design engineers: A way to deliver better performance and sustainability without reinventing the wheel.
Small-diameter copper tubes enable:
Whether you're developing VRFs, residential heat pumps, or data center solutions, now is the time to evaluate your approach to heat exchangers.
Copper's Compact Future
It's often the smallest design choices that unlock the most significant results. As the HVAC and cooling industries evolve under the weight of global decarbonization, electrification, and digitalization, copper continues to rise, not just in durability or efficiency, but in elegant adaptability.
CDA is helping OEMs, engineers, and product teams navigate this shift with technical support, material expertise, and real-world data on 5mm and 7mm copper coil performance.
CDA also offers tailored support for your projects. To learn more about what it means to partner with CDA, visit https://info.copper.org/how-to-partner-with-cda.