With Temperatures Increasing, is Your HVAC System Ready for a Hotter Future?

The summer of 2026 has delivered an unmistakable message to building owners, facility managers, and HVAC engineers across the United States: the cooling systems that were adequate a decade ago may no longer be good enough.

From coast to coast, the heat this year has been relentless. A powerful heat dome over the central and eastern United States in late June and early July locked more than 200 million Americans into days of life-threatening heat. Washington, D.C. recorded its hottest July 4th ever at 103°F. Philadelphia saw three consecutive days above 101°F for the first time in the city’s history. Atlantic City, New Jersey tied its all-time heat record of 106°F. Daily high temperature records were matched or broken more than 1,500 times in June alone, according to data compiled from NOAA weather stations.

And just as the East Coast caught a brief reprieve, a second major heat dome moved in across the West and Northern Plains – with Billings, Montana shattering its all-time temperature record in mid-July and Salt Lake City posting its second-highest reading ever. More importantly, this isn’t a one-summer anomaly. It’s a trend, and projections suggest it will only intensify.

Many Cooling Systems Just Can’t Handle this Upward Trend  

With temperatures continuing to rise, air conditioning-related energy demand in the U.S. alone is anticipated to nearly triple by 2050. For businesses of every type – office buildings, manufacturing plants, hospitals, schools, data centers, retail facilities and more – this trajectory poses a serious operational challenge.

HVAC systems designed and sized for the climates of 20+ years ago (or even 10 years ago) were engineered to handle conditions that may no longer reflect real-world peak loads. When outdoor temperatures routinely exceed historical highs, cooling systems are pushed past their intended capacity. The result is inadequate temperature control, increased energy consumption, accelerated equipment wear, and in critical environments, potential process failures, extended downtime or severe equipment damage.

The Solution: Cooling Coils that Increase Capacity

The question facing building owners, facility managers and engineers today isn’t just how to keep up with today’s higher temperatures – it’s how to build HVAC infrastructure that can handle the summers still to come.

In virtually every forced-air commercial and industrial cooling system, the cooling coils are where the actual work of heat transfer happens. Whether it’s a chilled water coil in an air handling unit, a direct expansion (DX) refrigerant coil in a rooftop unit, or a process cooling coil in an industrial application, the coil is the heat exchanger that extracts heat from the airstream and moves it out of the conditioned space. When a building’s cooling system is falling short, the coil is very often at the center of the problem – and potentially the center of the solution.

New commercial air handling units typically come with standard OEM coils that are designed to meet the most basic application parameters. But as outdoor temperatures rise and internal heat loads grow, those standard coils can fall short. To avoid completely replacing an AHU, a much more cost-effective option for increasing cooling capacity in an existing system is to invest in replacement coils with a much more sophisticated approach to coil design and selection.

The Custom Coil Advantage

When facing these types of challenges, working with a custom coil manufacturer becomes particularly valuable. At Marlo, every coil we build is engineered to order – not pulled from inventory. That distinction matters enormously when the application demands performance beyond what standard coils can deliver.

Marlo’s engineering team uses advanced thermal analysis tools, including our own MarloMetrics® software and other applications when required, to accurately model airflow patterns, predict pressure drop, and calculate heat transfer performance under specific operating conditions. We simply don’t make “standard” coils. Rather, Marlo engineers start with what the application actually requires – and then design a coil to meet those parameters precisely. Some of our many design strategies for improving cooling performance can include:

• Circuit configuration and circuiting density – to extract more cooling from the same coil face area.
• Fin geometry – Marlo offers three fin designs to balance heat transfer against pressure drop – something a one-size-fits-all coil cannot do.
• Tube row count and fin spacing – can be customized to match the specific performance requirements of the application.
• Coil configuration – to improve cooling performance in a specific existing space.

Material Selection: Another Custom Advantage

One aspect of coil design that often receives less attention than it deserves is material selection, which can have a meaningful impact on coil performance, as well as long-term durability. The vast majority of commercial cooling coils are built with copper tubes and aluminum fins in a galvanized steel casing. While that combination works well in most standard applications, alternative materials can offer significant advantages in certain environments.

At Marlo, we have extensive experience designing and building coils with non-standard metals – due in large part to our work with the U.S. Navy, where more robust materials are often required. Some examples include:

• Copper fins – offering superior thermal conductivity compared to aluminum.
• Stainless steel tubing – the right choice for corrosive environments, allowing the coil to sustain its rated performance far longer than one compromised by corrosion.
• Copper-nickel alloys – for tube and header construction, they also offer excellent resistance to corrosion – again protecting long-term performance.
• Aluminum tubing – offers an ideal alternative for specific applications, and offers reduced weight.
• Heavy-gauge galvanized or stainless steel casings – ensuring structural integrity of the coil’s service life, preventing mechanical deterioration that can reduce airflow and cooling effectiveness.

Ready for the Challenges Ahead

The summer of 2026 has made it clearer than ever that extreme heat is an increasingly common operating condition that presents challenges for buildings and facilities that depend on reliable cooling for occupant comfort, process integrity, or equipment protection. This new reality demands a closer look at whether existing cooling systems are truly up to the task.

For building owners or managers with systems that are struggling to maintain setpoints during extended heat events, custom replacement coils – engineered to deliver more capacity within the existing physical envelope – can not only be the solution, but also a cost-effective alternative to a full system replacement.

Marlo’s decades of experience as a custom coil manufacturer means we deliver engineered-to-order cooling coils, built with the right design, the right materials, and the right performance specifications for the actual operating environment. That makes us an ideal partner for businesses looking to build more cooling capacity, as well as resilience, into their existing HVAC systems.

To learn more about how Marlo can help design a higher-performing cooling coil solution for your application, contact your local Marlo representative.