As homeowners work to stay cool, HVAC contractors face a surge in service calls, emergency repairs, and preventive maintenance requests. 

Consumer demand reflects the trend. According to Thumbtack’s third annual Sweatiest Cities Report, requests for cooling-related home projects — including air conditioner repairs, installations, thermostat upgrades, and fan installations — rose sharply this summer. Atlanta led the rankings, followed by Austin, Washington, D.C., Charlotte, and Baltimore, while several Sun Belt cities, including Houston, Orlando, Raleigh, and Tampa, posted year-over-year increases exceeding 20%. 

For contractors, the increased demand is more than another busy summer. It is another indication that prolonged periods of extreme heat are reshaping peak cooling season, requiring technicians to prepare for heavier workloads, changing equipment demands, and customers looking for ways to improve reliability and energy efficiency. 

Extended periods of extreme heat are pushing HVAC systems harder, increasing equipment failures and forcing technicians to rethink everything from maintenance schedules to truck inventory. 

“Extreme heat used to be an event. Now it’s the season,” said Andrey Yev, president of Alpha Mechanical, based in Sacramento, California. “When it’s 108°F four days straight, air conditioning stops being a luxury and becomes a necessity.” 

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Yev said today’s prolonged heat waves are exposing problems that often develop months earlier. An undercharged refrigerant system, restricted airflow, dirty condenser coils, or aging electrical components may operate adequately during mild weather but quickly become failures after several consecutive days of triple-digit temperatures. 

Scott Pierson, vice president of HVAC and market strategy at Parts Town, said contractors nationwide are seeing the same pattern. Longer runtimes and continuous cooling demand increase stress on systems, making midseason breakdowns more common. 

"July and August typically bring the highest cooling demand of the year," Pierson said. "Those conditions increase equipment stress and overheating risks, making systems more susceptible to breakdowns." 

Dirty coils, low refrigerant levels, worn motors, capacitors, and thermostats remain among the most common culprits, particularly on systems that have received little or no preventive maintenance. 

Rather than a single catastrophic failure, many emergency calls stem from multiple small issues compounding over time. 

Yev recommends technicians go beyond replacing the failed component by checking superheat and subcooling, measuring return and supply temperature differentials, inspecting condensate drains, and testing capacitors before they fail completely. 

“A capacitor that tests marginal during a mild week dies in the next heat wave,” Yev said. “Replacing it now is much cheaper than a Saturday-night emergency.” 

The industry’s response is changing along with the weather.  

Instead of treating extreme heat as a few isolated weeks, contractors are extending spring maintenance programs, expanding maintenance agreement schedules, and stocking trucks for a cooling season that begins earlier and stretches later into the fall. 

Pierson said preparation now extends well beyond scheduling technicians. Contractors are carrying larger inventories of high-demand parts — including capacitors, motors, thermostats, and diagnostic supplies — while dispatchers monitor inventory levels more closely as demand spikes across multiple markets simultaneously. 

Ready access to OEM replacement parts and real-time inventory visibility can make the difference between completing a repair on the first visit or returning days later while customers wait through another heat wave. 

Yev said preparation starts long before the first 100-degree day arrives. 

“Treat extreme heat as the season, not the event,” he said. “Equipment that survives one hot afternoon fails on day four of a heat wave.” 

That means moving preventive maintenance into spring, ensuring trucks carry the components most likely to fail, and recognizing that systems are now spending more time operating at or above their original design conditions. 

Contractors also say solving comfort complaints increasingly requires looking beyond the condensing unit. 

When homeowners complain that the upstairs won’t cool or the system runs continuously without catching up, Yev said the problem often lies with the building itself. Leaky attic ductwork, inadequate insulation, and air leakage can force HVAC systems to work much harder than necessary. 

“Every BTU the envelope keeps out is capacity the equipment doesn't have to produce,” he said. “Fix the ducts and the envelope first.” 

That same principle is becoming increasingly important in commercial buildings, where the building envelope — particularly the roof — can have a significant impact on HVAC performance. As cooling seasons extend and overnight temperatures remain warmer, buildings have less opportunity to shed heat, leaving systems running longer and closer to their limits. 

To better understand how extreme heat is changing building loads, ACHR NEWS spoke with Allison Anderson-Forbert, senior vice president of NanoTech’s Materials Division, whose expertise focuses on thermal performance and building-envelope solutions. 

She said building owners are increasingly recognizing that HVAC performance cannot be separated from the thermal performance of the building itself. 

“For many commercial buildings, the roof is one of the largest sources of heat gain,” Anderson-Forbert said. “Rather than viewing it solely as a maintenance asset, owners are increasingly evaluating how it can help lower operating costs, improve occupant comfort, and strengthen overall building resilience.” 

Anderson-Forbert said many HVAC systems that appear undersized today may not have been incorrectly selected when they were installed. Instead, changing climate conditions have altered the environment those systems were designed to serve. 

“Customers often call us because their HVAC system appears undersized, but in many cases it wasn't undersized when it was installed,” she said. “The climate has changed around it.” 

Reducing heat gain through the roof and other parts of the building envelope can lower the thermal load HVAC systems must offset, helping equipment operate closer to its intended design conditions. 

Solutions such as advanced roof coatings are one example of how building owners are exploring ways to reduce heat transfer without immediately replacing mechanical systems. 

The broader takeaway for contractors is that comfort issues during prolonged heat events may not always point to an equipment problem. 

Understanding how roof performance, insulation, ductwork, and air leakage influence cooling loads can help contractors identify solutions that improve system performance, reduce strain, and support long-term building resilience. 

For contractors, the challenge of extreme heat is no longer simply responding to more service calls. It is preparing for a cooling season where equipment operates closer to its limits for longer periods of time. 

Yev said the contractors best positioned for these conditions will be those who move from reactive service to proactive system management — verifying performance before temperatures peak, maintaining equipment earlier in the year, and helping customers understand the factors affecting comfort. 

“Charge and airflow verification becoming standard on every call, load calculations on every replacement, and the envelope conversation folded into ordinary service to give energy efficiency awareness,” Yev said. “The contractors who thrive will be the ones who keep people running through a heat wave, using spring maintenance, monitoring, and honest diagnostic discussions.” 

Pierson said preparation also requires operational discipline behind the scenes. With peak heat driving simultaneous increases in service calls and parts demand, contractors need reliable inventory strategies and access to the components most likely to fail under sustained loads. 

“Prepared contractors plan for unpredictable repairs before peak cooling demand arrives,” Pierson said. “That means conducting preventative maintenance, performing regular inventory checks on high-demand parts, educating customers on basic maintenance practices, and partnering with a dependable OEM parts supplier.” 

As extreme heat becomes a more permanent part of the cooling landscape, contractors will need to shift from reacting to failures to preventing them. The companies that succeed will be those that combine stronger maintenance programs, better diagnostics, smarter inventory planning, and a deeper understanding of how the entire building affects HVAC performance. 

“Extreme heat doesn’t break equipment so much as it exposes minor failures and collects on every shortcut taken in the spring,” Yev said. 

“It’s always worth remembering that an HVAC system is like a living organism,” he said. “Extreme heat doesn't break equipment so much as it exposes minor failures and every shortcut taken in the spring.”