As climate change pushes temperatures higher around the world, demand for air conditioning is rising rapidly.

The International Energy Agency (IEA) estimates that energy demand for space cooling couldmore than triple by 2050, driven largely by the rapid spread of air conditioning.

But these cooling systems are a significant climate problem of their own.

Most cooling technology in use relies on vapor-compression technology, which circulates chemical refrigerants through a compressor. “The cooling sector has historically been very risk-averse,” said Berardo Matalucci, co-founder and CEO of MIMiC Systems, a Brooklyn-based company building alternative cooling technology that replaces bulky compressor units for hotels, offices and homes. “Almost every air conditioner is on 19th-century innovations.”

Jarad Mason, an associate professor of chemistry and chemical biology at Harvard University, who studies solid refrigerants for cooling systems, explained that “pretty much every air conditioner, refrigerator and heat pump that you use in the US has a vapor compression system that uses a fluorocarbon-based refrigerant.”

Those refrigerants, also known as hydrofluorocarbons, are potent greenhouse gases, “orders of magnitude (stronger) than carbon dioxide,” Mason said.

Greenhouse gases warm the planet by trapping heat that would otherwise escape into space, and even small leaks of refrigerants from air conditioners can have an outsized climate impact.

Even though these cooling systems are designed as closed loops, refrigerant leakage is widespread.

“It’s not practical at scale to make these systems leak-free, and still cheap enough to be commercially viable,” Mason said.

According to Mason, refrigerant gases, including fluorocarbon gases used in refrigerators and heat pumps, contribute around 2% to 3% of global greenhouse gas emissions, approaching the climate impact of the entire aviation industry.

Matalucci adds that, “as refrigerant escapes into the atmosphere, it also causes a lack of efficiency. So (appliances) draw more and more electricity.”

That inefficiency matters as cooling is the fastest-growing source of energy demand in the building sector, according to theIEA. It accounts for10% of global electricity demand.

Mason explained that refrigerants are increasingly being banned throughout the world, but progress is slower in the US. “Europe has switched many cooling systems to propane, which has much lower global warming potential, but it’s obviously very flammable and that creates potential safety issues.”

“Over the past few years, there has been a really strong push to try to find alternatives to compression systems,” Matalucci said.

The alternatives fall under a broad category known as solid-state cooling or alternative cooling technologies, systems that avoid refrigerants altogether.

Instead of evaporating* *and condensing refrigerant gases, solid-state systems use intrinsic changes inside solids to move heat, Matalucci explained. MIMiC focuses on thermoelectric cooling, a technology that moves heat using electrons in solid materials such as bismuth, tellurium and antimony. The company is also experimenting with alternative compounds, including silver and selenium, to drive down costs while strengthening performance.

“You don’t have volatile refrigerants that could potentially get into the atmosphere,” Matalucci said. “There are no moving parts whatsoever. Zero.” No moving parts means fewer replacement components over time, less material waste, and lower costs.

The solid-state cooling market is forecast to grow rapidly. The global air-conditioning market is valued at approximately $160 billion and is projected to reach $308 billion by 2035. By contrast, the solid-state cooling market was valued slightly under $1 billion in 2024 but is projected to grow to $4.55 billion by 2032.

According to Mason, solid-state cooling systems were developed in the middle of the 20th century but have historically been confined to niche applications like portable coolers, spacecrafts and submarines, where reliability and safety are leading priorities.

“One would be hard-pressed to find a solid-state device that’s being used at scale for air conditioning,” Mason said. Not only are solid-state devices more expensive, “one of the biggest challenges is reaching an energy efficiency, or coefficient of performance, that is comparable to existing systems,” he said.

According to data from the nonprofit, global energy systems think tank Rocky Mountain Institute, conventional air conditioners typically operate at an average coefficient of performance (COP) between two and four, with the most efficient systems reaching around five or six under optimal conditions. By contrast, solid-state cooling devices have demonstrated a wide range of COPs from below one to well above 10. Matalucci and Mason agree that most solid-state systems have yet to match the efficiencies of conventional air conditioners.

“MIMiC is increasing the efficiency of traditional solid-state technology,” Matalucci said. “We are targeting efficiencies comparable to conventional air conditioners, but in the near future, we are confident that we can surpass those efficiencies as solid-state materials improve.”

Matalucci said that the materials and manufacturing methods MIMiC is developing would drastically reduce the cost and greenhouse gas emissions of its cooling technology by lowering both the electricity required to run the systems and the emissions associated with their production.

** **“When it comes to air conditioners, we estimated emissions reductions of 3% to 20% over a 15-year timeframe” if an individual property switches from traditional air conditioning to MIMiC modules.

Currently, there are a few companies that have solid-state products on the market. Phononic, a company based in North Carolina, focuses on solid-state cooling solutions for data centers. Magnotherm, based in Germany, develops solid-state cooling technology that moves heat using magnetic fields for solutions in food-retail spaces.

Matalucci believes that a key differentiator that sets MIMiC apart in the solid-state cooling market is the modularity of its technology, enabling customization in smaller spaces. Instead of replicating the large central air conditioners typically used today for apartment and office buildings, the company has developed modular, room-scale units that can be combined as needed for individual apartments, rooms or offices. These units can be networked together into what the company describes as thermal energy networks, an approach that more closely resembles traditional radiators, fan coils or packaged terminal units than modern central AC systems.

Matalucci said these networks move heat when and where it is needed, allowing the company to target mid-to-high-rise buildings as its first application. “The more capacity you need, the more elements you can aggregate, like a Lego block,” he said.

That design has already moved beyond the prototype stage. In August 2025, MIMiC installed its first pilot solid-state climate control system in the apartment of an individual living with a spinal cord injury in Vancouver, Canada.

As of now, under low-volume production, Matalucci said that units like the one in Vancouver cost around twice as much as conventional compressor systems. “While this is still in line with premium products, we know that we have to bring down the cost to make it accessible for mass adoption. This is why we are investing heavily in R&D to reduce the material and manufacturing costs,” he said.

Solid-state systems require no refrigerant charging, no compressors and far fewer mechanical components that can fail over time. Matalucci estimates this could translate into “a 10% to 15% reduction in the cost of ownership” for households, while eliminating refrigerant-related emissions entirely.

Matalucci said that MIMiC is working toward making its units commercially available and is discussing pre-orders with early adopters. “Our goal is to have a first production run by early next year, hopefully sooner,” he said.