In 2025, U.S. researchers developed an air-conditioning system that stores cooling in a salt solution; a Miami simulation projected a 93% cut in peak electricity demand

Anyone who has been in a situation where they received warnings about rolling blackouts or texts saying "Set your thermostat at 78 degrees" during a heat wave has experienced this firsthand: air conditioners in America don’t just cool down houses; they also put a huge strain on the grid every summer.

According to a September 2025 press release from the National Renewable Energy Laboratory (NREL), researchers at NREL, in collaboration with Blue Frontier Inc., developed the Energy Storing and Efficient Air Conditioner (ESEAC), a system designed to store energy for cooling rather than drawing most of its electricity during peak-demand periods. In a year-long simulation of a 20-ton ESEAC system in Miami, Florida, the technology reduced peak electricity demand by 93%, cooling-related electricity use by 38%, and annual electricity costs by 45%.

Why your thermostat is not so innocent


The air conditioner is among the most significant factors driving electricity demand during hot summer periods in America. The International Energy Agency states that in the hottest regions, cooling can account for more than 70% of peak electricity demand.

Also, according to the U.S. Energy Information Administration, the largest hourly electric consumption in America occurs in either July or August because of everybody running their air conditioning at the same time.

So how does saltwater actually fix this?

NREL's Energy Storing and Efficient Air Conditioner (ESEAC) does not simply rely on a conventional compressor to provide cooling whenever electricity demand is at its highest. Rather, the system separates a dilute salt-based liquid desiccant into a concentrated solution and pure water, stores those fluids, and later uses them to cool and dehumidify air while avoiding compressor use during peak-demand periods.

Eric Kozubal, senior engineer at NREL, said that this approach to cooling systems is “a complete rethinking of how we condition air—and when we use electricity to do it.” This reframe is precisely the point of the innovation: instead of drawing heavily from the grid when electricity demand is highest, ESEAC shifts most of its electricity use to periods when rates are lower or renewable energy is available. The numbers from the Miami simulation are striking. A 20-ton ESEAC system showed a 93% reduction in peak electricity demand, a 38% reduction in cooling-related electricity use, and a 45% reduction in annual electricity costs. NREL estimated that, over 15 years, those savings could amount to $165,000 per unit. The saltwater-and-pure-water storage approach was also estimated to cost roughly 10 times less than battery-based energy storage.

The scepticism and the bigger picture

Healthy skepticism is in order here. This is a commercial HVAC technology designed for commercial buildings, rather than a retrofit for your studio apartment’s window unit. NREL says ESEAC systems are being installed at sites including an IMAX theater, university campuses, hospitals, a restaurant, a grocery store, and U.S. military facilities. NREL also describes Blue Frontier as commercializing the technology, so “commercially viable” is better understood as a technology being commercialized and deployed, rather than a claim that it is already a mainstream replacement for conventional residential air conditioners.

The early installations are encouraging, but longer-term real-world performance will still matter. A technology can perform impressively in simulations while facing different challenges when exposed to actual buildings, maintenance requirements, utility tariffs and years of extreme weather.

Nevertheless, when we consider that extreme heat is driving higher cooling demand and putting additional pressure on power systems, having an air conditioner that can shift much of its electricity consumption away from the grid’s most stressed periods is quite exciting. This does not mean that it will solve all the problems that exist in America's energy infrastructure. It simply means that some of the smartest solutions to rising cooling demand may involve changing not only how efficiently we cool buildings, but also when we draw electricity from the grid.