The basement stays cool in the summer. A constant 12-15 degrees Celsius, for example. Meanwhile, upstairs, the house heats up to the point of becoming a greenhouse. Logic would dictate that this cool air be brought upstairs to cool the house, but for decades no one really thought about it. Then came... Cool down, a New York startup, and decided that the solution had been there all along.
A heat transfer system moves cool air from the basement into the living spaces and sends the heat back down to be absorbed by the ground. No external compressors, no refrigerants, no condensers. Just basic physics and temperatures that the planet offers free of charge to those who can, at six feet below the surface.
How Basement Cooling Works
The principle is super simple. The ground below 1,2 meters of depth maintains a constant temperature Between 10 and 15 degrees Celsius year-round. It doesn't matter if it's 35 degrees Celsius or minus 10 degrees Celsius outside: down there, the temperature doesn't change. The basement, with its walls and floor in direct contact with the ground, becomes a huge natural heat exchanger. Cool Down just figured out how to take advantage of this free heatsink.
The system uses a heat exchanger installed in the basement. During the day, when the house heats up, The device transfers fresh air from underground to living spaces, while excess heat is directed downward. The basement walls and floor disperse this heat into the surrounding soil. No refrigerant circulating, no energy-consuming compressors, no outdoor units buzzing on the balcony.
Sixty-seven percent savings
I wrote it out in full so it's easier to understand. Cool Down promises a 67% reduction in air conditioning use during the summer season. This isn't a theoretical estimate: the company has tested the system in hundreds of American homes. The starting price is $5.000 (about €4.600), including professional installation. The entire process takes just a few hours and integrates with existing HVAC systems or operates autonomously for homes without ducts.
The new Smart Control Unit 2025 adds features that go beyond simple cooling. Basic Heating Mode Captures and redistributes heat from wood stoves, mini-splits, or south-facing rooms. Dehumidification Mode It allows you to control the humidity in the basement as in the rest of the house. Power Boost Mode temporarily increases performance on hot days, while Eco Boost Mode maximize savings by preventing AC activation during mid-seasons.
Comparison with Italian geothermal energy
In Italy we talk about geothermal systems costing between 15.000 and 25.000 eurosVertical probes that descend to depths of 100-150 meters, sophisticated heat pumps, drilling that requires permits and geological studies. These systems can reduce consumption by up to 70%, but the initial investment remains prohibitive for many families. Cool Down plays a different game: it's not deep geothermal energy, it's intelligent exploitation of the existing underground microclimate.
Il ENEA 2024 Report on Energy Efficiency This confirms that Italians are becoming more attentive to energy consumption. 69% of homebuyers now consider energy efficiency a decisive factor. Incentives are available (50% Ecobonus for 2025, Conto Termico 3.0), but more accessible solutions are needed. The home microclimate is no longer a luxuryIt's a real necessity to ensure well-being without ruining your wallet. And we have plenty of basements, I think.
When will it arrive in Europe?
For now, Cool Down only operates in the United States. Damien Semel-DeFeo, founder of the company, said that “The Smart Control Unit puts more control and savings in the hands of homeowners”The system adapts to any climate, energy goal, or home configuration. It even works for homes without ducts, serving as a standalone central cooling system.
It remains to be seen if and when this solution will cross the Atlantic. European homes have different layouts, basements are less common but exist, and regulations vary from country to country. But the principle remains valid: Under every house with deep foundations there is already a natural cooling sourceIt just takes someone who decides to use it instead of fighting it with energy-hungry compressors that heat the outside while cooling the inside.
The basement has always done its job quietly. Now someone's given it a promotion.
