Revolution of the Room Thermostats: The Cheaper Way to Keep Your Home Comfortable

Keeping indoor spaces comfortable is important not just for our health and happiness but also for saving energy. Room thermostats today measure only the air temperature, but that doesn’t give the full picture of how warm or cool we feel. That’s because we also feel heat radiating from the walls, ceiling, floor, and furniture around us. This is called the mean radiant temperature, which is a measure of how much heat is radiating from the surfaces around us. Until now, it has not been possible to measure it easily and affordably. A new study, available here, has now found a way to do just that using simple, low-cost sensors. Their breakthrough could change the way we manage comfort and energy use in our homes and offices.

Dr. Fatih Evren of Pacific Northwest National Laboratory, formerly with the University of Minnesota Twin Cities, developed this new method. His work was published in the science journal Nature Communications. He used low-cost thermal sensors, which are small devices that detect temperature by sensing infrared radiation, and developed a way to turn the readings into a clear picture of how temperature is distributed across a room. The new method was tested in different real-life rooms and proved to be both dependable and accurate. It offers a simpler and more affordable solution compared to older, more complicated tools.

Dr. Evren ran tests in a range of rooms, including bedrooms and offices, under different heating conditions. The method was able to measure the warmth people feel from surfaces with very little error. Unlike traditional tools like black globe sensors—round devices used to estimate radiant heat but known for being slow to respond and expensive—this new approach worked well even when only one or two sensors were used. This makes it especially useful for everyday spaces like homes.

The key idea is simple: tiny thermal sensors are placed on the walls of a room to take temperature readings. These readings are then turned into a heat map, a visual representation showing how heat is distributed in a space and how warm or cool the room’s surfaces are. From this, the average radiant temperature can be determined. As Dr. Evren explained, “The method agrees with reference measurement within a small margin and outperforms traditional black globe sensors.” He added, “It eliminates the need for pan-tilt mechanisms and other auxiliary hardware, no moving parts or extra equipment, making it suitable for integration into standard thermostats.”

The method worked well in a variety of room types and situations—whether the room was empty or filled with furniture, sunny or shaded, or using different kinds of heating. It could detect even small differences in heat throughout the space, something older methods often missed. “Results show that the difference between the black globe measurement and the reference increased as incoming solar radiation increased,” explained Dr. Evren. This shows how the new method offers better performance in rooms that get a lot of sunlight.

This innovation could lead to smarter heating and cooling systems. By giving thermostats the ability to “feel” the same warmth we experience from nearby surfaces, these systems can adjust more accurately and efficiently. As Dr. Evren explains, “The ability to measure thermal comfort accurately without direct contact opens up new opportunities in building design, maintenance, and occupant interaction with their environment.” This could help save energy while making our homes and offices more comfortable. In short, the method brings together comfort and sustainability in a way that could benefit many types of buildings.

Journal Reference

Evren F., Biswas S., Graves R. “Measuring mean radiant temperature for indoor comfort assessment using low-resolution optical sensors.” Nature Communications, 2025; 16:1215. DOI: https://doi.org/10.1038/s41467-024-55122-z

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