Have you ever wondered why an office, apartment building, or public space can feel too hot one day and too cold the next, even when the heating system is running?
According to researchers at KTH Royal Institute of Technology in Sweden, the problem may be that most buildings rely on a surprisingly simple rule: they adjust heating based mainly on the outdoor temperature.
While outside temperature is important, it is far from the only factor that affects indoor comfort.
Sunlight streaming through windows, the number of people inside a room, and the amount of fresh air entering through ventilation systems can all have a major impact on how warm a building feels.
Researchers have found that taking these factors into account can significantly improve comfort while reducing energy use.
The team tested a new heating control method in a six-story commercial building in Sweden. Instead of relying only on outdoor temperature, the system also considered sunlight, occupancy, and airflow.
The idea was simple: when the sun naturally warms a room, the heating system reduces the amount of hot water flowing through the radiators.
When more people enter a space and generate body heat, the system adjusts again. If ventilation brings in cooler outdoor air, the heating system increases output to compensate.
The approach acts like a smarter version of traditional heating controls, but without requiring complicated artificial intelligence or powerful computer systems.
The researchers monitored the system for a year in a 10,000-square-meter environmentally friendly office building. The results were impressive. The percentage of time that indoor temperatures remained within a comfortable range increased from about 60% to more than 90%.
Temperature fluctuations were also greatly reduced. Deviations from the ideal indoor temperature dropped by 73%, meaning occupants experienced a much more stable indoor environment.
At the same time, energy consumption fell by around 10% to 13%. Carbon emissions were reduced by roughly 9%, while operating costs decreased by about 8.5%.
The biggest savings occurred during spring, when outdoor temperatures often change rapidly. During these transition periods, the researchers estimated that energy savings could reach between 56% and 70%.
One reason the system could be widely adopted is that many modern buildings already collect some of the necessary information. Sensors often monitor sunlight and ventilation, while occupancy can be estimated through carbon dioxide levels, ventilation demand, or daily schedules.
According to the researchers, this means many buildings could benefit from smarter heating controls without major renovations or expensive new technology.
The study suggests that reducing energy use and improving comfort does not always require advanced artificial intelligence. Sometimes, a better solution comes from using the information buildings already have and making heating systems respond more intelligently to the way people actually use indoor spaces.
