Most people sleep, eat, work, play and relax behind four walls. We spend 90 per cent of our time indoors, yet our awareness about our indoor environment is usually limited to adjusting the radiator a bit and airing out every now and then.
"Poor indoor environment is a huge problem. People worry more about outdoor air pollution than indoor air quality, even though we spend most of our time indoors. But if you have a good indoor environment, you can focus on the things that matter and not complain about whether it's too hot or you have cold feet," says Davide Cali.
He is a senior researcher at DTU Compute and is the founder of DTU spinout Climify, a consulting and software service that municipalities and companies can use to better understand and control the indoor environment in their buildings.
Climify is primarily based on tangible data from smart sensors such as temperature, humidity, CO2 concentration, light incidence, presence and whether the windows are open or closed.
But data only tells part of the story, so Climify adds user feedback using an app. Here, the users of a room can report if they think it's too cold, too hot, too stuffy or drafty. Climify uses this information to adjust the indoor climate to suit.
"It's about getting a clear picture from objective data, but depending on where you install a sensor in a room, it can measure between 14 and 24 degrees if it has poorly insulated outer walls and windows. So you can't rely on the specific data alone, and therefore we need feedback from the users," says Davide Cali.
Headaches and difficulty concentrating
Studies have shown that humans perform worse in poor indoor climate and it can worsen our ability to solve problems by up to 30 per cent.
"For instance, as shown by a study from DTU Sustain, if the students in an elementary school lose 13 per cent of their brain capacity due to the indoor climate, then this corresponds to them having lost a whole year during their education," says Davide Cali.
Poor indoor climate can lead to headaches and difficulty concentrating as there can be everything from pollution to high CO2 levels or mould in the air. According to Davide Cali, good indoor climate is primarily about having the right balance between the room and the surroundings outside.
"And it's actually not the air temperature, but rather the wall temperature, that determines whether you feel too cold or hot," says Davide Cali.
So even if the air is, for example, 21 degrees, you can freeze if you sit next to a drafty window, or you can be sweaty if you're seated by a wall with a heating pipe running through, even if the room is otherwise cool.
Humidity also plays a role, and if the air is too dry, it can cause dry eyes and throat and increase the risk of spreading viruses, while too much humidity can affect the immune system. The CO2 content in the air is also essential, as it signals whether air is being circulated enough as we exhale CO2.
