How come there’s a distinct difference in comfort if the temperature changes only slightly? It’s something we’ve all wondered about and that’s because the answer isn’t exactly obvious; it’s actually extremely complex! We are all very susceptible to small temperature fluctuations, so finding the right air conditioner or heat pump settings to match your comfort can be very confusing. Whether you’re inside or outside, thermal comfort depends on a lot of things, especially season, temperature and humidity. Read on to find out more about the 3-degree difference, and you’ll come away with a better idea of how to utilize your AC to cope with any variation.
Your air conditioner blasts air that’s colder than the set-point temperature you’ve chosen, otherwise it wouldn’t be able to cool the room. For example, if the relative temperature of your room is 27°C and you set your AC to 23°C, the AC will blow out air at around 18-19°C in order to cool the room. Eventually you’ll freeze, because even after reaching the set-point temperature, most air conditioners won’t stop and will continue blasting very cold air until you alter the settings yourself. The opposite happens if you’re using your AC for heating in winter; you can set the AC on heat at 25°C, but the air from the vent will be significantly higher, and probably much drier too, which makes it feel even warmer. (See below and we’ll explain more!)
Outside, there are more variables and things that may affect how you feel. Sunlight, shade, breezes or still-standing air all have an affect, as does whether you’re walking or being active vs sitting at home where you’re less likely to be doing as much. This all means that when you’re inside the environment is much more stationary, and you’re more likely to be affected by subtle changes.
This is a tricky concept to grasp! Some places, like Hong Kong, are particularly humid all year round, even in winter. When winter is humid, the damp air makes you feel colder than it really is. But, if summer is humid, you’re more likely to feel stifled and hotter than it really is. This has a lot to do with how your body regulates heat through sweating and evaporation.
Also, in summer, outdoor conditions will usually still feel very hot whether it’s 25°C or 28°C. This is because the humidity level remains pretty much the same, is higher and affects our "real feel". However, in an indoor environment with your AC on cooling, 25°C will feel much cooler than 28°C because the AC successfully removes moisture from the air.
Given that humidity levels vary in different locations, and that we all have our own personal preferences, it’s almost impossible to identify one magic set-point temperature to prevent overcooling in summer or overheating in winter. But, there are some recommended ranges:
Importantly, keep in mind that for every 1°C that you reduce your AC in winter or increase it in summer, you could reduce your energy use by 5-10%, not only saving you money but also being kinder to the environment.
At the end of the day, thermal comfort comes down to many different factors and individual preferences. A variation of only a couple degrees could mean the difference between you feeling just right or freezing cold, and what’s just right for you may not feel comfortable for the people you share a room or a home with. Thankfully, technology is improving and new air conditioners and smart home solutions are designed to adapt to subtle changes and respond to your preferences so you don’t have to keep fiddling with the settings.
Learning more about how the environment, including humidity, temperature and seasonal differences can affect your comfort means you can utilize better control and be more prepared to respond to subtle changes. Keeping your AC set-point temperature within the recommended ranges is one leading way to stay comfy and waste less, but modern solutions like Home Automation and smart AC controllers can go a long way in helping you streamline this task and make it an effortless, hassle-free part of your life.