Why Cold Walls "Suck" Heat from Us
In a poorly insulated house with cold walls and freezing corners, there will be no real comfort. A detailed explanation of why is below
1. The main problem with cold walls and corners, as well as a cold floor, is that they create local drafts. Cold air descends along such a wall at a speed of 10-20, or even 30 cm/sec, which is enough to disrupt the thin protective layer of warm and moist air that normally protects your skin from cooling down.
More details on this can be found in the article “Thermal Comfort. Why even healthy people are better off avoiding drafts”.
2. Radiation losses are usually smaller, but can also be significant. For every 5°C decrease in wall temperature, your radiation losses increase by 7%Radiation losses are proportional to the absolute temperature to the fourth power. You then need to calculate the difference between what your body radiated and what it “received” from the wall.
Both of the factors mentioned above almost always act together, providing you with stable local cooling, especially when you spend a lot of time near a cold wall without changing positions, for example, sitting at an inconveniently located desk.
More details on why local cooling and drafts can seriously harm your health can be found in the article “Thermal Comfort. Why when your feet are frozen, your throat, joints, and kidneys hurt”.
