Warm Sweater Day

Today it is Warm Sweater Day in the Netherlands, where we are all encouraged to wear more clothes and turn the heating down. I have a lot of thoughts about this, as we try to live as sustainably and circular as possible, this does make a noticable difference, also for our energy expenses. I already practice this daily and wear at least five layers in winter, so there is not more I can do to improve this.

In the end, if we use less heating, this reduces our resource consumption and it has a positive effect on the environment overall. This has an offset of course by having to wash more clothes, which also costs energy, water, and detergent. If you check your energy use you can easily see that heating a space on average will outweigh the costs of additional washing by a factor of 4-10, at least for the direct energy consumption. From a life cycle perspective, it does not include the energy needed to treat and pump the water to the washing machine, or to produce and transport the detergent. I still estimate those costs totalled would be less than increased heating.

An additional consideration is, in winter, how low can you go, and in summer vice versa if you were to wear less and not use cooling, how high can you go, while still being healthy? For several groups of potentially vulnerable people, such as older adults, children, pregnant people, and people with certain medical conditions, the temperatures cannot be too low or high, or medical conditions arise. These groups of people have a smaller acceptable temperature margin than the average population. This means that even if we use more sweaters, there is a limit. What is it?

This website selling airconditioning mentions research from the Technical University in Helsinki and the Lawrence Berkeley National Laboratory. It says for work the ideal temperature is 21-22 degrees Celsius; bathrooms 22-24, adult bedrooms 16-19 and child bedrooms 17-20. Indoor temperatures less than 16 degrees can lead to molds and asthma. Less than 12 degrees can impact the cardiovasculair system. Cold indoor temperatures can increase depression, confusion, decrease concentration, and increase chronic pain. Heat can lead to headaches, fatigue, and less concentration. The online manual VHG Het Levende Gebouw (The living building) also states that every degree over 25 and under 20 leads to a drop of 2% in productivity. This seems to be an ideal range for the average population.

We could keep our indoor temperatures around 18 degrees if we manage to dress more warmly. But this still has to be balanced with activity, to even out how warm you feel inside. We know it is healthier to not sit down for hours on end without moving, and the positive benefits of a walk, especially in nature, are proven as well. So yes, wear more sweaters to save on heating, but also move your body regularly, about every hour, and get a cup of hot water/hot drink.