Do You Know About Warm Sweater Day?

The concept is simple: Turn down the thermostat by 1 C (1.8 F) and layer up.

sweater and thermostat

Getty Images/Rosshelen

The Netherlands has a wonderful annual tradition called Warm Sweater Day, or Warmetruiendag, as it's called in Dutch. This cozy day takes place at the beginning of February, which is when the Kyoto Protocol took effect in 2005. Warm Sweater Day was initiated shortly after in 2007 by the Climate Alliance (Klimaatverbond) and has continued to grow in popularity ever since, with over 200,000 people participating last year.

The concept is simple: Participants turn down their thermostats by 1 C (1.8 F) and put on a warm sweater for the day. It may not seem like a big deal, but it adds up when practiced by a large number of individuals. The Warm Sweater Day website says that 6% of both energy and carbon dioxide emissions are saved by a one-degree-Celsius reduction. Translated from the Dutch:

"If the whole of the Netherlands burns 1 degree lower in 1 day, we will save 6.3 million kilos of CO2! If we do that for an entire heating season, we will save no less than 1 megaton of CO2!"

This year, an online vegan retailer in the UK, Shop Like You Give a D*mn, is hoping to bring Warm Sweater Day across the Channel. It has launched a campaign urging people to participate on February 5th and to raise awareness of how a small drop in indoor temperature can add up. 

Where the real improvement comes from, however, is the lasting impact of the challenge on people's behavior. Exposure to Warm Sweater Day makes people more inclined to repeat it on their own. Waste Less Planet reported, "Inquiries have shown that after participating in a Warm Sweater Day, 1 in 5 people start being more aware of how much energy they use. Many of them turned down the central heating for good, started wearing warmer clothing, or cuddled up under a blanket when watching television or reading a book."

In my Canadian house, where the thermostat sits at 65 F (18 C) during the day and dips much lower at night, every day between November and April is Warm Sweater Day. I love sweaters and don't understand why more people don't keep their houses cool so that they can enjoy the broad range of fashion options that sweaters provide. It opens an entire universe of sartorial satisfaction!

From Waste Less Planet's writeup: "The Dutch are almost unanimous in their favorite kind of sweater: 92% prefers a machine-knitted one. Nearly half wants it to have a round collar, and 77% prefers the sweater to be one color. Only 33% likes sweaters baggy and 59% wants it to be a tight fit."

I asked the Treehugger crew what their go-to sweater choices are. From commerce editor Maggie Badore: "First off, I want to say that I'm always cold and therefore love sweaters. I highly recommend layering a chunky cardigan over a tight-fitting sweater." You can see her cozied up in the picture below. The cardigan is from Amour Vert, made from ethically produced (non-mulesed) merino wool.

Maggie's sweater
Maggie shows off her favorite cardigan.

M Badore

Mary Jo DiLonardo is "more of a fleece and 3/4-zip person than a sweater wearer, probably because it's Atlanta." She's also a dedicated outfit repeater, adding, "I've worn the same plum fleece jacket for well over a decade." Other mentions included Snuggies and the fabulous knits sported by David Rose on Schitt's Creek. 

Secondhand sweaters got a few mentions. Photo editor Lindsay Reynolds wears her dad's wool sweater from Scotland on top of a Uniqlo heat tech undershirt. Personally, I'm a fan of thrifted cashmere; my go-to is a baggy men's pullover that I bought for $5 three years ago and it's the warmest, lightest sweater I own, perfect for cold, dark, early mornings when I start work before the house has warmed up.

Lindsay's sweater
Lindsay's dad's wool sweater from Scotland.

L Reynolds

You can join in the Warm Sweater fun, today or any day. Because so many of us are working from home, it's easier than ever to lower the thermostat without worrying about how coworkers may feel. Give it a try and you might just find you love feeling cozy with that extra layer. Add some socks, slippers, and a cup of tea for even more toastiness.

Read more: 7 Items to Help You Survive the Winter, According to Treehugger Editors