Winter is coming...
It is finally that time of year where scarves, beanies, and anorak jackets are more than just a fashion statement. While Northern California does not get as cold as other regions, like the East Coast (thank goodness!), the chilly weather can still be difficult to adjust to for those of us used to the sunny California weather.
We often receive feedback on TherMOOstat wondering why it's cold inside during the summer months, and vice-versa in the winter. We read all of your comments, and are using them to improve how we heat and cool our campus buildings. Where do we start? Our engineers are very familiar with the American Society of Heating, Refrigerating and Air-Conditioning Engineer’s (ASHRAE) standards for heating, ventilation and air-conditioning (HVAC) systems, and use these guidelines as a starting point for air temperature set points in campus buildings. If you are having a hard time adjusting to the change in weather and adapting to indoor temperature, check out our tips and the science behind why they work!
Fun Fact: the TherMOOstat comfort scale is a variation on the ASHRAE thermal sensation scale
To begin exploring the science of comfort, begin by considering that thermal comfort is dependent on different factors:
- metabolic rate
- clothing insulation
- air temperature
- radiant temperature
- air speed
Since metabolic rate and clothing insulation are within your control, we’ll go a little more into detail on what you can do.
What is metabolic rate?
Metabolic rate is your body’s internal production of heat, but we are looking more specifically at your activity level. This rate is measured in Watts per meter squared (of body surface) or W/m2 .
To put this in perspective:
- sitting and typing is about 55-65 W/m2
- driving is about 60-115 W/m2
- dancing is about 140-225 W/m2
- running is over 260 W/m2
So how can you use this knowledge to keep warm this winter?
If you are feeling a bit chilly in your building, take a break and go for a walk. Walking at an average human walking speed has a metabolic rate three times as high as sitting still. So even though it's cold outside, a walk can actually heat you up and you'll feel great when you get back to your desk.
What is clothing insulation?
When the weather gets cold, people tend to add on layers to keep warm. However, they don’t think much about the science behind it. Clothing provides heat insulation, and each article of clothing has a clo value, which is the unit to measure the thermal insulation of a clothing ensemble/outfit.
Clo of 0 corresponds to a naked person
- Clo of 1 corresponds to the insulating value of clothing needed to maintain a person in comfort sitting at rest in a room at 70 ℉ with air movement of 0.1 m/s and humidity less than 50%
To put this in perspective:
- long sleeve dress shirt = 0.25 clo
- thick trousers = 0.24 clo
- long-sleeve thick sweater = 0.36 clo
- boots = 0.10 clo
How can you stay warm with clothing insulation?
If you’re wearing thick layers, you’re doing it right! Thicker layers do make a difference — wearing thick trousers, a long sleeve dress shirt, a thick sweater and boots adds up to around .95 clo. The key word here is layers, especially if your temperature fluctuates throughout the day. Just a thin sweater can add about 30% more clo to your outfit, (explaining why your mom always asked if you had a sweater with you when you were leaving the house!)
The air temperature, radiant temperature, air speed and humidity are harder for building occupants to control in commercial office or communal spaces. The best way for you to influence these areas of thermal comfort is to let us know how you think the space feels on TherMOOstat.