Do Women Need Warmer Temperatures Than Men?
Oh, how the news media love the “thermostat wars” between men and women. It’s a good source of stories based on conventional wisdom and the occasional (faulty or incomplete) research paper. The utility companies want in on the action, too. I’ve seen television ads for gas companies trying to convince viewers that just switching fuels will eliminate the battle over the thermostat. But do women really need warmer temperatures than men?
Guess what. The idea that mean and women have widely different internal thermostats is dead wrong. Let’s clear this up with the summary from the ASHRAE Handbook of Fundamentals. Based on many decades of research, they say:
The experiments show that men and women prefer almost the same thermal environments. Women’s skin temperature and evaporative loss are slightly lower than those for men, and this balances the somewhat lower metabolism of women. The reason that women often prefer higher ambient temperatures than men may be partly explained by the lighter clothing often worn by women.
The image above of two newscasters talking about the “Battle of the Thermostat” couldn’t make the point any better. The man is wearing a button down shirt, tie, and coat (and probably an undershirt as well) while the woman is a wearing a sleeveless blouse.
So, the next time you’re in a room with a man who happens to feel warmer than a woman, don’t automatically jump to the conclusion that it’s simply because he’s a man and needs lower air temperatures to feel cool enough. When you account for all of the factors of comfort, both personal and environmental, the research is clear. So, do women need warmer temperatures than men? No.
Note: If you’d like to dive into this topic and really learn how to apply the principles of thermal comfort to buildings, get yourself a copy of Robert Bean’s free book, Thermal Comfort Principles and Practical Applications for Residential Buildings. (Yes, it’s free!)
Allison Bailes of Atlanta, Georgia, is a speaker, writer, building science consultant, and the founder of Energy Vanguard. He has a PhD in physics and writes the Energy Vanguard Blog. He is also writing a book on building science. You can follow him on Twitter at @EnergyVanguard.
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“The reason that women often prefer higher ambient temperatures than men may be partly explained by the lighter clothing often worn by women.”
Or put another way: The reason that men often prefer lower ambient temperatures than women may be partly explained by the heavier clothing often worn by men.
Touché.
I think that women prefer slightly warmer temperatures because they have a higher surface-to-volume ratio 😉
I’m not gonna touch that one, Roy. :~)
Allison: I just kind of threw that comment out there as an initial thought, but the more I think about it, the more I think it has merit. I have reviewed past literature on thermal modeling of the human body by Fanger, Gagge, and others. People generate heat internally due to metabolism and the amount of that generation primarily depends on activity level and the mass or volume of the body (assuming density is constant). People have to expel all of that internally generated heat to the ambient in order to maintain a constant body temperature. Sensible heat transfer to the ambient depends primarily on the U-value (clothing level and air velocity), the surface area, and the temperature difference. If you write out all of the equations, you will see that the required ambient temperature to maintain this heat balance will depend on the surface-to-volume ratio (dissipated heat to generated heat) among other things. Since a sphere has the lowest surface-to-volume ratio, it would mean that people who are more spherically-shaped prefer cooler ambient temperatures. That seems to be true. Do women generally have higher surface-to-volume ratios? It seems like it, but more study is needed.
Roy, early on you said “assuming density is constant.” I’m pretty sure that’s not the case, though. Women have a lower density than men, so mass probably would be a better quantity to use. And then there’s the ASHRAE statement, which says, “Women’s skin temperature and evaporative loss are slightly lower than those for men, and this balances the somewhat lower metabolism of women.” Wouldn’t the lower metabolism also balance out the higher surface-to-volume ratio, if it is higher?
People are mostly water. Bone is a little denser, fat is a little less dense. Skinny people do tend to sink in a pool and fat people tend to float, but I still claim the differences are small. I am not sure about the other factors, other than my wife has cold hands.
It gets more interesting when you talk about the elderly. I worked in a nursing home and we used Trane Summit for automated temp controls. Most rooms were between 75-77 but 1 in particular was at 83. This guy wore sweats and a blanket all the time. I think only 1 or 2 rooms were below 72-73 but the common areas were at 74 I think. The system worked great after all the repairs were done after I took over maintenance there.
My wife is very particular about temps also, she never complains about being too hot unless shes sleeping. She also has Raynaud’s disease so she feels cold at 75 easily. But even with my AC being a dehumidifing beast I still keep the house at 73 during the day and a70 when we sleep.
Shae, yes, our thermoregulation definitely changes as we get older. I don’t get cold nearly as easily as I used to. And a few years ago, my wife’s stepdad needed his house very warm. If the thermostat was set below 78° F in winter, he’d complain. I learned to dress as lightly as possible when I’d go over there.
I don’t think that the issue is just related to the weight of the clothing. The number of layers of clothing may also be a factor. We are also told to wear winter clothing in layers and I subscribe to that recommendation. Part of the layer recommendation might be related to being able to take off layers to adjust to varying thermal conditions. One the other hand, I think that layers help to trap more air around a body, providing more insulation. So, don’t forget the layers of clothing.
Matt, yes, you’re absolutely right. The ASHRAE thermal comfort standard (55) ascribes “clo” values for different types of clothing as well as ensembles, which includes the insulating quality of the air when you have layers of clothing on.
Seasonal clothes. After getting married it really confused me that my wife would reorganize all of the clothes based on the season. I had to tell her to stop touching my clothes because I don’t have seasonal clothes. A winter coat and snow boots yeah, but that’s it. She has drawers of clothes that need to get swapped out based on the season.
Then I noticed my co-workers in the spring. The weather warmed up and the women wore more dresses and summery type outfits. They dressed for the weather. Lighter clothes for warmer weather. And then they would complain about freezing in the office. Which always seemed odd that as the weather warmed up, the cold complaints increased. But that’s because the outfits changed.
I might suggest that temp settings could also be seasonal.
I hear these statements about women being more sensitive to cold. But, I never see men out on frigid days in skirts or dresses. Thankfully, women now wear clothing more befitting the colder conditions, but not all of them and not all of the time. I don’t see men donning skirts or dresses either – well, except maybe for kilts.
Seasonal temperature preferences is worthy of its own article. In my experience, most people set the t’stat lower in winter than in summer. In fact, most thermostats enforce a minimum ‘dead band’ between cooling and heating setpoints to prevent control conflicts in Auto changeover mode.
I think there’s more to this seasonal differential than clothing. The body re-adapts to some extent, and I think a lot depends on what we become accustomed to. I encourage clients to take advantage of our ability to adapt to save energy. Over the years, I’ve intentionally extended my comfort range to 77-78 in summer and 69-70 in winter. I will be entering my eighth decade at my next birthday, so I’m wondering if my winter temperature preference will start climbing.
On a related topic… many people prefer lower temps while sleeping, especially in winter when blankets provide warmth. I’m curious how many people I turn down the AC at night. Personally, I have to reduce the master zone to 73 while sleeping, even with the ceiling fan. Unfortunately, I’ve not been successful at persuading my body to adapt to anything higher.