“In the afternoon, it gets hot at my desk… when I come to work, it’s too cold… It’s cold outside but hot inside.”
These are common office complaints – and Steve Simpson hears them year-round. He chairs the Auckland committee of FMANZ, which has more than 1800 facility manager members nationwide.
“For those people that might have a cold coming on, or their health isn’t that flash, or they like exercising during the day, or they like sitting at the window side to see the sun, there isn’t always going to be a sweet spot for those people.”
Complaints tend to happen during seasonal changes as indoor temperatures drift within the recommended ranges, says HVAC Engineering Group chairman Robert Banks.
Unsplash / Getty Images
But getting about 80 percent of staff satisfied with the indoor temperature is about as good as it gets, says HVAC Engineering chairman Robert Banks.
What’s the recommended temperature?
WorkSafe’s recommends 18-22C in winter and 19-24C in summer for indoor thermal comfort.
However, Banks says a temperature lower than 21C during winter in a space where staff are sedentary and not wearing their winter gear may mean it’s too cold. So building managers of such spaces usually follow a guidance of heating to no less than 21C in winter, as research had shown most people will find this comfortable.
Modern building systems use a “computer-controlled set point arrangement” to maintain temperatures, Banks says.
Some workplaces also ask for local thermostats that can shift a few degrees either way.
“Psychologically, people are quite happy if they can adjust it by 1 degree, [feeling it has made a difference].”
Complaints tend to happen during seasonal changes as indoor temperatures drift within these different ranges and people adjust their clothing, he says. “But people are less tolerant of overcooling than overheating, tests have shown that.”
Banks, who has designed and supervised office air‑conditioning systems, says several building design factors influence how temperature is felt, including glazing type, insulation and occupancy. For example, 10 people can give off a kilowatt of heat, so a small 10sqm meeting room may only suit four or five people to maintain temperature and air quality.
Sitting right next to the sun may mean you’ll feel hotter when the sun strikes, especially if the glazing is clear.
Unsplash / Curated Lifestyle
Why do my peers not feel as cold/hot as I do?
If you’re rushing from one meeting room to another, “your equilibrium body temperature is going to be cooler than someone who’s sitting there for two or three hours straight”, Banks says.
University of Otago public health researcher Zhiting Chen says body size, weight, composition, and metabolic rate all affect how quickly someone gains or loses heat.
Chen says research shows women, on average, prefer temperatures 1-3C warmer than men, and some studies suggest women have a narrower comfort range.
“These differences are usually explained partly through physiology. For example, women generally have a lower metabolic rate, which means the body produces less internal heat,” Chen said in an email.
“Female thermal perception may also vary across life stages and biological changes, including menstrual cycles, pregnancy, and menopause.”
Thermoregulation becomes less efficient with age, making older adults more sensitive to temperatures outside their comfort zone, Chen says. “Chronic conditions, disabilities, and some medications can also influence how people experience indoor temperature.”
University of Otago public health researcher Zhiting Chen.
Supplied / University of Otago
Who is the research based on?
Chen says many influential ‘thermal comfort’ models don’t fully capture the diversity of people’s needs. “These models were often built around an ‘average’ occupant, historically based heavily on young, healthy male adults.
“This does not mean these models are useless, but they can be limited when applied to the diverse populations who actually live and work in buildings.”
Some guidance now recognises that vulnerable groups may need narrower or more protective ranges, but most standards still don’t account for gender or broader demographic variation, Chen says.
Banks notes that while older research used clothed male mannequins, “the calibration of heat loss is prorated based on the size of the body… and all clothing can be given a clothing insulation factor”.
Does it affect productivity?
A University of Southern California study of more than 500 German students, published in 2019, found women performed better on math and verbal tasks at higher temperatures, while men performed slightly better at cooler ones. (Although the relationship between temperature and men’s performance was less pronounced.)
The authors say the findings “raise the stakes for the battle of the thermostat”.
“One of the most surprising things we learned is this isn’t about the extremes of temperature,” the study’s co-author, Tom Chang, said in a news release. “Even if you go from 60 to 75 degrees [15.5C – 23.9C], which is a relatively normal temperature range, you still see a meaningful variation in performance.”
Chang told RNZ’s Sunday Morning his research aimed to show that temperature also affected the productivity of knowledge workers or white collar workers.
Dealing with the complaints
Banks suggests a simple test: ask six nearby colleagues if they also feel too hot or cold, and report to your building manager if most agree.
If it’s too hot, don’t crank the system beyond the recommended range – it won’t work faster and may just end up using more energy instead, he says.
Steve Simpson is the Facilities Management Association of NZ’s Auckland Committee chairperson and Colliers associate director.
Supplied / FMANZ
FMANZ’s Simpson says good consultation with staff is essential, so the “outliers” don’t take matters into their own hands and disenfranchise others.
If someone is consistently too cold, consider moving them to a sunnier desk or reviewing airflow patterns, he suggests. Banks adds it may be a matter of rethinking the limitations of dress codes.
– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand