18 Nov

It pays to pay more attention to temperature

Last week I had a great conversation with Roger Whitlock at Hoare Lea consulting engineers which raised an important question.

What’s the most important problem with poorly performing HVAC? Nobody likes wasting energy, but with energy bills at less than 5% of most companies’ revenue, it’s not that big a deal, right?


Because it turns out that a poor environment, particularly poorly controlled temperature, has a direct impact on productivity. And thus on the bottom line.

This is not new news. Studies since the 1970s have consistently demonstrated a link between performance and temperature.

Some highlights:

Study 1 – A 2004 study in a call centre showing that temperatures above 25.4°C had the largest impact on productivity, beyond ventilation, CO2 levels and even staffing and shift length1

Study 2 – A 2009 laboratory study used a range of neurobehavioural tests to try and dig into the effects of temperature on more complex cognitive skills. The study found that motivated participants can maintain productivity for short periods (30 minutes) over temperature ranges between 19° – 32° c, and that moderate warmth can affect mental performance in some tasks, while cold temperatures can affect physical performance in other tasks.2

Study 3 – A 2004 office study showed a steady increase in keying (typing) rates from 20° – 25° and a decrease in errors.3

One temperature to rule them all? 

A 2011 meta analysis of these papers and others shows a steady and pretty consistent relationship between workplace temperatures and loss of productivity, with a broadly neutral effect between 20 and 23°c and a loss of about 1% of productivity for every degree either side of 20 – 25%

Temperature’s impacts on productivity come in a range of effects – from routine tasks taking longer with more mistakes, all the way to increased rates of absenteeism.

So if you put all of these studies together do they give the final word on what is the best temperature for workplace productivity?

Nearly – it seems there is a pretty narrow band where optimisation is likely to happen. They certainly make a strong case for taking temperature very seriously in any workplace, along with other factors in comfort like lighting, airflow and humidity. An important point here is that the subjects in most of these studies were properly randomised – different genders, wearing a range of clothing – meaning the results should carry over into a normal working population.

There’s a couple of points that aren’t clear yet. First the effect of acclimatisation. Does the external weather tend to increase peoples’ tolerance for higher or lower temperatures? With results from Helsinki to Florida, there does seem to be a small effect.

Secondly does this effect apply to all tasks? Many of the studies looked at administrative tasks where it’s possible to define how long something should take and what a mistake looks like. It’s obviously difficult to design similar tests for more creative or analytical work in realistic environments. But one big anecdotal clue here – there are very few offices where individual workers have complete control over their environments. The few that there are are in places where these workers produce extremely high value output and a mistake can be very expensive indeed – trading desks for example.

Getting temperature right in the real world

How does this fit with running conditioning systems in a truly efficient manner?

In a system where heating and cooling are split, the recommendation is to run a ‘dead band’ between the heating and the cooling to avoid them fighting. The heating is turned off at 20° and the cooling comes on at 24° for example. It’s clear from the research that the tighter you can keep the dead band, the more time your colleagues will spend in the productivity sweet spot.

And a tight dead band relies on tight control to avoid clashes between heating and cooling. If sensors are drifting over time, or the thermal load is higher than the original design, then buildings can be locked into a cycle of rapid heating/cooling that gives the worst of all worlds.

Reframing the temperature conversation

Nobody sets out to make an uncomfortable workplace. However maintaining the systems that keep our work comfortable is often treated as a low priority, because 1) there seems little quantifiable payback and 2) it is sometimes difficult to measure improvements. The result is that apathy takes hold and it becomes difficult to justify investment, especially where budgets are tight.

Perhaps it is time to reframe the conversations facilities managers have with the board. By producing evidence of better productivity (or raising awareness of the dangers of lost productivity) you can start to build a serious ROI for investing in better control.

For more ideas about how to measure productivity and temperature in your building without needing a scientific research grant, head over to our LinkedIn discussion on the Corporate Real Estate group.