What heat stress is costing your worksite
Heat slows people down long before anyone calls in sick. Answer three questions and see an indicative annual figure, built on Australian research. No revenue, wages or financials required.
People who work outdoors, in vehicles, or in hot indoor spaces.
Roughly how physical is the job?
Sets the typical number of hot days and how hot they get.
Adjust assumptions
Indicative estimate only, not a heat-stress audit. Figures use published exposure-response research and conservative defaults. Actual loss varies with humidity, shade, hydration, acclimatisation and shift timing.
Why heat slows your crew down
Heat does not wait for someone to collapse before it costs you. Output starts to slip well before that. Research built on Wet Bulb Globe Temperature, the heat measure used in occupational health and in ISO 7243, shows work capacity holds steady until conditions pass a threshold of about 25 to 27 degrees WBGT. Past that point, people slow down, take more breaks and make more mistakes.
Field and manufacturing studies put the drop at roughly 3 to 8 percent for every extra degree above that threshold, and the effect grows with how physical the job is. Source: exposure-response research summarised in Kjellstrom et al. and related field studies. On a genuinely hot day, a labouring crew can lose a large share of its effective output to heat even when nobody reports feeling unwell.
What heat costs Australian workplaces
One of the most cited Australian studies, by Zander and colleagues in Nature Climate Change, surveyed 1,726 workers and put the cost of heat at about US$655 per worker each year through absenteeism and reduced performance. Across the workforce that came to roughly US$6.2 billion, or between 0.33 and 0.47 percent of GDP.
Heat also drives injuries. Safe Work Australia records around 1,774 accepted workers compensation claims linked to heat exposure between 2009 and 2019, the large majority among outdoor workers. Research published in Safety Science found that hot days raise injury claims most for manual and outdoor crews, and that the effect has not eased over time. The reason is straightforward: as people overheat, concentration drops, grip and footing suffer, and mistakes rise.
What the law expects of employers
Under the model Work Health and Safety laws, a person conducting a business or undertaking has a duty to manage the risk of working in heat so far as is reasonably practicable. Safe Work Australia guidance sets out a familiar order: remove the risk where you can, for example by rescheduling heavy work to the cooler part of the day, then control what remains.
Recognised controls include shade and shelter, hydration, rest and rotation, acclimatisation, and increasing air movement with fans or cooling. This page is general information, not legal advice. Safe Work Australia is not a regulator. The work health and safety regulator in your state or territory enforces the law where you operate.
Practical ways to cut heat load on site
No single measure fixes heat. A layered approach works best, starting with the controls that remove the most risk.
- Reschedule the heavy work. Move the most physical tasks to the cooler parts of the day, and pause outdoor work in extreme heat.
- Add shade and shelter. Get crews out of direct sun and radiant heat wherever the task allows.
- Keep water close. Easy, frequent access to cool water does more than almost anything else on a hot day.
- Build in rest and rotation. Short, regular breaks in a cooler spot let the body shed heat before it builds.
- Allow for acclimatisation. New workers, and anyone back after a week or more away, need time to adjust and should be watched closely.
- Move air across the skin. Personal cooling gives each worker airflow that moves with them, between the bigger controls above.
Personal fans are one layer, not the whole answer. They move air across the skin to help with comfort and reduce perceived effort. They are not air conditioning, and they do not replace water, rest or shade. On a worksite they work best alongside the other controls, which is also why Safe Work Australia lists air movement among recognised heat controls.
Give each worker airflow that moves with them
Our waist fans clip on at the belt for hands-free torso airflow, so the cooling goes where the work goes. Built for long shifts, with battery life sized for a full day outdoors.
Common questions about working in heat
At what temperature does heat start to reduce productivity?
Work capacity generally holds steady until conditions pass about 25 to 27 degrees Wet Bulb Globe Temperature, a heat measure that combines air temperature, humidity, radiant heat and air movement. Above that threshold, output falls by roughly 3 to 8 percent for every additional degree, and faster for heavy physical work.
How much does heat cost Australian businesses?
A widely cited study in Nature Climate Change by Zander and colleagues estimated heat cost about US$655 per worker each year through absenteeism and reduced performance, which scaled to roughly US$6.2 billion across the Australian workforce, or between 0.33 and 0.47 percent of GDP.
Are Australian employers required to manage heat at work?
Yes. Under the model Work Health and Safety laws, a person conducting a business or undertaking must manage the risk of working in heat so far as is reasonably practicable. Safe Work Australia provides national guidance, and the work health and safety regulator in each state or territory enforces the law.
Do personal fans help with heat stress at work?
They help with comfort and perceived effort by moving air across the skin, and increasing air movement is one of the controls Safe Work Australia recognises. They are not a substitute for water, rest, shade or rescheduling heavy work, and they are not air conditioning.
What is WBGT?
Wet Bulb Globe Temperature is a heat stress index used in occupational health and in ISO 7243. It combines air temperature, humidity, radiant heat and air movement to reflect how hot conditions actually feel to a working body, rather than relying on air temperature alone.
How we work out the estimate
The estimate multiplies four figures: workers × hot days × productivity lost on a hot day × cost per worker per day. The result is shown as a range of roughly plus or minus 30 percent.
Productivity loss on a hot day is drawn from heat exposure-response research. Output holds steady until heat passes a threshold near 25 to 27 degrees WBGT, then falls as workers slow and rest more. We map work intensity and climate to a loss figure within the ranges those studies report.
As a national benchmark, Zander and colleagues estimated heat cost about US$655 per worker each year, scaling to roughly US$6.2 billion across the workforce. Our per-worker figures for heat-exposed crews sit above that average, because the national figure includes many workers with little heat exposure.
Sources:
- Zander et al. (2015), Heat stress causes substantial labour productivity loss in Australia, Nature Climate Change.
- Kjellstrom et al. (2018), exposure-response functions for workplace heat and labour productivity.
- Safe Work Australia, Managing the risks of working in heat, and workers compensation claims data.