There is no single legal temperature for every UK workplace, but indoor workplaces must be kept at a reasonable temperature during working hours. HSE guidance says workrooms should normally be at least 16°C, or at least 13°C where much of the work involves rigorous physical effort. Those figures are guidance, not automatic pass-or-fail limits.
What is reasonable depends on the work, the building and the people doing the job. An office at 16°C may still feel uncomfortably cold to sedentary staff, while a physically demanding workplace may need a lower air temperature. Employers must assess the risk, consult workers and take appropriate action.
The short answer for offices and indoor work
For a mainly sedentary indoor workplace such as an office, the HSE Approved Code of Practice suggests a normal minimum of 16°C. If the work involves rigorous physical effort, it suggests 13°C. GOV.UK gives the same guidance and makes clear that there is no statutory minimum or maximum temperature number.
The legal requirement is that the temperature is reasonable. A thermometer reading is useful evidence, but it does not settle every case. Employers must consider health and safety risks and put controls in place.
Why 16°C is not a universal target
Sixteen degrees is a normal minimum in the guidance, not a recommended comfort target for every office. People who sit still can feel cold at that temperature, especially near draughty doors, windows or external walls. A call centre, workshop, kitchen, warehouse and care setting can all need different controls.
HSE says air temperature alone is not an accurate measure of thermal comfort. It identifies six basic factors: air temperature, radiant temperature, air movement, humidity, clothing or personal protective equipment, and work rate. The needs and characteristics of workers also matter.
What temperature is comfortable in an office?
There is no official number that will satisfy everyone. Many offices are comfortable somewhere around the high teens to low twenties, but the correct approach is to assess the actual workplace rather than declare one preferred setting.
Ask whether people can work comfortably without special clothing, whether cold or heat is affecting concentration, and whether conditions vary across the room. HSE advises asking workers or their representatives as a simple first step when estimating thermal comfort.
What employers must consider
HSE says employers must assess workplace temperature risks and put controls in place. They should consult workers or representatives about suitable ways to manage heat or cold. A risk assessment should reflect the people present, including anyone whose health, disability, pregnancy, age, medication or PPE may make temperature more significant.
The Workplace Regulations also require a sufficient number of thermometers so workers can determine the temperature in indoor workplaces. Measurements should be meaningful: take them close to workstations, at working height and away from direct sunlight or a local heat source.
How to measure a workplace temperature properly
- Use a suitable thermometer rather than relying only on a wall thermostat display.
- Measure at the height and location where people work.
- Avoid windows, radiators, direct sun, exterior doors and equipment that distort the reading.
- Record the time, location and outside conditions.
- Repeat readings in warmer and colder parts of the day.
- Record employee reports alongside the numbers.
A single reading beside the boiler controls may not represent a draughty desk or a hot production area. If complaints are concentrated in one zone, compare that zone with the thermostat location and the rest of the building.
Why the thermostat reading may not match how work feels
Radiant heat from sunlight, machinery or a large cold window can change comfort without changing the room thermometer much. Air movement can cool people in a warm room or create an uncomfortable draught in a cool one. High humidity reduces the body’s ability to lose heat through evaporating sweat.
Work rate matters because physical activity creates heat. Clothing and PPE can trap it. A uniform policy can also prevent workers from adding or removing layers. These are reasons to treat temperature as a risk-management question, not just a dispute over one thermostat number.
If the workplace is too cold
Employers should first identify the cause. Is the heating switched off too early, programmed for the wrong days or trying to warm an empty building schedule? Are radiators cold, the boiler showing a fault, doors left open or workstations in a draught?
Practical controls may include repairing the heating, adjusting operating times, reducing draughts, relocating work, providing local heat where it can be used safely, allowing suitable layers and giving warm rest areas or breaks. Temporary electrical heaters must be appropriate, positioned safely and included in the workplace’s electrical and fire-safety arrangements.
If the workplace is too hot
There is no legal maximum workplace temperature. That does not remove the employer’s duty to control risk. HSE describes heat as a hazard that must be managed like other hazards.
Controls can include reducing radiant heat, shading windows, increasing suitable ventilation, changing work patterns, providing drinking water, allowing breaks and reviewing clothing or PPE where safe. Fans do not solve every problem, particularly where air is already very hot or a process creates contaminants.
When the heating system may be at fault
- the programmed heating period is correct but the boiler does not start;
- the thermostat calls for heat but radiators remain cold;
- only part of the workplace heats properly;
- the boiler loses pressure or shows a fault code;
- heating stops before the occupied area reaches its target;
- the controls disconnect, go blank or reset; or
- there are leaks, unusual noises or a carbon-monoxide alarm.
Record the exact boiler make and model, displayed code, pressure when cold, thermostat setting, measured room temperatures and affected zones. This gives an engineer useful evidence without anyone opening the appliance.
What workers can do
HSE advises workers to report temperature problems to their manager, union or workplace representative. Explain where and when the problem occurs, how it affects the work and whether temporary steps are helping. Add or remove layers where permitted, move away from direct heat where possible and take agreed breaks to warm up or cool down.
Do not bring an unapproved heater into work, obstruct ventilation, cover a thermostat or interfere with the boiler. These actions can create electrical, fire or control problems and may make the underlying fault harder to diagnose.
Home working
Someone working from home still needs a comfortable environment, but the heating controls are domestic. A desk beside a cold window may feel much colder than the thermostat location. Move the desk if practical, reduce safe draughts, use layers and heat the occupied room rather than chasing a high whole-house setting.
If the boiler cannot maintain a normal room temperature, check accessible user controls and the exact manual. Do not remove the casing or attempt an internal repair. Arrange a Gas Safe registered engineer for gas-appliance work.
Landlords, managing agents and shared premises
Responsibility for arranging a repair can depend on the lease and who controls the plant, but the employer still needs to manage the effect on workers. Report faults immediately to the building manager or landlord while putting suitable temporary controls in place. Do not let uncertainty about the repair contract delay a health-and-safety response.
Gas and carbon-monoxide safety
If anyone smells gas, suspects fumes or a carbon-monoxide alarm sounds, leave the affected area and follow emergency guidance. Do not keep operating a boiler to maintain the workplace temperature. Gas Safe Register advises against DIY gas-appliance repair; use a suitably qualified Gas Safe registered engineer.
Frequently asked questions
Is 16°C the legal minimum at work?
No fixed statutory minimum applies to every workplace. The law requires a reasonable indoor temperature, while the Approved Code of Practice says workrooms should normally be at least 16°C.
When does the 13°C figure apply?
It is the normal minimum suggested where much of the work involves rigorous physical effort. It is not a blanket target for every workshop or warehouse.
Is there a legal maximum temperature?
No. Employers must still assess heat as a hazard and control risks to health and safety.
Can staff refuse to work because it is cold?
A thermometer reading alone does not answer that question. Workers should report concerns promptly, while employers assess the risk, consult staff and take appropriate action. Seek union or specialist advice for a specific dispute.
Where should the workplace temperature be measured?
Measure near the workstation, at working height and away from windows or local heat sources. Use several locations if conditions vary across the workplace.
What if the boiler is running but the office stays cold?
Check the schedule, thermostat location and which radiators heat. Heat loss, circulation, radiator, control or boiler faults may be involved. Record the pattern and arrange a professional assessment.
Related boiler-help guides
- Why is my workplace cold when the heating is on?
- Workplace boiler not working: what to check
- Why is my thermostat not turning the heating on?
- Why are radiators not heating up evenly?
Workplace still cold because the boiler is not responding?
Book a fixed-price Incredaboil repair for an eligible Baxi, Worcester Bosch or Ideal boiler and get the heating fault assessed.