In the UK there is no law laid down that specifies a minimum, or indeed maximum temperature in the workplace.
Legislation does exist in the form of the Workplace (Health, Safety and Welfare) Regulations 1992 that does lay down the requirements of the workplace and in respect of the temperature of indoor workplaces states;
‘During working hours, the temperature in all workplaces inside buildings shall be reasonable.’
As with all such tests of “reasonableness” the circumstances of what type or workplace environment exists and what duties are required of staff and whether any special clothing or PPE is provided will be an important factor.
In practice it is recommenced that the minimum temperature for indoor workplaces should be 16°C or 13°C where the work involves a significant amount of physical effort and work.
Whilst these temperatures are guidelines only, the failure of an employer to meet these temperature standards might certainly be persuasive in any actions brought under the Workplace (Health, Safety and Welfare) Regulations 1992.
For many employees it is not the cold that is the main concern at work. Many employees are working in environments where the temperature is necessarily higher than normal. In these circumstances it is the duty of the employer to undertake a risk assessment and take whatever steps to minimise employee exposure to heat stress