Safety, Health and Welfare at Work (General Application) Regulations 2007
7. (1) An employer shall ensure that—
(a) during working hours, the temperature in rooms containing workstations is appropriate for human beings, having regard to the working methods being used and the physical demands placed on the employees,
(b) for sedentary office work, a minimum temperature of 17.5°C, so far as is reasonably practicable, is achieved and maintained at every workstation after the first hour's work,
(c) for other sedentary work, at every workstation where a substantial proportion of the work is done sitting and does not involve serious physical effort, a minimum temperature of 16°C is, so far as is reasonably practicable, achieved and maintained after the first hour's work,
(d) means are available to enable persons at work to measure the temperature in any workplace inside a building,
(e) the temperature in rest areas, rooms for duty staff, sanitary facilities, canteens and first-aid rooms is appropriate to the particular purpose of such areas, and
(f) in relation to windows, skylights and glass partitions, excessive effects of sunlight are avoided in places of work, having regard to the nature of the work and the characteristics of the place of work.
(2) The temperature referred to in paragraphs (1)(b) and (c) shall be a dry bulb temperature taken at the working position of the employee at 1.1 m above the floor surface.
(3) Where, due to process requirements, a workplace temperature below 16°C is necessary the employer shall assess the risks and take any necessary measures to ensure the safety health and welfare of the employer's employees.