Introduction
Cold weather pushes many workplaces into quick fixes: plugging in fan heaters under desks, wheeling radiant heaters into stores, or using gas heaters in poorly ventilated areas. These “temporary” solutions often become permanent habits and that’s where the risk sits.
The Health and Safety Executive (HSE) expect employers to maintain a reasonable indoor temperature during working hours and to manage thermal comfort so people can work safely and effectively. In indoor workrooms, HSE guidance normally expects at least 16°C, or 13°C where the work involves rigorous physical effort.
Case Study
In February 2020, staff and pupils at a primary school reported symptoms including headaches and nausea. Several pupils were sent home, and staff needed medication to manage symptoms. The following day, gas testing identified high levels of carbon monoxide (CO) in parts of the school, and the building was evacuated.
An investigation by the HSE, alongside Gas Safe Register investigators, found that one of two auxiliary gas boilers were leaking carbon monoxide into the boiler room and school areas. The root cause was lack of maintenance. Following the investigation, the HSE stated that if faults had been found through required routine maintenance, the boiler would have been classed as “immediately dangerous” and disconnected until repaired.
Winter heating incidents are not limited to portable plug-in units. Fixed heating plant (boilers, space heaters, cabinet heaters) becomes higher consequence during winter because use increases, Ventilation can be reduced, and failures become more dangerous.
Key hazards
Fire and Ignition
- Heaters cited too close to paper, packaging, curtains, chemicals, aerosols, waste, or racking dust.
- Drying PPE/ clothing on heaters.
- Blocked vents causing overheating.
Burns and contact injury
- Hot surfaces on radiant/bar heaters and fan heater outlets
- Unprotected placement in walkways or near seated workers.
Electrical hazards (Portable electric especially)
- Damaged plugs, cables, loose connections, counterfeit units.
- Overloaded sockets, daisy-chained extensions, overheating adaptors.
- Poor maintenance increasing risk of shock and fire (electricity kills silently).
Carbon monoxide and indoor air quality (combustion heaters/ boilers)
- Inadequate servicing, flue failures, poor ventilation.
- CO exposure presenting as “winter illness” symptoms (headache, nausea, fatigue).
- Increased risk in enclosed rooms and temporary cabins.
Trips and slips
Trailing cables across floors, especially near entrances and drying areas.
Operational rift and unmanaged change
- “Personal heaters” introduced without approval, inspection, or fire risk review.
- Layout changes reducing heater clearance distances.
Legal Duties
Workplace (Health, Safety and Welfare) Regulations 1992, Regulation 7: Indoor workplace temperature must be “reasonable”.
Health and Safety at Work etc. Act 1974: General duty to protect employees and others from risks arising from work activities (covers heating arrangements).
Management of Health and Safety at Work Regulations 1999: Suitable and sufficient risk assessment and implementation of preventive/protective measures.
Electricity at Work Regulations 1989: Electrical systems and equipment must be constructed and maintained to prevent danger (covers portable heaters and supplies).
Gas Safety (Installation and Use) Regulations 1998: Safe installation, maintenance, and checks for gas appliances; failures can lead directly to prosecution.
Regulatory Reform (Fire Safety) Order 2005 (England & Wales): Duty to manage fire risk, including ignition sources such as heaters.
Control measures
- Stop ad-hoc heater buying. Issue one approved heater specification (or none) and remove non-approved units.
- Prioritise fixed heating and building maintenance over plug-in “workarounds”.
Placement and Separation
- Maintain safe clearance from combustibles; keep heaters off escape routes and away from storage stacks.
- Use stable positioning; prevent tip-over risk and keep outlets unobstructed.
Electrical Controls
- Apply a maintenance regime for portable equipment using user checks+ formal visual inspections+ testing where needed, aligned to HSE guidance on maintaining portable electrical equipment.
- Do not rely on the myth of automatic annual PAT for everything; the legal requirement is maintenance to prevent danger, with frequency based on risk.
- Avoid multi-way adaptors and extension chains; use correctly rated sockets and RCD protection where appropriate.
Combustion and gas controls
- Gas appliances and gas work must be handled by competent people (Gas Safe registered when required) and maintain properly.
- Ensure adequate ventilation, intact flues, and servicing aligned to manufacturer instructions and risk.
Fire safety controls
- Update the fire risk assessment when heaters are introduced or usage increases, and control ignition sources accordingly.
- Keep extinguishers accessible, enforce housekeeping, and maintain clear escape routes.
Management controls
- Create a short “Winter Heater Rules” standard:
- No personal heaters without approval
- Inspection before use
- No drying clothes on heaters
- Switch off when unattended
- Defects reported immediately
- Include detail about knowing inspection and maintenance requirements for any heating equipment or appliances they have and the importance of keeping records of inspection and maintenance
SUMMARY
Winter heaters are not a “comfort issue”. They are a controlled risk source: fire, burns, electrical failure, CO exposure, and poor decision-making under cold pressure. A compliant workplace approach is simple: maintain reasonable temperatures, control heater types and locations, maintain equipment based on risk, update the fire risk assessment, and treat gas and electrical heating as high-consequence systems not seasonal accessories.
