Indoor Heating and Poor Ventilation in Winter: Hidden Health Risks You Should Know

With winter, indoor heating becomes essential for comfort. But according to Dr Jai Mullerpattan, consultant pulmonologist, P.D Hinduja Hospital and Medical Research Centre, poorly ventilated homes combined with indoor heating can significantly increase indoor air pollution, leading to serious health risks. “This creates hazardous, stagnant air, leading to serious health risks, including carbon dioxide poisoning, severe respiratory issues from mould/damp, headaches, and increased virus transmission,” he said. While many modern homes are tightly sealed to conserve warmth, the process may improve energy efficiency, but it also traps pollutants indoors. Without proper airflow, harmful gases and allergens accumulate, creating stagnant, hazardous air.

Why does indoor heating become dangerous without ventilation?

Homes using unvented gas heaters, wood stoves, fireplaces, or kerosene heaters are particularly vulnerable. According to Dr Mullerpattan, inadequate ventilation prevents the safe release of combustion by-products such as carbon monoxide (CO) and excess carbon dioxide. Carbon monoxide is especially dangerous because it is colourless and odourless, making it difficult to detect. Even low-level exposure can cause headaches, dizziness, nausea, confusion, and in severe cases, fatal poisoning.

Key health risks for poor ventilation

Dr Mullerpattan highlights several major risks linked to indoor heating and poor airflow, which include:

Respiratory issues

Poor ventilation increases exposure to dust, volatile organic compounds (VOCs), mould spores, and allergens. Damp walls and closed spaces encourage mould growth, triggering asthma, bronchitis, allergic rhinitis, and chronic cough.

Carbon monoxide poisoning

Faulty or poorly ventilated heating systems can leak CO gas, which reduces oxygen supply to vital organs. Symptoms include weakness, chest pain, blurred vision, and loss of consciousness.

Sick building syndrome

Many people experience persistent symptoms indoors, including headaches, throat irritation, eye discomfort, nausea, and fatigue — often relieved when they step outside. This condition is commonly referred to as sick building syndrome.

Increased infection risk

Stagnant indoor air allows viruses and bacteria to circulate longer. During winter, poor ventilation increases the spread of influenza, COVID-19, and other respiratory infections, especially in crowded homes.

Reduced mental performance

High carbon dioxide levels can lead to drowsiness, poor concentration, and mental fatigue. Studies show that inadequate airflow affects cognitive performance and productivity.

Long-term health effects

Chronic exposure to indoor air pollutants may raise the risk of cardiovascular disease, chronic lung disease, and even certain cancers.Also read: FDA Refuses to Review Moderna’s mRNA Flu Vaccine Application

Easy ways to protect your health

A few simple steps that Dr Mullerpattan has listed can dramatically improve indoor air quality, including:

• Open windows daily for cross-ventilation
• Use extractor fans in kitchens and bathrooms
• Install carbon monoxide detectors
• Service heaters and chimneys regularly
• Avoid unvented heating devices

Consider installing Mechanical Heat Recovery Ventilation (MHRV) systems, which replace stale air with filtered fresh air while preserving indoor warmth