Understanding the Hidden Health Risks of Home Heating

Wood-burning stoves and open fires have become increasingly popular over recent decades. While they may create a cosy atmosphere, the by-products of combustion can cause serious harm to our health — especially for those suffering from asthma, respiratory infections, or general sensitivity to polluted air.

From wood to kerosene, gas to bioethanol, every fuel type carries risks. By understanding these risks, you can make informed choices about the way you heat your home.

Why Indoor Air Quality Matters

Whenever you burn fuel of any kind, the process produces pollutants. These include fine particles (PM2.5), volatile organic compounds (VOCs), nitrogen oxides, carbon monoxide, and even heavy metals. Poor ventilation, faulty appliances, defective chimneys and flue systems, or outdated and/or poor installations can significantly increase exposure.

Homes with wood-burning stoves often have three times the level of indoor pollution compared to those without.

Heating Fuels and Their Health Impacts

Wood-Burning Stoves & Open Fires

Wood smoke contains:

PM2.5 particles (dangerous to heart and lungs)
Benzene & formaldehyde (carcinogens)
PAHs (linked to cancer and immunity suppression)
Carbon monoxide
Dioxins
Heavy metals (lead, cadmium, mercury, arsenic)
Wood burning can:

Trigger asthma attacks.
Increase risk of heart disease.
Worsen COPD
Increase susceptibility to respiratory infections.
Raise cancer risk.
Even modern “eco-design” stoves release pollutants during lighting, operation, refuelling, and door opening.

Kerosene (Oil Boilers)

Kerosene combustion can release:

Carbon monoxide
PM2.5
Nitrogen dioxide (NO2)
Sulphur dioxide (SO2)
Formaldehyde
Carcinogenic PAHs
The WHO recommends avoiding kerosene for domestic use due to its toxicity.

LPG (Liquid Petroleum Gas)

LPG is cleaner than wood but still contains:

Propane
Butane
Pentane
Propylene
These can cause dizziness, respiratory irritation and skin dryness, especially with poor ventilation.

Kerosene (Oil Boilers)

Kerosene combustion can release:

Carbon monoxide
PM2.5
Nitrogen dioxide (NO2)
Sulphur dioxide (SO2)
Formaldehyde
Carcinogenic PAHs
The WHO recommends avoiding kerosene for domestic use due to its toxicity.

LPG (Liquid Petroleum Gas)

LPG is cleaner than wood but still contains:

Propane
Butane
Pentane
Propylene
These can cause dizziness, respiratory irritation and skin dryness, especially with poor ventilation.

Natural Gas

Safer than wood or kerosene, but risks include:

Carbon monoxide leaks
Fire/explosion risk.
Nitrogen oxide emissions (can worsen asthma)
High-efficiency balanced-flue and glass-fronted gas fires significantly reduce exposure.

Bioethanol

Stylish and chimney-free, but:

Extremely flammable
Vapours can irritate the respiratory system.
Impurities (e.g., methanol, acetic acid) may pose health risks.
Accidents commonly occur during refuelling.
Electric Heating

The safest option for air quality.
No combustion, no fumes, and minimal health risks when used responsibly.

Safer Heating Choices

Lowest Risk:
Electric heating
Balanced-flue, room-sealed gas appliances
High-efficiency modern gas fires


Higher Risk:
LPG heaters
Bioethanol burners
Kerosene heaters
Wood-burning stoves & open fires (highest risk)

How to Reduce Indoor Pollution

Keep stoves regularly maintained.
Ensure chimneys/flues are professionally inspected & assessed by a registered and insured technician.
Never burn wood with a moisture content higher than 20%
Store wood in a perfectly dry and ventilated area
Avoid open fires entirely where possible.
Improve room ventilation if operating any combustion appliance
Upgrade insulation before adding the extra cost of standalone space heating.
Keep stove doors closed during operation.
Invest in a calibrated infra-red thermometer to confirm safe operational temperature parameters

Final Thoughts

Understanding the effects of combustion on indoor air quality can help you protect your health and make informed heating choices - especially if anyone in your home suffers from asthma or respiratory illness.