Unflued gas heaters

Last updated: 01 May 2004

Introduction

Heating your home can be essential in winter to provide warmth and comfort, especially for people living in colder climates. If you have an unflued gas heater, there is an indoor air pollution hazard associated with its use that can affect your health.

This factsheet provides information on how unflued gas heaters can affect your health, and on how to reduce the potential hazard associated with the use of these appliances.

What is an unflued gas heater?

Gas heaters produce heat through burning gas fuel. When gas fuel is burnt, air pollutants and water vapour are also produced.

A flued gas heater vents these air pollutants and water vapour outside the home through a chimney or flue, while an unflued gas heater releases them directly into the home.This means that an unflued gas heater has the potential to cause indoor air pollution in your home that may affect your health.

What air pollutants will I be exposed to?

You will be exposed to higher levels of air pollutants inside your home when using an unflued gas heater.The air pollutants produced by an unflued gas heater that can be harmful to your health include carbon monoxide (CO) and nitrogen dioxide (NO2).

The levels of air pollutants produced by an unflued gas heater can vary depending on:

• the type of heater used
• correct installation of the heater and gas supply
• correct use of the heater
• how often it is serviced.

In addition, the level of air pollutants in the room you are heating can vary depending on:

• the size of the room being heated
• the amount of fresh air coming into the room (ie ventilation)
• whether other unflued gas appliances are also in use in the room or the home (ie gas ovens and cooktops).

Water vapour is not regarded as an air pollutant, however, moisture build-up can occur in the room you are heating. This may lead to the growth of moulds and dust mites, which have the potential to affect your health.

Possible health effects of exposure to air pollutants

Health effects caused by exposure to air pollutants can occur immediately at the time of exposure or be delayed.The effects will also depend on the type and amount of pollutants to which you are exposed. Some people are more susceptible than others and can suffer health effects more easily than others.

Carbon Monoxide (CO) is difficult to detect in your home. It is invisible and has no smell or taste. It can cause toxic effects in humans by depriving the body of oxygen, and impairing thinking and reflexes. CO levels will rise in a home where an unflued gas heater is in use.

A poorly installed heater, or a heater in a room with a lack of fresh air, can cause excessive levels of CO, and can lead to CO poisoning. Many people can experience flu-like symptoms from moderate CO exposure, while at even lower levels of exposure susceptible people can also experience chest pain. Exposure to very high concentrations of CO can result in death.

People most susceptible to the health effects of CO include those with heart disease, infants, unborn babies and the elderly.

Nitrogen Dioxide (NO2) can be difficult to detect in your home. NO2 is an invisible and tasteless gas, however, it does have a strong odour. NO2 levels will rise in a room where an unflued gas heater is in use. Breathing in high levels of NO2 can cause irritation of the respiratory tract and shortness of breath.

People with asthma and other respiratory diseases are particularly susceptible to the effects of exposure to NO2. Children may suffer more often from cold symptoms or asthma attacks if exposed over a prolonged period of time.

How can I reduce my exposure to air pollutants?

There are a number of ways to avoid or reduce exposure to air pollutants from an unflued gas heater.

Avoiding exposure:

• If gas is your preferred heating fuel, purchase a flued heater.
• Electric heaters produce no indoor air pollutant.

Reducing exposure:

• Ensure that an unflued gas heater is the correct size for the area in your home you wish to heat. Get advice from a retailer to determine the type and size of heater you need. Using a heater that is the wrong size can produce more air pollutants and may not be an energy efficient choice.
• If choosing an unflued gas heater, ensure it has an electronic ignition. Some heaters also have safety systems that can shut the heater off when there is not enough fresh air.
• The gas supply system in the home should be installed by a qualified tradesperson. This will ensure that any building code requirements are correctly followed. Improperly installed appliances can lead to higher levels of air pollutants and may pose a fire hazard. Ventilation in the room you are heating is very important. Check that the room you are heating has air vents and that these are not blocked. If you do not have air vents you should keep a door or a window open to allow the movement of air in and out of the room. This reduces the potential build-up of pollutants in the room and will also assist in reducing any build-up of moisture levels in the room, and possibly prevent mould growth.
• When using a heater, ensure that you are aware of the instructions for the use of the appliance. Read and follow any warning labels. If equipped with a safety device, understand how it works and why it may shut off an appliance.
• Never use an unflued gas heater overnight in the room where you sleep.
• Regular inspection and maintenance of your heater can assist with proper functioning. Appliances in poor working order can release higher amounts of combustion pollutants into your home.
• When using a gas oven or gas cooktop, be aware that these also produce air pollutants and contribute to higher levels in your home. Use a range hood that exhausts these pollutants outdoors, or open a window.

Related links

• More about indoor air pollution  http://www.health.nsw.gov.au/publichealth/environment/air/indoor.asp
• Wood smoke from wood-fired home heaters fact sheet  http://www.health.nsw.gov.au/factsheets/environmental/wood_smoke_pub.html