Blocking an unused chimney will reduce the movement of air and improve the comfort of your home.
Chimneys used with open fireplaces are designed to extract air from the house, whether or not a fire is burning. This means that your chimney can let a lot of air in and out of your home. Blocking the chimney when it isn’t being used will reduce the movement of air up and down your chimney and improve the comfort of your home.
Dampers can be closed when you are not using your fireplace, to prevent air from moving in and out of your home.
Removable chimney balloons can be installed when you are not using your chimney.
Installation of a removable screen is another option, but this will require some carpentry work.
Special care needs to be taken in houses with certain types of internal gas appliances, as they require fixed ventilation to expel the products of combustion from the home and operate safely.
Does your chimney already have a damper installed? This may seem like an obvious question, but dampers are installed out of sight so you may not be aware that it’s there. Look for a chain sitting just up inside the chimney or a lever/handle. Some dampers sit on top of the chimney and others are located in the 'throat' of the chimney. But if you can feel a draught coming down your chimney, chances are you don't have a damper.
If you don't have a chimney damper you can either:
The chimney balloon should sit in the throat of the chimney and effectively seal off the flow of air. The shape and size of the balloon must be suitable for your specific chimney and needs to be installed correctly to achieve a good seal. Carefully follow the installation instructions provided with the chimney balloon.
Install insulation in your ceiling, walls and floors to create a sealed envelope which acts like a thermos in winter and an esky in summer.