How to insulate an unused fireplace

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An unblocked chimney can produce cold draughts blowing through your house during the winter. This in turn can lead to higher energy bills as your central heating system tries to compensate for the heat loss from your open chimney.

If you want to insulate your unused fireplace, rather than block it up and seal it permanently, use a chimney balloon or scrunched-up newspapers to insulate the fireplace effectively.

Newspaper insulation

Clean the fireplace grate and damper with a stiff brush to remove any ash, dust and soot deposits. If you haven’t had the chimney swept for more than two years then hire a professional chimney sweep to clean it properly before you insulate the fireplace.

Scrunch up the pages from several old newspapers into tight balls. The balls will loosen shortly after you scrunch them up and this will help to keep them into position in the chimney just above the fireplace.

Push the scrunched-up newspaper balls into the chimney opening at the top of the fireplace. Continue to add newspaper balls until you have closed the gap at the top of the fireplace. Pack the newspaper firmly into place to form an effective barrier but don’t push them up the chimney by any more than an arm’s length or you might encounter problems when you try to remove them.

Drop a tissue paper or a feather across the fireplace opening. The item should fall straight to the ground if you have insulated the chimney properly. If the feather or tissue blows away from the fireplace then you might still have a draft. Solve this problem by adding more newspaper balls.

Chimney balloon Insulation

Clean the fireplace damper and grate thoroughly with a stiff brush to remove any ash, soot or dust from the area around and immediately above the fireplace.

Remove the chimney balloon from its packaging.

Move the tap at the bottom of the balloon to the “Open” position in line with the hand-grip and blow a little air into the balloon to partially inflate the device.

Push the chimney balloon into place above the fireplace opening and up the chimney by about 300 mm/1 foot.

Inflate the chimney balloon until it fits against the chimney securely and tightly and stays in place without support. Ensure that the white label at the bottom of the device is facing you as you inflate the balloon. Turn off the tap.

Check the balloon in two hours after the air inside has cooled. If the balloon has contracted due to the cooling air, open the tap and inflate it again. Write a “Remember” message on the supplied label and place this in the fireplace grate. This will remind you that you have a balloon inserted in your chimney when you want to use the fireplace again.