What most people seem to do in this situation is install a chimney plug or balloon.
Plug unused chimney.
Sealing your older unused chimney should not be a complicated task as long as attention is paid to prevention of air intrusion as well as environmental and pest control.
How to close an unused chimney.
Fireplace chimney draftstopper plug round fits most metal zero clearance fireplaces.
Should unused chimneys be capped if your no longer going to use them for a real fire again.
The insul plug is constructed of a ceramic based fireproof insulating material.
It provides a thermal break from combustibles and prevents downdrafts from entering the room.
In short yes there are many factors to why you should cap off a unused chimney but it has to be done properly and just not blocked off at the top of the stack.
Made of polyurethane it fits into most fireplaces that have a rectangular shaped damper.
The fireplace flue can be a major source of energy loss.
Cutting energy expenses is easy when you add weather stripping to your fireplace damper with the battic door energy conservation products 18 in.
You can also seal the edges with foam weatherstripping tape too.
Cooled or heated air from inside your home can escape through the chimney causing your hvac system to work.
The balloon is inserted into your chimney and then you blow it up until it fits snugly in the space thereby blocking the air flow.
When it s time to use the chimney again all you have to do is deflate the plug and pull it out.
The black outside plate covers up to a 10 diameter hole.
The insul plug blocks old unused thimble holes in masonry chimneys.