Purchase a top quality chimney draft stopper
First of all, you have to buy a decent and quality chimney draft stopper like the well known urethane pillow. This is a good choice as it is very simply to assemble. Moreover, select an item that matches the exact size of your fireplace or otherwise it would not be that effective, and will not work properly. Take measurements of your fireplace before you go to get the draft stopper so that you buy the correct size. If you do not do this, then you would be wasting your time and money.
Check the fireplace chimney
After that, you should inspect the fireplace chimney carefully with the help of a flashlight. When looking, check for any sharp metal or screws coming out of the damper. Moreover, also look for any gathered rubble and soot. Then clear the path from blockings with a brush or long stick or scrape off the dirt and soot. If you encounter a problem with the chimney damper, call a technician for a suitable replacement or general service and repair.
Assemble the urethane pillow
Furthermore, you will have to muster the popular urethane pillow. This you can do by following the directions on the box. Fill it with air with the help of an air pump and it will form a shape. Then make use of support handle of the draft to plug it smoothly below the damper. Fill the draft with the air pump and let it seal off the airway near the opening of the fireplace. After that, deflate the pillow draft by opening the valve before using it. Disjoint the draft with the handle and put it somewhere secure so that you can take it out again if you need it in the future.