The flue that lets outside air into the firebox and lets the exhaust gas out is always open. When you don't have a fire the cold outside air is coming into the firebox and you have radiant cold! If you are not using your fireplace or don't use it often you may want to use our Flue-zee Flue Cover inside the firebox. You need to open the glass front and place the cover over the flue opening. Typically, our 8" Flue-zee works here. See position of #1 on diagram - flue openings inside the in firebox.
The Convective Heat vent that you see circulates warm air when you have a fire. When you have no fire the cold air in this vent begins to circulate in the opposite direction and throws cold air out of the bottom of the vent. Blocking this cold air at the bottom vent and the top vent with our Magnetic Fireplace Vent Covers will stop this cold air. Our cover will slide up under a small upper awning if you choose to cover the top vent. Stopping this cold convection will give you a lot of relief. You must remove the covers when you have a fire to get warm air circulating. If your vents protrude (looking more like venetian blinds) and are not flat to hold the magnets flat around the edge, or if you have a screen over them, our magnetic covers will not work. See position #2 in diagram of vent openings to Convection Air Intake/Convection Heat.
Our Termination Cap Covers were created for fireplaces with uneven vents that cannot use our Magnetic Vent Covers and choose not to cover the flue inside the firebox. They will stop the cold outside air from entering the firebox but will not stop the Convection Draft caused by interior air. The colder the firebox, the colder the convection draft and the radiant draft. If you are using our flue cover inside the firebox you would not need the outside termination cap cover. See position #3 for Exhaust Gas Termination Cap.