[nick26]

On either side of my firebox in my fireplace, I have these metal doors that go out to vents on the outside. They are horribly drafty and pretty much falling out. I want to know why they originally put them in and if it's OK if I seal them up with brick and mortar? I have never seen them on any other fireplace ever. In case it's applicable I have 2 full flues in this chimney, one on the first floor and one in the walk out basement.
Thanks!

 

[BigJim]

They are for outside air for the fireplace. If they are not there you will pull air from inside your house and out the chimney your inside air will go and you fireplace will be less efficient. Isn't there a flap on the doors inside or outside?

 

[stadry]

do they feed directly into the firebox ?

 

[Tscarborough]

In some jurisdictions they are required, so check before you seal them up. You should just buy new covers, they will be a little more airtight.

 

[nick26]

do they feed directly into the firebox ?

Yes you can see where they are positioned here

 

[nick26]

They are for outside air for the fireplace. If they are not there you will pull air from inside your house and out the chimney your inside air will go and you fireplace will be less efficient. Isn't there a flap on the doors inside or outside?

That's what I suspected they were for, and I've tried opening and closing them while the fire was going to see if I felt a difference, but I still think they pretty much let cold air into the room even when the fire is going. They certainly counteract an efficiency gain I might get from having them when fire is going to when it's not because of how much air they let in.

They flap is only on the inside, the steel doors you see. On the outside is just a mesh grate.

 

[nick26]

In some jurisdictions they are required, so check before you seal them up. You should just buy new covers, they will be a little more airtight.

Do they make covers that have seals on them or something? I don't see how the metal on metal could seal well regardless of the crappy mortar job around them. I will look into the jurisdiction thing, but my neighbor's fireplace does have them, nor does any other I've seen in this town so I doubt that is an issue.

 

[stadry]

take the *&%@$%**!#! things out & fill the holes w/firebrick inside & stone outside,,, they're for providing fresh air for combustion rather than pulling air from inside the house which will eventually cause negative air pressure in your very fine home & cause cold air to infiltrate defeating your furnace's work,,, they would be more effective IF you had glass doors that sealed the opening well but its also more $$$,,, fwiw, we rarely have a fire in ours due to the same issue - heat the air inside our home then exhaust it out the chimney :furious:

 

[Tscarborough]

If you do not have them, you are warming the air and exhausting it out the chimney, with the outside air kits you do not do so (glass doors do help through). The amount of air leaking around those vents in good condition is about 1/100 of what you lose through one regular window.