When you call us or go to FireplaceDoorsOnline.com looking for a door, one of the first questions we have for you is "Is your fireplace a Masonry or a Zero Clearance fireplace?". We'll walk you through the steps to figure out what type you have, because we know that your safety depends on getting the right type of door for your fireplace.
Zero Clearance fireplaces are pre-fabricated in a factory and come as a whole unit. They can be installed with little clearance to the combustible components of your home (walls, studs, mantel, etc). They have louvers above and below the fireplace that allow air to flow around the outside of the firebox, insulating it and preventing it from burning those combustible items nearby. The doors of a Zero Clearance fireplace need to have gaps in them, as well, to help with this cooling effect.
Masonry fireplace doors are not made with these gaps, and therefore must NEVER be installed on a ZC fireplace. Masonry doors fit on the outside of your fireplace and if forced onto a Zero Clearance fireplace, will cover some of the louvers. This is very dangerous. The fire could become so hot that it breaks the glass in the doors. It could also get too hot for the surroundings and cause major damage to your walls, scorching the studs, even starting a house fire.
Unfortunately, if you're buying from a big box retailer, they may not have knowledgeable staff on hand and will sell you a masonry door for your ZC fireplace. This can be seen on the Lowe's website. (Photo on the right) A reviewer was "very happy" with his door after he had to make a few modifications to it. The reason he had to make those modifications is because he had a ZC fireplace and he bought Masonry doors. When installing this door, he totally covered over the louvered section.
When you purchase a house, make sure to check your fireplace for issues like this. This is something a home inspector might not always catch. This photo (on the left) is from a new homeowner that was wanting to update the look of his fireplace with some new doors. He had recently bought the house and was doing some remodeling. When he sent us this image of his fireplace, we quickly told him to not use the fireplace at all until he could replace the doors. The previous homeowner had installed Masonry doors on their Zero Clearance fireplace. Some homeowners opt to go with a big box store like Home Depot or Lowe's because their prices on doors are cheaper, but end up buying the wrong item because of the employee's do not have the experience needed to know the differences in these fireplaces. We helped him find a Zero Clearance fireplace door that fit his decor needs, and would be much safer.