A properly sized gas log set isn't just one that will fit inside your fireplace. All gas log sets have their own specific clearance requirements, and trying to use a log set in a fireplace that doesn't meet its requirements can cause serious problems. Installing a log set that is too large, for example, may prevent your fireplace from drafting properly and could impede the efficiency of your burner. In some extreme cases, a lack of air flow might even cause your log set to become dangerously overheated and start to melt. On the other hand, if you install a log set that is too small, you'll probably find yourself unsatisfied with your hearth's appearance.
But don't worry; finding the right gas log set isn't as hard as it sounds. You can easily avoid all of those problems by taking a few simple measurements of your fireplace:
FRONT WIDTH — This refers to the width of the very front of your fireplace's opening. Make sure you take this measurement inside of your fireplace opening, not in front of it.
BACK WIDTH — This measurement should be taken at the back wall of your fireplace, as far back as you can go. Most fireplaces are tapered, so don't be concerned if your back width is smaller than your front width.
DEPTH — This describes how far back your fireplace goes. You can obtain this measurement by placing one end of your tape measure at the back wall of your fireplace and bringing the other forward until you reach the edge of the front opening.