What do front width and rear width mean on a gas log sizing chart?
Front width and rear width are the two widths your firebox must have to accept a given log set, because fireboxes taper — wider at the opening, narrower at the back wall. The chart lists a minimum for each. The grate is wider up front and pinches in at the rear to match, so both numbers have to clear, not just the front.
Why a firebox has two widths
Almost every firebox is wider at the front opening than at the back wall — masons angle the side walls inward to throw heat out into the room. That taper is why a sizing chart gives you both a minimum front width and a minimum rear width. A log set's grate mirrors that shape: broad across the front where you see the logs, pinched in at the back where it meets the narrow rear wall.
The back number is the one that usually bites
We see this weekly on older Asheville and Weaverville masonry fireboxes — the front measures plenty wide, the customer assumes any set will fit, and then the rear wall is four or five inches tighter than expected. If the set's required rear width doesn't clear, the logs crowd the back wall, flames impinge on brick, and you get soot and poor flame shape. Both minimums have to be met, and the tighter rear dimension governs the fit more often than the front.
How to capture it
Measure the width at the very front of the opening, then again flat against the back wall, plus depth and height. Those two widths tell us — and the manufacturer's spec sheet — exactly which nominal size seats with clearance. Guessing off the front alone is the most common sizing mistake we correct. Bring both numbers to the showroom or call (828) 545-0525 and we'll confirm the set before we spec a thing.
Related questions
- My firebox is narrower at the back than the front — which width do I use?
- When a gas log set is called 24 inches, what does that measurement actually refer to?
- How do I measure my firebox for gas logs?
- Can gas logs be too big for my firebox?
- How much clearance do gas logs need from the firebox walls?
- How many BTUs per square foot do I need to heat a room with a fireplace?
Still deciding? Talk to a real installer.
Free assessments across Western North Carolina — no pressure, straight answers.