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I found this out by accident.
You can double (or more) the heat from your fireplace by insulating the walls and using thicker firebrick.
Here's how I found out. I have a ~5 foot wide outdoor fireplace. I had it lined with 1/2 thick firebricks. The firebricks weren't enough to protect the CMU from the heat and the CMUs stated cracking.
To remedy the heat issue, I pulled out the splits, insulated with 1" KFAC-19, then put a layer of full size firebricks to line the fireplace.
I had the fireplace in operation for one year in the old configuration so I have a pretty good gauge of the heat output. With the new configuration, I can honestly say there is a minimum of 2X the amount of heat output.
Obviously I don't have any controlled tests of scientific before and after tests, but it is WAY hotter.
I am guessing it is a combination of the almost zero heat loss through the sides and back combined with the heat retention of the full size bricks.
Regardless, If you are building new, I would suggest spending a few extra bucks and insulating full bricks. The heat benefit and protection from potential problems down the road are way worth it.
Regards,
Chris
You can double (or more) the heat from your fireplace by insulating the walls and using thicker firebrick.
Here's how I found out. I have a ~5 foot wide outdoor fireplace. I had it lined with 1/2 thick firebricks. The firebricks weren't enough to protect the CMU from the heat and the CMUs stated cracking.
To remedy the heat issue, I pulled out the splits, insulated with 1" KFAC-19, then put a layer of full size firebricks to line the fireplace.
I had the fireplace in operation for one year in the old configuration so I have a pretty good gauge of the heat output. With the new configuration, I can honestly say there is a minimum of 2X the amount of heat output.
Obviously I don't have any controlled tests of scientific before and after tests, but it is WAY hotter.
I am guessing it is a combination of the almost zero heat loss through the sides and back combined with the heat retention of the full size bricks.
Regardless, If you are building new, I would suggest spending a few extra bucks and insulating full bricks. The heat benefit and protection from potential problems down the road are way worth it.
Regards,
Chris