Block off Plate -Dumb Question

[Jearley35purdue]

Gents, have a Napoleon 1402 insert In a mason fireplace, 27' liner through an exterior wall chimney. This stove has a box/shroud around the firebox that the dual fans route air through and back into the living area. I'm reading all this talk about block off plates and wondering with my particular set up if it will make a difference. I'm guessing all inserts are fabricated in the same manner as mine, when I say same meaning physical attributes, not design or materials. There is a cap at the top of the chimney, but I'm guessing that my stove is also trying to heat naturally the 27' of air and exterior brick above the shroud on the stove. Am I correct? If so, anyone with a 1402 fabricated a block off plate with success in noticing a difference in output..

 

[fitter9]

I have a different insert, but with a similar chimney. It made a huge difference after i installed my roxul insulation and block plate. A lot more heat radiates into the room. Also my burn times increased because the firebox doesn't cool as fast.

 

[RickBlaine]

You are correct- right now, your insert is heating the 27' of air and brick above- that is a lot of heat loss.

There are a few members here who bought a cheap Infra-Red gun at Menards or Harbor Freight, then went outside while a warm fire was raging inside. When aiming the red dot at the outside bricks- some of these guys were measuring 20-40 degree difference between the outside air temp and the outside brick temperature. Not good.

After a block-off plate, (and low-cost Roxul insulation) your IR gun won't measure a difference. That means your outside chimney (I have one) is NOT sending heat to the great outdoors.

Block-off plates are not complicated, nor is stuffing Roxul into the smoke shelf and laying Roxul on top of the block-off plate. I even added some directly underneath my chimney's top plate. Zero heat loss!

A block-off plate and Roxul is a great bang for the buck. I understand it can freak people out when you have the stove out and there is dust, tools, and such laying about, but ignore the screams and press on, good soldier. You will notice the improvement.

 

[Jearley35purdue]

You are correct- right now, your insert is heating the 27' of air and brick above- that is a lot of heat loss.

There are a few members here who bought a cheap Infra-Red gun at Menards or Harbor Freight, then went outside while a warm fire was raging inside. When aiming the red dot at the outside bricks- some of these guys were measuring 20-40 degree difference between the outside air temp and the outside brick temperature. Not good.

After a block-off plate, (and low-cost Roxul insulation) your IR gun won't measure a difference. That means your outside chimney (I have one) is NOT sending heat to the great outdoors.

Block-off plates are not complicated, nor is stuffing Roxul into the smoke shelf and laying Roxul on top of the block-off plate. I even added some directly underneath my chimney's top plate. Zero heat loss!

A block-off plate and Roxul is a great bang for the buck. I understand it can freak people out when you have the stove out and there is dust, tools, and such laying about, but ignore the screams and press on, good soldier. You will notice the improvement.

RickBlaine, Thanks a bunch for the confirmation. I just imagined getting a bunch more output into at least the direct room that the stove is installed than I'm getting now. On a chilly day 20-30, I can only get it to 71-72F in the room the stove is installed in which is only about 14'x27' with 9 ft ceilings. I should be getting cooked out of this room if I so choose with good wood and a hot stove. My house isn't that old, built in 96, could it be better sealed yes, but it surely isn't as drafty as some older homes with older windows. Not sure if I have the courage to yank the stove out and go at the block off alone. Fairly handy when it comes to construction and fabrication, but the thought of yanking out a brand new installed stove makes me nervous.