Ember protection versus R-rated hearth... stove performance differences

[Light in the Dark]

A new one for you all the chew on...

So are there inherent performance differences between stoves that require ember only protection, versus those which need R-rated hearths? I assume that the ember only protection are somehow inherently less performers versus the others (from a room heating standpoint).... but I dont know.

Thoughts?

 

[firefighterjake]

I'm thinking it may have more to do with how the heat is reflected and directed with its construction and not reflective of how well it works as a space heater.

 

[mepellet]

My Harman P61A required a thermal protection board, not just ember protection. Dealer didn't know about it until I told them that they sold me the wrong board. Learned about it on the pellet mill board. Another member pulled his stove and board up to find his vinyl floor discolored from the heat. The stoves physical characteristics has more to do with this requirement than anything else.

 

[dorkweed]

My Englander 13NC requires a hearth pad of an R factor or 2. I met that plus a bit.

That said my hearth only gets "warm" in front of the stove, just down in front of the glass on the door The sides, back, and bottom of the stove don't even get "warm" at all IMHO

 

[begreen]

A new one for you all the chew on...

So are there inherent performance differences between stoves that require ember only protection, versus those which need R-rated hearths? I assume that the ember only protection are somehow inherently less performers versus the others (from a room heating standpoint).... but I dont know.

Thoughts?

The numbers are not related to performance. Hearth protection requirements are related to how well the firebox is insulated from the hearth and how the stove projects heat ahead of it. An ashlip can make a large difference here as do a taller pedestal or legs.

 

[Slow1]

The numbers are not related to performance. Hearth protection requirements are related to how well the firebox is insulated from the hearth and how the stove projects heat ahead of it. An ashlip can make a large difference here.

As a case in point - when the folks at Woodstock were finalizing the PH they initially were looking at having to require a hearth pad with greater R-value. Clearly given the number of folks who potentially would want to upgrade from a FV as well as the general simplicity of building a pad with just sheetrock and tile, they had a distinct interest in getting the requirement down to this. Now the PH is very well shielded/insulated on the bottom of the stove but the hotspot from what I understood was out in front where heat was radiating on the floor. In the end the solution was the "optional" ash lip (for those who didn't want to meet the higher R-Value requirement in a pad) as well as I believe the changed the glass on the stove to be IR reflective to keep a bit more in the stove (not positive that this was the driving factor on that decision or not though). Anyway - the ash lip is clearly not going to do anything with ashes as it is a side load stove, but it makes for about a 4" heat shield sticking out the front of the box that reflects some heat that I have to assume then keeps that critical hot spot in front of the stove from being high enough to require additional insulation.

At any rate - I've not sensed any relationship between the hearth requirements and stove performance one way or the other. My first stove had a greater requirement than ember protection and it was the worst performing stove I had - nothing to do with the hearthpad though.

 

[Light in the Dark]

I guess what I mean, and it was touched upon... obviously the heat does not travel downward in 'ember' stoves... but does that mean that it simply radiates out elsewhere... or what exactly? Looking at the Carrabassett got me thinking, since it lacks an ash pan, and only requires ember protection (firebricks line the bottom of the stove)

 

[Slow1]

My impression is that most EPA stoves (cat and non-cat) throw the majority of their heat off the top and the to some degree out the glass front. The sides are secondary and the back is often very well shielded (reduce clearance) as well may be the bottom. Keeping heat in the firebox keeps the burns clean so insulating more sides is a good thing.

At any rate - I think you are correct in that it simply radiates out elsewhere. Top and front would be my guess as the main areas. Then of course there are stoves with a convection jacket and I'm not sure if they may actually draw more heat from the back and blow the air around the stove so they could be different - but again, I think even these are largely pulling off the top too.