Rmh failed to heat the room according to this youtube video

What is the reason that it failed?Pea gravel?Did he insulate the bench from the walls and the floor?

Why did it fail ?   Well we won't know now. It was a beautiful job of building.
But it was a well made video with her honest opinion that it didn't work for them.

It seemed like the heater was working fine.
She said that it failed to heat the air in the house, both when the fire was lit and afterwards.
To me, it is most likely that the house has leaks for heat to get out and cold air to get in.
Perhaps her old stove pulls its air down the chimney?

I have seen a video some time ago where the guy was talking about cold air being drawn into the room to fuel the rocket heater.
He said it comes in through all the gaps, and his solution was to place a vent in the wall near where the fire would be.
I have seen another solution where an inlet pipe (for air) came down inside the chimney from outside, and into the fire chamber.

There is another version where an air intake has a flap valve to open once the stale room air has been burned, and you just want the new fresh air to be warmed.

In this video, Paul talks about an air vent.

I haven't had a chance to watch the video yet, but I have some initial thoughts just from the cover image.

Assuming the video is recent... she is wearing a T shirt indoors in winter. Clearly her expectations of comfort are at the high end of the indoor temperature range. My parents conventional wood stove maintains their house at about 18 degrees (large, drafty, old building). When they crank the stove right up they can bring it up to 22 degrees in the room with the stove.  I wouldn't anticipate a rocket stove being able to make the room hotter than that.

In the dialogue... the bench got too hot to sit on, but didn't store heat or release heat well.

Towards the end of the first video, when they are dismantling it, you can see that the mass of the bench is very thin over the ductways. Looks to be about 1" of mass. Seems plausible that they were getting hotspots on the upper surface making it uncomfortable to sit on, and most of the heat was escaping from the that upper surface so the overall bench mass wasn't reaching temperature.

I'm seconding the level of comfort issue and the possible draftiness of the home. Also, the burning butt is definitely the lack of cob between the exhaust and the cushions. For those with RMH in their homes, what temps are you having in your house?

My house is 750sq. feet, straw bale/cob with an 8" batch rocket. Burning once daily my bench temp is usually 90-105F. Ambient temp in the house is 66-69F throughout the day, and usually 61-62F
in the morning time right before it is burned.

I've been giving some information in the comments to those videos, and correcting some misinformation. There seem to be a few people who understand why that installation didn't work correctly, and more who think it proves RMHs don't really work as well as woodstoves. More helpful comments from other people would probably be helpful. The video poster commented that she didn't think she would hear from Wheaton Labs, as if her experience was disproof...

could it have been because it was sitting directly on a cement floor ? the floor became a heat sink as well as pipes to close to the surface ?