Paul, Ernie and Erica continue their conversation on the Rocket Mass Heaters workshop that started in part 1. They first talk about an idea that was brought up during the workshop to put the exhaust in a greenhouse to help with plant growth. The concept is that since the exhaust from a Rocket Mass Heater is only oxygen and carbon dioxide, the latter should help with photosynthesis. However, the exhaust from a Rocket Mass Heater is not always clean, especially at the beginning of the burn when the heat riser is still cold. The exhaust at that time can be smoky, contain pollutants and the extremely dangerous carbon monoxide. In short, the exhaust can kill people and plants.
Ernie points out that such a system would be risky every time and that it would just be a matter of time before someone forgets a step and causes harm. They all agree that fermentation is a much safer way to add carbon dioxide to the greenhouse atmosphere. They then talk about the issue of having a completely closed system at small scales.
The next subject that they cover in the podcast is the timberframed outhouse that Caleb built for the workshop. They point out that it used Paul's wheely bin idea. Erica then talks about the different composting toilets they saw on their tour. She expresses how uncomfortable the bucket composting toilets make her because of the risk of reusing the buckets by mistake.
They talk about the risk associated with handling poop and different safe composting toilet designs. They conclude the podcast by all agreeing that it is better to design systems that work for people as they currently are instead of people changing to work the system.