Solo Stove’s smokeless fire pits have grown in popularity because they look good and burn efficiently to keep the smoke down. The secondary burn effect helps them produce lots of heat from firewood.

The only problem though is that the heat goes primarily straight up, rather than outward to warm people sitting around the fire. They’ve tried to remedy this thermodynamic problem with accessories like the Heat Deflector that pushes some heat outwards.

According to a recent patent filing, Solo Stove appears to be working on improving lateral heating with the fire pit itself rather than with an accessory. They mentioned on their last earnings call that they’d have five new innovations this year, and I’d speculate this could be one of them.

Radiant Opening

The way that Solo Stove’s fire pits are designed today is there’s an inner wall and an outer wall surrounding the fire pit with an air gap in the middle. To get the secondary burn through the holes in the top, cold air is drawn through the bottom of the fire pit through the air gap and heated as it makes its way to the holes in the top. Less energy is then required for combustion of the pre-heated air.

The idea they’re developing is for a radiant opening on the side of the fire pit. They have a bunch of different embodiments on possible ways to implement this, but the primary idea is a portion of the fire pit wouldn’t be double walled.

The air gap is great for insulating the fire from outside air and for heating air for secondary burn, but it also keeps the hot air in the fire pit from radiating outside. The radiant opening would expose the outside air to hotter temperatures from the fire.

They propose that this will do a more effective job of lateral heating, and keeping bonfire attendees warmer as they sit around the fire. They’ll always be fighting that hot air rises, but this may provide more warmth to people that are 0-36 inches from the fire pit.

There are different ideas on what they can do with the space where the radiant opening is. In some embodiments they suggest putting a screen there to add structural rigidity and safety, in others they put a sliding window to open and close the radiant opening.

Secondary Burn

With the radiant opening, it shortens the height of the outer wall that creates an air gap for pre-heating air. That means that there is less of an opportunity to pre-heat the air being fed into the top of the fire pit.

The patent suggests that there still can be a secondary burn with shorter air gap, but offers different designs, including having no secondary burn at all. I think they’re just covering all the different potential designs with the patent because having the secondary burn is a key characteristic of a smokeless fire pit. I’m sure there is a minimal height for the air gap though where it becomes no longer effective.

Lateral Heat

With all of the various improvements to fire pits and fire pit accessories that Solo Stove has made, it’ll be interesting to see where they’ll go next. Effectively increasing lateral heat is a big challenge but one that would improve the user experience with their fire pits. Innovation has been important for Solo Stove’s growth, so hopefully this latest one (if it’s released) works well and gets them back on a good trajectory.