Experience with rocket fireplace mass heaters?

[penney_mc22]

My hubby and I have been doing a lot of research lately into alternative heating options as we're building a small cabin on an old family property. I keep coming across these rocket fireplace mass heaters. Has anyone here built or installed one of these? How much wood do you actually use in a day to keep a space comfortable? What are the biggest challenges you ran into during the build? We've seen a ton of different designs online, and we're a little overwhelmed with where to start. Any advice on design choices or materials would be hugely appreciated. We're trying to figure out if this is a practical and reliable long-term solution and if we can handle this as a DIY. Thanks for all your help!

 

[Mean|Earl5]

Built one in my workshop last year. Burns a third of the wood compared to my old stove, once the thermal mass is up to temp. The biggest challenge was sourcing enough firebricks and getting the riser insulated properly to reach high temperatures. For DIY, you can start with a J-tube design and keep the footprint simple. What's your climate like in winter and are you planning a cob bench or vertical bell? This'll affect how much thermal mass you'll want.