for greenhouse, or any does large duct size matter?

new to this. love your info. for our greenhouses, I'm considering 12" culverts for ducts. Is this problematic, or possible? I've considered maybe the diameter too large for heat to be efficient, the thickness in case heat cannot warm everything up enough, being corrugated shape for gases and their travel, being galvanized in case their is any bad chemical-type mixture, and finally, whether the ratio of sizes might throw the whole efficiency factor off, due to length or otherwise. I inherited these from a local construction job, and was thinking re-use could be good in this way. However I do not want to shoot myself in the foot before I even begin. If nothing else, I could scrap them for cash toward the proper material. Please help, I need to make fast decision, - in fact, today. Sorry... Absolutely love this place of yours, and have learned LOTS about EVERYTHING!!

Judith Keisling : Scrap them, about all of them are wrong for you ! Consider saving a 5' to 8' chunk will get right back to you - have you got '' The Book '' Yet ! big AL?

Judith Keisling : Never Judy ? You need to go to rocketstoves.com to get your PDF Copy $15 of Evans' Great book Rocket Mass Heaters, there is STILL No other book in any
language with more Rocket Mass Heater Family Information. (and I don't make a dime )

Please go to - Villagevideo.org/products/rmh/scenes/ , to watch 3/8th of a video that will be soon the best video of a complete R.M.H. build, And don't trust any thing else
that you see onU-Tube, there is a lot of crap out there ! yours in haste Big AL!

awesome. I'll do that. If you mean the one by Ianto, not yet, that will be one of my 1st purchases with the proceeds. Really want the videos too, so I can learn everything. Great help. Thanks again

oh, I see. Even better... I'll do that 1st, big thanks

Judith Keisling : One of my first jobs and the most important one is to introduce you to Ernie and Erica Wisner the Couple of instructor/contractors that you see in the video
I sent you to, they are off doing a back to back double weekend Rocket Mass Heater RMH, workshops where their students will make a total of 5 I think RMHs, and
learn to make their own Cast-able Core to take home with them as the heart of the students next build at their individual home places !

They have been very busy, and absent from these pages but we do expect them back soonest ! In the meantime you can visit their site as long as you promise to visit and
Not shop ! go to - ernieanderica.info and enjoy !

Come back here any time, with over 19,000 fellow members world wide you can come ere 24 / 7 and expect a timely answer, not always as timely as today but almost
always in 24 hrs BIG AL !