Gasifier Delay (Woodstove for heating)

So before I build a wood powered car I need to take care of more practical need first. Now that I have a welder I decided it was time to build a wood stove to save on heating costs this winter. The house is old and not very well insulated and runs us ~$150 a month in nov dec jan and feb. That’s too much, and that’s only to 68 degrees F. So I started reading and reading. Then after I was satisfied with a more than necessary ‘perfect’ design I started building. I am sort of one of those innovation/ efficiency chasers. Instead of a quick and dirty get it done keep us warm here’s what I got.
I will be using split wood for fuel. 18"long by 4" square. Plus or minus a couple inches. Maybe an extra thick log just before bed.

Pic. 1 is The design idea and working hypothesis
The rest of the pictures are in various states of building
The last picture is the inside of the door channeled for a fiberglass seal.

What I am wondering or asking the experts is there anything I should add? Mostly how’s the position of the secondary air inlet? Maybe a touch lower?
I understand it would be better if the secondary air could be preheated. Practically I can’t figure any easy way to make it happen. Any suggestions?
I understand that chimney length (at least 13ft) and any turns (less bends = better) in it are a factor.

-Eric Cartier

Hi Eric,
I found myself in the same situation as you, needed to heat an old 1200 SF farm house that has no insulation and after much thought I chose to build an outdoor wood boiler. I put it in service three weeks ago and so far I’m really happy with it, I am attaching a pic…
Looks like you are well underway with your wood heater project, I have a few questions…
How many Square Feet of living area do you need to heat and where do you plan to place the wood heater in your home?
What type of heating are you using now?

About 1000sq ft. We are using a forced air natural gas furnace right now. The plan right now it to put the stove in the dining room. Its not optimally centerally located. The idea is that it will save us some money on heating, although we’ve accepted the reality that it might not replace all of it.

Your wood stove is an interesting design, I will be looking forward to hearing how well it works. It sounds like you have realistic expectations in that you may still need to use the gas furnace some. I used a free standing wood stove last winter and still needed supplemental heat but there is no natural gas here, only propane so that’s why I went with the outdoor wood boiler. It heats the whole house really well plus makes domestic hot water.

That’s really great. Did you build your own or get a kit? My uncle has an outdoor boiler like yours, he likes it alright, he keeps his house at 80 degrees all winter long up in Ohio. Where were at in Mid elevation AZ (5000ft) it gets cold enough in winter that you need heat. Averaging in the teens at night. Its been unseasonably warm this year (avg. 40’s nighttime). A balmy 75 degrees while I was outside welding today! I love Arizona. A blessing to have some extra time to get this thing together. I got the door/ hinging/ latching system done today. Next free day Ill be working on getting the heat exchange box up there. Will post pictures when its daytime here again.

Its getting done. I am so ready to be done with this and get to gasifier building!
Heat exchanger ready to go on
The door, hinges, and latches all function smoothly.

Hi Eric,
Excuse my ignorance. You show an inlet for pyrolysis air and another for combustion air. Are these inlets driven by a fan either continuously or at start up?
Also, is there some sort of shaker needed to get the ash to fall? I am curious because I want something like this for my garage.
I currently have a magic heat for my barrel stove in there now. Do you think this will still help me?

Bill Schiller

Nope no fans, only natural draft for my first experiement.
No shaker either, the grate itself will have many holes in it. On top of the grate Im going to put firebricks, with space in between them to allow air to come up through the grate.
Im not looking for a strong draw through the grate openings, just enough air to keep hot coals going pretty strong to help gasifiy the wood put in above it.
Give it a go if you like the concept. Its going to work one way or another you just might have to do some engineering as you go. See what works and what dosent.
Design it with easy serviceablility. Worst comes to worst steel can be ground and re welded :).
One way or another this thing will burn wood, maybe not exactly like hypothesized but it’ll still make heat.
Ill let you know when it gets done, had the gas furnace go out last week (it is starting to get cold for AZ), and busy with a head gasket repair this week, Hope to get it done soon.
God Bless.

Thanks Eric,
This is the Magic Heat I was speaking of. It gets really hard to heat up the garage when it’s below zero.

Hey Eric,
Did you ever finish your stove? Do you have pictures of it complete? Does it work as expected?

Bill S

No I sure didn’t. It still looks the same as it did in those pictures. Its shaped up to be a warmer than expected winter (nights in the 30 or 40’s days around 50-70). Haven’t needed it since I moved into the new place. Its made of solarcrete and Im only using the guest house (< 300sq ft) and it stays warm all night just from cooking my supper. On the super cold nights I run a little space heater. Not sure when I will re visit the gasifier and woodstove. School is the priority for my money and time right now.