Doghouse?

therealdbeau

Member
Oct 16, 2018
135
51
73
VA
Can we talk about doghouses? I think this is a pretty well accepted name for air inlets at the front bottom of the firebox.

I'm trying to understand the intended purpose of this feature because as far as my stove goes I can't make head or tails of it. I've successfully run my stove with and without this air jet blocked off and while my hunch is that I get slightly longer burn times with it blocked off it's too hard to say.

Anyway, my thoughts are that the doghouse is designed to do one or more of a few things such as introduce air to the bottom of the firebox to more completely burn the fuel. Or help direct the air-wash air and create a sort of swirling air path around the firebox. Maybe it's just there so keep the fire from smoldering as kind of a safety for inexperienced stove operators.

So, does your stove have doghouse air inlets? Are they adjustable? What do you make of it?
 

Eureka

Member
Feb 4, 2018
246
154
73
NW Wisconsin
I know that on my stove it only seems to let a noticeable amount of air out the doghouse when the intake is open over 75%. Like a boost air for starting although some air always is allowed in.
 

brazilbl

Member
Aug 24, 2017
69
38
33
El Dorado County, CA
Though the store did not give me a "chefs tour" when I got my wood stove, I found out pretty quickly the function of the "doghouse" and the lever on my Regency H2100. Pull the lever out and more air is shunted through the doghouse. Close it off, and you will/should see a dramatic decrease of airflow. As I understand it, one cannot completely cutoff the air completely to the combustion chamber as this is part of the design.

I found that if I carefully place a log right on top of the doghouse, it can facilitate the burn of that particular log by focusing the heat of the burning embers underneath along the surface of the log. If my firebox was long enough, I'd like to try the North-Sough log orientation that can more fully utilize the airflow from the doghouse down the length of the log instead of a perpendicular pass along the log. If one places a single log in the firebox close enough to the doghouse and let it burn, chances are that doghouse will create a tunnel of super-heated gasses that will slowly, but surely bisect the log completely through.

Though I try to keep ashes out of the way of the doghouse, I can certainly imagine that I can take care of that by running a shop vac hose along the doghouse to keep airflow through that free from obstructions (of course, I would wait until the wood stove is completely cool before running the vac! ).

Perhaps this will help to understand the role of the doghouse (at least for me). Looking at the manual, it appears that each wood stove manufacturer designs a air circulation system that draws in outside air and funnels it primarily through the air inlet system, terminating at the opening at the doghouse which focuses the intake air primarily along the bottom of the firebox toward the back. Heated air from the combustion process moves the air from the bottom and back toward the ceiling of the firebox (where some of that is shunted to the class cleaning system, but I digress) where the gasses that are not burnt are rerouted through another air system to pass through the secondary burn tubes to ignite the gasses to further complete combustion and will help to funnel the exhaust out of the wood stove up the flue.

Of course, stoves that are way old or may have catalytic combustion technology work differently than what I have observed with our stove.

Somewhere I read that people that observe the work of the doghouse during a burn to a "tunnel of love".

Hope this helps!
 

Ludlow

Minister of Fire
Jun 4, 2018
1,048
274
773
PA
I wonder if raking coals to the front as a habit could possibly cause a blockage in the doghouse. Hmm. An occasional vac hose to the doghouse when safe to do so might be prudent.
 

Texas123

Member
Apr 12, 2016
118
22
93
Stephenville, TX
Mine on the Jotul 500 is simple. Wide open is to the right, almost totally closed is to the far left and the more I close it the more the secondary tubes fire in the firebox.
 

Rearscreen

Minister of Fire
Dec 21, 2014
645
233
803
Vermont
I'm glad this question was asked as it's been on my mind. Out of about a dozen stoves I have owned only one stove that had one. It was by far the worst stove I ever operated and lasted a total of 2 weeks of operating it before I was on the phone ordering a new stove. Why would any air inlet be at the bottom where it will inevitably get blocked?
 

therealdbeau

Member
Oct 16, 2018
135
51
73
VA
Mine on the Jotul 500 is simple. Wide open is to the right, almost totally closed is to the far left and the more I close it the more the secondary tubes fire in the firebox.
This is interesting because I had a hunch that maybe the doghouse air functions as some sort of balance to the secondaries.

It's hard for me to test this theory because my doghouse air isn't adjustable and the only way to block it off is to reach my hand under the stove which isnt really possible once it's hot.

My manual says:
"A primary air hole located under the front brick provides air to the coal bed. (Figure 12) This hole should be cleared of ash for proper performance."

However like I said I've intentionally blocked off the doghouse air and it ran just fine if not better so I just don't know what to make of it.
 
Last edited:

brazilbl

Member
Aug 24, 2017
69
38
33
El Dorado County, CA
  • Like
Reactions: ispinwool

ColdNorCal

Member
Mar 6, 2018
231
66
73
Nor Cal
We rake the coals forward in front of the small hole and it never clogs. The draft draws plenty of air though the hole and it literally makes a hole through the coals and creates a path though the ash. The small air supply certainly helps turn all coals to ash and probably is important for the initial primary burn startup cycle..

Also, when the fire is strong I can hear the air jetting through the hole. I thought about blocking it just a little to see of it changes the secondaries I just have not done it as their are never any coals left in the morning.The stove burns it all up nicely.
 

webby3650

Master of Fire
Sep 2, 2008
10,188
2,995
803
Indiana
This type of air inlet works really well on most stoves. The only time I’ve ever seen one clog up was on a Hearthstone. Other manufacturers have figured it out.
 

Adabiviak

Feeling the Heat
Dec 7, 2008
356
45
303
Sierra Nevadas, California
The dog house in my stove has its own separate control, and is the "primary" source of air. There are secondaries in the ceiling tubes, and igniters in the back (that are shut off once the wood is going), which leaves the output from the doghouse as the main throttle. If that gets choked off, the draft just makes up the difference through the ceiling/door secondaries, which is a tad slower, I think. With the throttle open, a little jet of air shoots out there (with the secondaries still available for duty).

I align my splits north/south such that the air from the doghouse has a little channel to blow down and ignite the nearby wood edges unimpeded.
 

Sawset

Feeling the Heat
Feb 14, 2015
460
248
303
Palmyra, WI
The doghouse here on the Oslo has never clogged. Actually, very little gets in even if burried in ash repeatedly for weeks. It is an air inlet, with air coming in, not out, so the answer lies somewhere there. Here it provides an effective way to regulate burn rate, by giving excess air at startup when open, or only secondaries when closed. It doesn't open up much in the way of air flow, but there is just enough of a range to effectively regulate the burn rate. The stove appears to be finely tuned in that regard.
 

firefighterjake

Minister of Fire
Jul 22, 2008
18,847
4,849
803
49
Unity/Bangor, Maine
I have yet to see the air coming in to the stove get blocked by ashes or coals with my stove.

The only thing I do on an annual basis is take apart the doghouse, vacuum up a bit of fly ash that has worked its way into the mechanism and then apply a liberal amount of graphite powder to keep the slide mechanism gliding nicely all year long.

As others have said . . . the dog house air in the Jotul dramatically affects the secondary.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
18,311
4,263
803
central pa
I'm glad this question was asked as it's been on my mind. Out of about a dozen stoves I have owned only one stove that had one. It was by far the worst stove I ever operated and lasted a total of 2 weeks of operating it before I was on the phone ordering a new stove. Why would any air inlet be at the bottom where it will inevitably get blocked?
The majority of stoves on the market have some air introduced in the bottom front. It is extremely rare to have it clog. What stove was it you gave up on in 2 weeks?
 

Seasoned Oak

Minister of Fire
Oct 17, 2008
6,313
1,315
803
Eastern Central PA
I try to stack the wood so its forms a tunnel front to back over the dog house, to get the air under the wood load. Also when not removing previous days ashes at least remove ashes from area of dog house air hole. Never had one block. A good stream of air come out of that hole ,looks like a cutting torch sometimes.
 

brazilbl

Member
Aug 24, 2017
69
38
33
El Dorado County, CA
You know, its nice to see someone chime in there and state things so clearly. Mr. Oak, there's a reason you are a "Minister of Fire". Your explanation of the utility and benefits of the doghouse is spot on. Occam's razor! The simpler the explanation, the better!
 

Rearscreen

Minister of Fire
Dec 21, 2014
645
233
803
Vermont
The majority of stoves on the market have some air introduced in the bottom front. It is extremely rare to have it clog. What stove was it you gave up on in 2 weeks?
Sorry, will not divulge lest I get the wrath of the hearth. But I think the Avatar may give a clue.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
18,311
4,263
803
central pa
Sorry, will not divulge lest I get the wrath of the hearth. But I think the Avatar may give a clue.
I am just wondering why you would give up on a stove in only 2 weeks. That is nowhere near enough time to learn a new stove
 

Rearscreen

Minister of Fire
Dec 21, 2014
645
233
803
Vermont
That is nowhere near enough time to learn a new stove
My girlfriend owned the said stove for 5 years then I came on the scene having owned/installed many quality stoves and had a solid understanding. As a matter of fact I did some gasket work on said stove to get it up and running correctly. As far as nowhere enough time, the Progress was a snap and was an easy stove to operate. The said stove, same flue/ hearth etc was hard to start, always was, according to girlfriend, and without overheating went through wood like crazy. 5 cords every winter. Progess half that and much warmer. I made the right decision.
 

Seasoned Oak

Minister of Fire
Oct 17, 2008
6,313
1,315
803
Eastern Central PA
Mr. Oak, there's a reason you are a "Minister of Fire". !
I think that designation comes with a certain number of posts. Not ones level of expertise,but thanx for the thumbs up. One of the moderators would know.