Setting up my studio: some questions regarding ventilation of electric kilns + installing a gas kiln inside

[petrichor]

Hello! I am in the process of setting up my very first studio. I am setting it up in my old mountain cabin and I have high hopes! However, I am a little concerned regarding ventilation.

The "kiln room" will be inside the cabin. the room is the most exterior room, a kind of extended hallway. There are windows, but they cannot be opened. There is however a fireplace in the room, with a chimney. There is one wall and door between this room and the next, which also is a hallway. from there there are doors to the bedrooms and the living area.

The room gets super cold in the winter - down to freezing (0C, 30F). When i am at the cabin i only heat is sparsly, so it seldom reaches normal room temperature in the winter. My main questions are:

1. I have NO idea of how well the room should be ventilated for us to sleep and live two rooms away. is it possible to install some kind of vent that sends the fumes from the kiln up the chimney?
2. does it damage the kiln to be in / and operate in temperatures that low? Will it be VERY engery consuming to fire a cone 7 in such a cold room, or does it not matter that much?
3. I am planning to install an electric kiln but dreaming of a gas kiln too. What extra precaution needs to be done when installing a gas kiln? Can i use the chinmey for ventilation? Can such a kiln be installed inside?

Very thankful for all tips or input!

[Callie Beller Diesel]

With the caveat that my kiln does not have a digital controller that would be much more subject to temperature variations, yes, I am proof you can easily run a kiln at 0 C. Mine is in a metal shed outside. The kiln does start to struggle a bit at  -30 C, and at that point I can’t blame it. We don’t get those temperatures for more than a week or so in most years, and they tend to come at times where I can easily wait to fire. The power consumption doesn’t go up measurably: 20*C difference in temperature matters to human comfort, but not to a kiln. 

It’s not uncommon where I live for potters have kilns in their garages, which are typically unheated and are often uninsulated. A digitally controlled kiln will need to have a temperature reading from the thermocouple of 0 C before it will turn on, and what many do will put a small space heater inside the kiln to warm the area before they begin loading. Once the kiln is generating its own heat, it’s usually fine.

Ventillation is another matter. Even with an electric kiln, you will want to make sure it’s vented properly. As the different minerals loose organic components, those carbonates and sulfates will need to go somewhere, and that shouldn’t be into your home, never mind where you sleep. In North America they sell kiln vent kits for the purpose, but you should check with whoever sells you the kiln about locally available equivalents. 

The only time I’ve seen gas kilns indoors was in institutional settings, where the building was purpose built and incorporated a LOT of venting. Otherwise they should be outdoors, but sheltered from the elements. They emit everything an electric kiln does, plus combustion, plus presumably some incomplete combustion for reduction.

[petrichor]

2 hours ago, Callie Beller Diesel said:

With the caveat that my kiln does not have a digital controller that would be much more subject to temperature variations, yes, I am proof you can easily run a kiln at 0 C. Mine is in a metal shed outside. The kiln does start to struggle a bit at  -30 C, and at that point I can’t blame it. We don’t get those temperatures for more than a week or so in most years, and they tend to come at times where I can easily wait to fire. The power consumption doesn’t go up measurably: 20*C difference in temperature matters to human comfort, but not to a kiln. 

It’s not uncommon where I live for potters have kilns in their garages, which are typically unheated and are often uninsulated. A digitally controlled kiln will need to have a temperature reading from the thermocouple of 0 C before it will turn on, and what many do will put a small space heater inside the kiln to warm the area before they begin loading. Once the kiln is generating its own heat, it’s usually fine.

Ventillation is another matter. Even with an electric kiln, you will want to make sure it’s vented properly. As the different minerals loose organic components, those carbonates and sulfates will need to go somewhere, and that shouldn’t be into your home, never mind where you sleep. In North America they sell kiln vent kits for the purpose, but you should check with whoever sells you the kiln about locally available equivalents. 

The only time I’ve seen gas kilns indoors was in institutional settings, where the building was purpose built and incorporated a LOT of venting. Otherwise they should be outdoors, but sheltered from the elements. They emit everything an electric kiln does, plus combustion, plus presumably some incomplete combustion for reduction.

Alright thanks for your detailed answer! Most people I know have their kiln in the basement, but yes, I cannot imagine that the kiln cares if it is 10 or -10 degrees as long as it is possible to turn the kiln on. The differance between room temperature and max kiln temp is so large anyway.

Yes, the ventilation is a big worry. In the summer, I can open doors and windows, but in the winter I would have to vent the kiln out of the chimney somehow. There are two doors between this kiln room an living areas - BUT one has to go through the room to get to the bathroom and with the opening and closing of doors the air would enter living areas and bedrooms. Again, I don't fire THAT often but it has to be possible to live and sleep in the cabin during firings. Do you think it is possible to ventilate a kiln enough for this use? Earlier I have had my kiln in an industrial room with a window, no other ventilation. So I am absolutely unqualified when it comes to ventilation.

Yes, you are right. I have seen a gas kiln inside, but not inside a house. I just thought - I have a chimney in the room, sooo maybeeee. But I would need years of planning. Just curious to hear peoples initial thoughts.

[Callie Beller Diesel]

The vent systems for electric kilns here mostly involve a 10 cm(ish) hole in either the roof or wall, similar to what a clothes dryer uses. Plus ducting, mesh to keep animals out, a suitable fan and a sheet metal hood that funnels fumes either from the top of the kiln or draws them out through the bottom. So they’re very doable in a situation like you’ve described. 

[petrichor]

1 hour ago, Callie Beller Diesel said:

The vent systems for electric kilns here mostly involve a 10 cm(ish) hole in either the roof or wall, similar to what a clothes dryer uses. Plus ducting, mesh to keep animals out, a suitable fan and a sheet metal hood that funnels fumes either from the top of the kiln or draws them out through the bottom. So they’re very doable in a situation like you’ve described. 

Aha! I have never used a vent, but that sound very doable, yes! I have seen the indirect vents (the hoods) but they require a lot of new air into the room, and i cannot open the windows. i could send in a little air thorugh a crack in the door, but that's all. So you think is is possible to just put the vent tube into the fireplace/chimney?

[neilestrick]

@petrichor How big is the 'kiln room'?

[petrichor]

1 hour ago, neilestrick said:

@petrichor How big is the 'kiln room'?

I am a little unsure but around 100ft2.

When entering the cabin, you first enter a tiny entryway (10ft2) and then this room. The room now function as a kind of entryway too: too cold in the winter to use, and uneccesary in the summer. Poorly insulated. From this room there are two doors: one to the bathroom and one to a new lilttle hallway (!) and from this hallway there are doors to the living room and bedrooms. So, there is a room in between the "kiln room" and the living areas but as a said, people walk in and out so the fumes have to be vented in a way.

I think I believe most in a direct ventilation: a sort of hose close to the exhaust-hole of the kiln. But, I saw on youtube that this tube should be directed upwards to get the best sucktion: I was thinking of just stuffing it into the fireplace...but that is low close to the floor, so maybe I have to make a small hole in the roof. Not too tempting, though.

[davidh4976]

I've used three potteries that had gas kilns inside. Good venting is a must. Unlike an electric kiln, a gas kiln can introduce deadly carbon monoxide into the space. A carbon monoxide sensor alarm is important. It also seems that the heat given off by a gas kiln is a lot higher than an electric kiln. For a gas kiln in a situation like yours, I would suggest putting it outside. I have a small gas kiln in my backyard that I cover with a tarp between firings (no shed). The only drawback to using a tarp is that I have to wait for a couple of days with no rain forecast so I can fire it, unload it, and cover it back up before any rain. I can get to cone 10 in six hours and let it cool overnight. It is a converted electric kiln that can be found by searching for: TDI downdraft kiln conversion 

[Hulk]

Typical direct vent setup* draws a tiny stream of kiln atmosphere from the kiln, which is mixed with much more ambient air in the "plenum" - a box/shape that sits tight against the bottom of the kiln, has the exhaust hose connected to it, and vent holes to draw ambient air. Adjustable vents in the plenum, a decided plus, imo.

* Hence, allowance must be made for "make up" air to enter the space, as the fan pulls (and pushes) dozens of cubic feet per minute out of the room! *

In my (limited) experience, direct vent setups get a lot of the fumes, but not all, which may not be a concern for a small kiln...
 

*like the setups marketed by many kiln vendors

[Bill Kielb]

15 hours ago, petrichor said:

I think I believe most in a direct ventilation: a sort of hose close to the exhaust-hole of the kiln

Does your kiln presently have an exhaust port? If so this is already setup for a passive exhaust system. Post a picturre or tell us the model number.

[neilestrick]

The kiln is going to heat up a space that small, especially if it's a larger size kiln. You may be able to get away with a downdraft vent if it's a smaller kiln, in which case you could run it out the chimney. Downdraft vents can be overloaded if you've got a lot of wax resist in the kiln, though, so it may not be ideal in a space that small where people are living. If it's a larger kiln, I would go with an overhead hood like the Vent-Sure system since it will also pull out heat. I don't know if they're available where you live, or if there's something similar in your area. You may be able to run out the chimney since it's a powered system, but I would double check with the manufacturer. The other option would be to pop out a pane of glass in the window and replace it with a board that you can run the vent through, or use that as a source of fresh air. Any vent requires fresh air coming in for it to work, so you'll need to do that or crack a door and possibly a window in the neighboring room in order for it to work well.

[Kelly in AK]

Off the cuff, if you have a chimney, use it.You'll need a blower/sucker to shunt gasses from the kiln to your existing stack. Long horizontal runs are bad, all exit pipes should have some insulation to keep that column of air hot until it’s free of the buiding. Flapper valves on your building exterior are effective in establishing a one way street..

If you have a downdraft (electric )  vent it may be more economical to just run that straight out the wall.

you definitely want to vent your kinl.

 

[Bill Kielb]

Let me add a caution here. When mixing power vents and a natural draft chimney it needs to be done with good forethought, engineering and or supervision later to ensure it is working as intended. If a combustion appliance is involved, combining powered and natural draft is usually discouraged by most combustion appliance manufactures. Combining ventilation and combustion also presents some real design and operational safety challenges. From a design standpoint under many codes and requirements, these are rarely combined. Again if this is a kiln with a built in exhaust port, Ie Rhodes passive exhaust design, this might be easy to achieve at least as intended by the manufacture.post the make and model of the kiln.

Edited November 28, 2023 by Bill Kielb