With the energy efficiency tax credit in mind I was browsing woodstoves for possible replacement of my 20+ year old jotul 8 (with badly distorted and costly to replace burn plates inside).
I saw a jotul f500 oslo that looked like a really nice upgrade from my old model 8. One of the features I was especially interested in was an outside combustion air kit that used a vent pipe to run outdoor air directly up into the center of the stoves floor.
In theory the outside combustion air sounds great as it should eliminate the vacuum a typical wood fire creates that sucks cold air in from any cracks or gaps in the house.
I am curious if anyone has tried both outside air intake vs burning indoor air and noticed a significant difference.
When we took out my grandma’s woodstove and put in a direct vent gas fire it was amazing how much less dust there was in the entire house. It led me to speculate that the wood fire was pulling air in from under doors, around windows etc and introducing a lot of additional dust into the house.
My latest thought is to keep the old Jotul 8, replace the burn plates and add a outside air vent immediately under the stove with a low volume blower on it drawing air from a relatively dust free area outside of the house to slightly pressurize the house. This would supply any combustion air to the stove as well as providing the make up air at the warmest point in the house rather than letting it draw air from the perimeter which is generally the coldest. It also seems like if one cracked a window at the far end of the house the warm air would be carried that direction by the positive air pressure in the house escaping out that window. I could put a thermostat on the blower adding fresh air under the stove to shut off when the stove dropped below a certain temp.
If more appropriate I could also just cut a hole in the bottom of the existing woodstove and add a flange to pipe outside air in under the double floor. I would have to put a damper in the pipe to control airflow but I think it could be done with a little ingenuity.
I live in a pretty mild coastal climate in Northern California (Santa Cruz) in a late 1800’s 1000 sq ft house that is gradually getting insulation added wall by wall and hopefully the attic this winter. It rarely drops below 40 degrees at night and daytime temps are usually above 55degrees. The architecture of the house doesn’t lend itself very easily to replacing the big single paned double hung windows that most likely leak a lot of air. There are 5 – 3′ by 6′ double hungs. the rest of the house has marvin integrity windows. The interior walls are tongue and groove redwood that has allowed a lot of air movement in the past but as we rehab each room we caulk every joint between the boards prior to paint so when we are done the unintended air changes in the house should be much less frequent.
What is the verdict?
Buy a new Jotul with outside air (online reviews aren’t very inspiring)?
Don’t mess with it and run the Jotul 8 til it fails entirely?
Add a fresh air vent under the stove?
Add a homemade outside air intake to the old Jotul? or do this along with pressurizing the house with fresh air under the stove?
Thanks,
Karl
Replies
Fix the stove, correct the problems with the insulation envelope, look seriously at get better windows.
What McPlumb said, but also go with the outside air source as the first step of the weatherization project.
Heck, even women are good at figuring that out (obscure reference to his air gap question response....)
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Given the mild climate and a working device, I wouldn't change heating systems. Consider a dedicated comb air intake if it is relatively easy to install. If you want control, though you should have it equiped with a motorized damper so it is closed when the stove is off. Do not use e.g. a backdraft damper for this purpose. Combining a vent fan? ... optional, I suppose. You'd want it interlocked w/ your exhaust fans, it seems, though, not your stove as it's intention as you implied is to provide vent air to compensate for exhaust fans.
Don't connect anything to the stove itself, though ... e.g. attempt to run the comb air to the firebox. Such things void the UL listing of the stove.
That's my 2 cents.
I agree with the others in that addressing the
building envelope will bring the greatest returns.
BUT!
The Gov. rebate is an excellent deal.
1/3 off is no joke. We just bought the Jotul F600
with a chimney liner kit installed.
$4000.00 minus 30% = $2800
That was to good a deal to pass up.
So, both maybe?
Everybody, thanks for the input. It sounds like no one is a big proponent of outside combustion air.Henley, How do you like your f600. Did it offer an outside combustion air kit/did you use it? I think the new Jotul's look really well designed with fire brick liners and easy log loading. I was a little disappointed with the online reviews. I read complaints about minimum burn rate, maximum burn rate, and smelly offgassing. My main concern is good burn control and it sounds like you get more control with the older pre catalytic Jotul's.Karl
An outside air source is a must for a wood stove.
Don't know if any of your ideas are the way to go though.
The air is supposed to go directly into the stove, with a thermostatic damper to close it when the stove cools.
Joe H
But you can't just pipe a combustion air intake into a stove. Any modification of the stove will void the UL listing. The stove has to be designed to accomodate combustion air 'directly into the stove'.
So, far I love it. It is replacing a very old mid sized Jotul. So i
guess it's a good comparison for you. It does have an optional outside air kit but the sales man
wasn't a big fan so I decided to wait and see. The burn time is excellent, altho with a stove this big
that should be expected. Minimum burn rate? Well I put the darn thing out the first time I closed it down.
Really, a full blown mature fire-out. Maximum burn rate?
They don't roar like older leaky stoves. The thing is
like an all wheel drive car. It works very well but your not
going to have the control like in a four wheel drive in unusual
conditions.
operating it is a no-braner. For better or worse. But to say
you have less control wouldn't be true. You can choose the burn
rate with great accuracy. It's just that there is only one
simple lever, but the system works very well.PS
All the Jotuls are non-catalytic now
Thanks for the good report on the Jotul.You have me reconsidering a new one again and I have a handful of questions for you.Does the glass stay consistently clean? If it does get sooty does it burn the soot off or do you need to clean it?What kind of wood are you burning and how dry is it?What led you to the f600 vs the f500?Do you use the side loading door exclusively or does the front door still get regular use?How many fires have you burned so far/How many weeks or months in use?Do you like the ash drawer under the firebox? I seem to recall reading a review that had issues with it???One feature I was really impressed by was the tight clearances to combustibles.Thanks,
Karl
Well I've only had it for about two months but as I am
in the middle of a massive remodel it's our only heat. So
I have a fire most every day.
The glass stays much cleaner then the old Jotul but is not
perfect. I haven't cleaned it and don't need to yet. I collect my own wood on the property so it's a pretty good
mix of hard woods. All seasoned well over a year and some was
down a while before I got to it.The F600 has nice double doors for viewing and the cost difference
isn't all that great between the two. But, mostly I didn't want to under buy. This house has a lot of glass and cathedral ceilings.
Coupled with 1800sf in January in Central New York, That pointed me towards the big fatty. I started out only using the front doors but lately I've realized
the side load is easier. You don't need the detachable handle and
tossing the log in lengthwise makes more sense. I can't imagine what would be wrong with an ash pan. Works fine
and is kind of a luxury item anyhow. I empty it every other day
and haven't had any issues. Like I said this is my first winter with the stove so I can't tell you long term opinions yet.
In the PNW ... energy codes required combustion air intake dedicated to the stove. This posed problems in terms of the practicality (i.e. how to control it). Not sure how the codes there now work. With 'tight' construction, any combustion device can be a source of problems ... particularly wood stoves as they can consume a lot of combustion air at times and you don't want it to backdraft when you turn an exhaust fan/range hood on.
Here is my plan. Combination firewood bin and outside air source in the form of a large drawer in the outside wall next to the stove. With the drawer pulled to the inside, it looks like a firewood box. To load with firewood, pull the drawer to the outside of the house, load, and slide back in (no tromping in and out with armloads of firewood and snowy boots). Drawer can be opened as much as needed for combustion air (even 1/2" would be plenty). Closed the drawer would have weatherstripping to seal the opening. Plan on using sashlock hardware for security, when stove not in use. :o)
Cheers,
Bass
Great except when you want to stoke the fire and walk away (or sleep), then the combustion air doesn't take care of itself.
It would be rather easy to use the wood drawer assembly (built into a bench seat with a lid that opens to access firewood) to provide a chase for a combustion air duct (the sides of the bench that house the drawer guides can be made thick enough for the duct). The duct could also be dampered so it could be closed when the stove is not in use.
Karl, I am in Kansas (north central) and have used a Jotul F600 firelight for two years as the primary heating sourcse (propane forced air backup) in a 110 year old farmhouse out on the paraire. I did not hook up the outside burn vent, but am still considering it. The house is leaky enough and will take re siding and windows before I can fix that. I have not noticed any additional drafts with the stove.
The stove is great, with hardwood, it will burn from 11pm until 6-7 am with enough coals left so all you have to do is put some kindling on and away you go. We have used it and fired straight from Dec through Feb-march with a fire continuous. The glass will get dirty, stays clean for 2-3 days max. Burn control is easy, one lever on front. Ash pan is easy to dump, no problems there. I got a painted stove, if I were to do over, would get the porcelin finish. Stove was the best investment I ever made. It is easy to operate, we burn 3-4 cords a year. I used to live in Santa Rosa and cut and burned then, have lived in the Midwest now for the last 23 years, using wood is much more satisfying than natural gas or Propane, the only thing better would be solar radiant floor with wood stove.
Good luck,
Steve
Interesting, My glass is staying cleaner for a lot longer. Must be type/condition of wood or user habits. Did you get the optional screen? We ordered it (hasn't shown up yet) but I kind of doubt
it will see much use.
No, no screen, we use it as a heater, no open fire, always load from the side unless I have a huge log that I didn't feel like splitting.
Steve
Steve, Thanks for the input on the newer Jotul's. I am glad to hear between you and Henley a pretty strong vote of confidence in the newest version of the Jotul.I am surprised the outside air connection isn't more popular, It seems like a great feature. For some reason the sales people and installers in my town are kind of ho hum about it.I think you made the right choice going with the painted over the porcelain finish. I used to have an old Jotul 3 with porcelain and my mom has a jotul 8 with porcelain. Once it chips you are out of luck, it will always look shabby. You can take the rustiest, dirtiest raw cast iron stove and spend an hour starting with a rotary wire brush and ending with a can of stove black and have your stove looking brand new.Karl
Before you convert the existing, check out the prices fro replacment parts and find out if it even possible to add intake vent to your existing stove. If you are in Santa Cruz, what are the restrictions on wood stoves. My memory is that they have pretty much outlawed wood burning stoves within city limits(am I right?). I believe the newer jotul have a single double pipe that serves both intake and exhaust, meaning larger dia pipe through wall/ceiling
From my memory, jotul is more of a enclosed and they didn't have much if any glass.
Have you considered a gas(natural or LP)?
I have installed a few Lopi and they have been great.
Direct intake is soo much nicer and cleaner. If you want glass fronts, it will keep the glass cleaner too.
In Santa Cruz open fireplaces may be banned from new construction but there are several shops selling and installing woodstoves.The Jotul has a single wall 6 inch flue and a 2 or 3" optional outside air intake that enters from the underside of the stove.The older jotuls don't have the outside air intake option and I like a gas fire for cleanliness but I have thousands of cords of eucalyptus on the property that I can't pass up an opportunity to burn for heat.I like the lopi's as well but the style of the jotul fits our home/decor better. Thanks for the input,
Karl