First post: fighting a wood furnace.

[Driver4r]

I have multiple inefficiencies working against me, lack of wall insulation, not 100% air tight, so basically a really old house, except Mines a pole shed.

The roof is insulated, and the walls are housewrapped under the tin, but im struggling to maintain 50*. I got the stoker fan to cycle now, befor it would only do 10* over ambient, yesterday she got to 23* over ambient(50*) thermostat is set at 55*.

Furnace is outside the shed under a lean-to, its plummed to recirculat the air, squirrel cage blower is inside the shed, blows out, through the furnace then back in through a single 10".

The unit is an old Fox fire furnace, ive been burning anything i can find which is another inefficiency, alot has been Chinese elm. Last night I threw some hedge in and it lasted ALOT longer, but still not throwing out the heat i want. I have the squirrel on the lowest speed.

Looking for insite.

 

[cookies]

aren't those supposed to be in the living space to promote radiant heat like a potbelly stove with a fan? have you changed the fan to a higher cfm setting? measured the output air temperature? Having lived in a "arid" home for several years I most certainly remember the most difficult heating issue was having enough btu's to overcome the losses via floors/walls/windows/ceilings and even the chimneys. My fix was to run a kerosene 50,000 btu forced air heater in a exterior open doorway to knock the chill out of the house then maintain the heat with the fireplaces and other devices and even use visqueen/masking tape partitions to block off rooms to keep more heat in if the temps got real low. I'll never forget the first winter there, burning old furniture/clothing/trash and any wood i could drag in from the adjacent forest. The following year I grabbed the heaters and a chainsaw and all was well.

 

[Driver4r]

aren't those supposed to be in the living space to promote radiant heat like a potbelly stove with a fan? have you changed the fan to a higher cfm setting? measured the output air temperature? Having lived in a "arid" home for several years I most certainly remember the most difficult heating issue was having enough btu's to overcome the losses via floors/walls/windows/ceilings and even the chimneys. My fix was to run a kerosene 50,000 btu forced air heater in a exterior open doorway to knock the chill out of the house then maintain the heat with the fireplaces and other devices and even use visqueen/masking tape partitions to block off rooms to keep more heat in if the temps got real low. I'll never forget the first winter there, burning old furniture/clothing/trash and any wood i could drag in from the adjacent forest. The following year I grabbed the heaters and a chainsaw and all was well.

Yea, and here it gets well into 0 and below. Another late winter this year, and I didn't get the furnace untill late in the year **early dec**.

So the wood is whats been around or cut this year.
For the frigid days and when the furnace is pissing me off I have a 165kbtu heater I use. But I hate having intermittent heat, I would rather have the building consistent. The kerosene heater will get the building to 75, but its superheating the air at a much faster rate.

Next winter I plan to have alot of scraps to burn both cedar and oak off my sawmill. But this year I'm extremely limited to whatever I can find to cut.

And ive been debating about some sort of fire retardant insulated blanket to try and keep more of the heat IN the furnace, rather than radiating through the walls. And also a bigger stoker fan.


And yes. It would be more efficient inside the shed, but I recently had an encounter with a shed fire and lost quite a bit and I'm a bit hesitant.

 

[cookies]

wet wood will make you cold ! I used 3 oil filled heaters to maintain the heat in about a 700 sqf living area. The oil filled radiators take forever to heat up but work very well and even come with digital thermostats now. I kinda wonder if you could use lump coal or supplement some for wood to get higher temps than using wet wood. I used to stack some wood in the house to help dry it out for a week and it really worked well.

 

[Driver4r]

wet wood will make you cold ! I used 3 oil filled heaters to maintain the heat in about a 700 sqf living area. The oil filled radiators take forever to heat up but work very well and even come with digital thermostats now. I kinda wonder if you could use lump coal or supplement some for wood to get higher temps than using wet wood. I used to stack some wood in the house to help dry it out for a week and it really worked well.

Most of what I have is fairly dry, dead trees laying around i cut up, neighbors pastures etc.

And im heating 1200sqft.

 

[sean donato]

Just because its laying around doesnt mean its dry. The first year I bought my house, i was rather unprepared for the burn season, and resorted to the same type of thing. Laying dead trees. Mostly off the ground. I was surprised to see how much moisture they had after being dead for years. Can be a killer.

 

[moresnow]

@Driver4r We appreciate your efforts, struggles and good intentions using wood heat. Sounds like it would be very beneficial for you to take a few hours online to research seasoning firewood correctly. I believe you will get your eye's opened. Sounds like you have lots of opportunity to improve your heating system/routine. Good luck, stay warm and be safe.

 

[ChoppyChoppy]

Without insulation in the walls, I'm sure the heating requirements are quite high.
What is the R-value on the ceiling?

House wrap I suppose is better than nothing, but it's not much. Is the building open studs?
Insulation goes a long way, though a vapor barrier alone makes quite a difference
(IE airflow stopper).

A decently insulated 1200 sqft space should be easy to heat. I wouldn't try keeping a barely insulated tin shed heated unless costs weren't a concern.

Be careful of using a salamander heater.... put a CO detector up at least.

 

[Pronghorn]

As the saying goes, wood doesn't start drying until it's split and stacked. You can get by with suboptimal wood by mixing in some compressed sawdust blocks, but it sounds like your main problem is bleeding heat out of the building. You'll probably save money both short and long term by sealing and insulating.

 

[fields_mj]

If you are near the furnace, can you feel a noticeable amount of heat radiating off of it? If so, then the building is just loosing more heat than your furnace can generate it.

Since the furnace is outside, you're not only loosing the radiant heat, you're also cooling the hot air that you want to blow back into the shop while it's still in the furnace.

If the furnace just doesn't seem to get hot, split your pieces smaller and only fill the furnace 1/2 full to start with. The increased surface area will cause the wood to burn a lot faster, making up for some the efficiency lost to excess moisture. Once the furnace is hot, you can add some bigger splits but you still won't be able to burn the big pieces that give you long burn times without decreasing your heat output. Your burn times will be a lot shorter, but you'll get heat. This isn't increasing the efficiency, it's offsetting it by consuming wood at a faster pace. This is a trial and error process that requires somewhat consistent monitoring until you get a process worked out. If you go overboard, you'll over heat the furnace and damage it, potentially resulting in one of those shop fire's you're worried about.

Not sure how the interior of the building is laid out, but once you're able to figure out how to get some heat, I would recommend putting a fan in the far corner and blowing the cold air back towards the intake. Cold air is more dense and a LOT easier to move than hot air. Moving the cold air towards the intake will allow the warm air to circulate into that area.

Good luck!

 

[brenndatomu]

Possibly a poor furnace design? Wet wood, an inefficient outdoor installation, and high heat load = cold home.
BTW, what is a "stoker fan"?

 

[brenndatomu]

squirrel cage blower is inside the shed, blows out, through the furnace then back in through a single 10".

A single 10" is not much airflow unless this is a small low BTU furnace...and not much airflow for the building you describe either. Then the return air duct should be ~20% larger than whatever the supply duct is too.

 

[Driver4r]

A single 10" is not much airflow unless this is a small low BTU furnace...and not much airflow for the building you describe either. Then the return air duct should be ~20% larger than whatever the supply duct is too.

The supply from the return fan is 18x6" rectangle duct. Which should outflow the 10" exponentially.

 

[Driver4r]

Possibly a poor furnace design? Wet wood, an inefficient outdoor installation, and high heat load = cold home.
BTW, what is a "stoker fan"?

The little squirrel cage on the firebox to help stoke the fire to build heat over a short amount of time.

I call it more of a catchup fan. It helps the furnace catch up to a temp drop

 

[Driver4r]

Without insulation in the walls, I'm sure the heating requirements are quite high.
What is the R-value on the ceiling?

House wrap I suppose is better than nothing, but it's not much. Is the building open studs?
Insulation goes a long way, though a vapor barrier alone makes quite a difference
(IE airflow stopper).

A decently insulated 1200 sqft space should be easy to heat. I wouldn't try keeping a barely insulated tin shed heated unless costs weren't a concern.

Be careful of using a salamander heater.... put a CO detector up at least.

The roof is a r19 thats been compressed under the tin/housewrap/plywood/r19/housewrap, so its probably acting more like an r6-r8.

But yes. The sidewalls are only vapor barrier/tin.

 

[Driver4r]

Sorry everyone for the delayed response. I never got an email that people had responded

 

[aokpops]

I have a foxfire ran it for guessing 20 years . I know it likes dry wood in its time was a good furnace I bought it used for 125.00 it owes me nothing . But getting back to burning wood for heat get smarter every year. Figure out what could I do to make it more less work an more energy . I would start nobody is going to heat the outside in winter . The sun can do it and that's about it insulation is king when seeking cilmate control . I would do a small section of living space and button it up as best I could with what I had to work with . Nobody wants to see you cold on this website . I work outside for 33 years last thing I want is a person with a cold house .

 

[Mustang71]

I'm heating right along with minimal effort. It's 18 and very windy here. It was 61 in the house when I got up and now I'm maintaining 69 in the house with a log here and there. 1700sqft raised ranch so 3400 sqft above grade.

3 things.. insulation will fix your issue of heat loss. Make sure the furnace is kept warm and out of the elements. Burn dry wood.

When im having issues getting my logs to light up and burn I throw pallet wood in or scrap wood. That stuff is all dried and burns fast and hot. That can help get wood going even if it's a bit wet.

 

[Mustang71]

As a residential hvac installer, your size house would heat fine with a 45k btu gas furnace or an insulated garage a 45k btu gas hanging heater. Now that's in Buffalo NY. We don't get much colder than 0 but that being said idk what you want out of a wood fired appliance that sits outside. Basically you are trying to heat the outside.

 

[esshup]

I noticed a good 10-15 degree difference inside the house when burning dry seasoned wood compared to wet wood that was laying outside but dead for 2-3 years, even wood that is cut/split/stacked outside, if I didn't have a roof over the wood. Burning damp wood, I have to turn the air intake all the way open, split the wood half the size that I normally would split it and it still struggles. If the wood has 12% max 15% moisture, then I can choke down the air considerably and the house gets warm in a hurry, plus the burn times are a lot longer. It takes 2 years for Oak to season if kept out of the weather and split/stacked.

Insulating the building will help immensely.