How Much Coal Is Wasted Per Day Through a Barometric Damper?

Negligible and difficult to quantify. The entire volume of heated air in a structure is trying to and to varying degrees succeeding in rising out of the structure and pulling in fresh cold air. The Baro is essentially using that air,........to a greater or lesser degree. Remember, a coal stove, like a wood stove, is a space heater. The fact that a coal stove can and does heat some homes entirely even with the use of a Barometric Damper is,.....remarkable!

In a nut shell, the lack of either will cost more coal than picking one or both
Hahaha. Pick both, save more

Just kidding. Nobody liked the consistent burn theory lol?

To decide which one is better, I think it depends
On the situation.

In a basement installation where air infiltration isn't a big deal, the barometric is probably gonna cost less coal. In a living space installation the manual could be a better option.

What about no damper in the case of a thermostat controlling air intake for combustion?

I read somewhere that in even the very tightest of modern homes the air turn-over needs to be at the level of at least one complete change-out of the air every 3 hours at a minimum, and if it is less than that it is considered to be very unhealthy for the occupants.

If a home has 2,000 sq-ft of floor space and 8 ft. ceilings that is 16,000 cubic feet of minimum air leakage that is actually required by the home every 3 hours (not counting the basement). That comes to 5,333 cubic feet of infiltration by cold air rushing in and the same volume of heated air drafting out, stove or none. For an older home of comparable size the air infiltration (also stove or none) could be perhaps 50% more than the requisit minimum for modern tight homes, or about 8,000 cubic feet per hour.

Every pound of coal that you burn requires the draw of 123 cubic feet of air through the stove to combust it completely. If you are burning 50 lbs. of coal per day thats only about 256 cubic feet required per hour going through the stove, into the coal, and out the chimney as combustion byproducts vs. from 5,333 to 8,000 cubic feet or more going out of the home every hour due to all of the homes other leaks and natural drafts. Even if allowing for 15% more air than is required in a perfect world (as I've read that real world combustion is best when 15% excess air is present) that means that only about 300 cubic feet of air per hour are drafted through a stove that is burning 50 lbs. of coal per day.

Though this excercise does not measure how much a home loses to a barometric damper, it might be in the ballpark of the amount being consumed through the stove, and if so It seems negligable overall vs. the natural turn-overs of air for a home.

franco b wrote:What about no damper in the case of a thermostat controlling air intake for combustion?

Some people argue this, but my Hitzer has the bi-metal damper and even with that I will hit 500-600 degree stack temps getting fresh coal going(well over -.1 on the mano). Even with my MPD I feel I am losing too much heat up the chimney. I do have a baro waiting to be installed. It's strange how much different one person's setup can perform from the next person's setup.

I like the bimetallic thermostat in theory. Simple and effective way to control burn in a tight stove. Again, it is drawing a small volume of air from the huge volume of air naturally and necessarily moving in and out of the house. What the flapper can do for draft, I'm not sure.

Well then it seems we have made some progress. I was wondering this morning how much loss thru a barometric is relative to average loss of a house overall. Based on that, I change my mind. A barometric damper is superior

Nice work Larry

If an older 2,000 sq-ft home normally drafts 8,000 cubic feet of 70 degree air out per hour, and it is -20 degrees outside, then it is simultaniously drafting 8,000 cubic feet of -20 degree air in per hour.

Air weighs a nominal 0.0807 lbs. per cubic foot. (give or take, this being only an average)

The difference between 70 degree air drafting out and -20 degree air coming in to replace it is 90 degrees.

8,000 x 0.0807 x 90 = 58,104 BTU's of output required to heat the home when it is -20 degrees outside. At 65% efficient, a stove (furnace, boiler) of about 90,000 BTU's rated input would be required for that -20 degree day. This seems to be in the ballpark.

Tonight, I'm going to go outside with my manometer and stick the probe in the house and read what the draft of the house is,......just for giggles Anyone care to speculate what I'll find???

franco b wrote:What about no damper in the case of a thermostat controlling air intake for combustion?

I'm not totally on board with an automatic primary air control since it doesn't control the secondary air with the variable pressure the stove would have.

Also, I'm wondering if the stove output temperature oscillates, even if it's not very much.

"................ I read somewhere that in even the very tightest of modern homes the air turn-over needs to be at the level of at least one complete change-out of the air every 3 hours at a minimum, and if it is less than that it is considered to be very unhealthy for the occupants. ..................... "

Ok, I'm safe ! This old house , . . . it's more like 3 minutes !

Paul

Carbon12 wrote:Tonight, I'm going to go outside with my manometer and stick the probe in the house and read what the draft of the house is,......just for giggles Anyone care to speculate what I'll find???

I guarantee you see a negative value on the first floor and a positive one after you get on a ladder and measure the second floor. Better yet, open a window downstairs, tell me air comes in then open one upstairs and see if air goes out lol.

Carbon12 wrote:Tonight, I'm going to go outside with my manometer and stick the probe in the house and read what the draft of the house is,......just for giggles Anyone care to speculate what I'll find???

I'm guessing that you will find that the manometer isn't sensitive enough to register anything.

Granted it won't be much but I speculate it will show.

My tiny brain can't wrap around much so I keep it simple for myself: Would I rather have 72 degree air go up the chimney (barometric damper), or would I rather have 500 degree air go up the chimney? (no barometric damper).