How Do You Size a Stove to a House

Post Reply
 
Diesel
Member
Posts: 38
Joined: Tue. Nov. 17, 2009 8:19 pm

Post by Diesel » Thu. Dec. 24, 2009 1:41 am

Is there a formula for sizing a coal stove , or stoves to a house. For example. An easy to remember formula . When calculating how much kerosene or what size heater you want. You know that 1 gallon of kerosene makes 128,000 btus. Therefore a 10,000 BTU heater burns aprox 1 gallon in 12 -14 hours . And my house needs about 20,000 btus per hr , per 1000 ft. Based on usage. Thats about 6-8 gals a day. Something like this exist for coal stoves. And if so Im wondering why I keep reading about people having cold or hot houses. Quite honestly I was thinking of putting a coal stove in my basement for over a year, but never thought to add the 1000 extra ft of space when making some type of estimate.

 
User avatar
DOUG
Member
Posts: 904
Joined: Wed. Jul. 09, 2008 8:49 pm
Location: PITTSBURGH, PENNSYLVANIA

Post by DOUG » Thu. Dec. 24, 2009 3:07 am

Hi, here are a few posts that will help to get you into a ballpark figure. Read through them, they have some really neat calculations.
Stove BTU Output Based on Temp and Surface Area?
FUEL Heating COST Comparison From Penn State
Calculations for Sizing a Furnace
Thoughts/Questions on Stove Efficiency

 
User avatar
lowfog01
Member
Posts: 3889
Joined: Sat. Dec. 20, 2008 8:33 am
Location: Springfield, VA
Hand Fed Coal Stove: Mark II & Mark I
Coal Size/Type: nut/pea

Post by lowfog01 » Thu. Dec. 24, 2009 3:21 am

Diesel wrote:And if so Im wondering why I keep reading about people having cold or hot houses. Quite honestly I was thinking of putting a coal stove in my basement for over a year, but never thought to add the 1000 extra ft of space when making some type of estimate.
I'm not sure if such a formula exists or not. The reason you read about people having cold or hot houses with hand fired stoves is not necessarily because they have the wrong size stove for their square footage but rather is often due to the floor plan of the house and/or the ability to distribute of the heat. A hand fired stove is a radiant heater and will be hottest in the immediate area of the stove. It gets cooler as you move away from the stove. For instance, the room I have my stove is 75 to 80 degrees or less during the day but my upstairs bedrooms are 65 to 70. That's because during the day or times when people are using the family room I have to run the stove cooler or we get driven out of there. At night I run the stove hotter so that the family room is 85 or 87 because I need the heat in my bedrooms and no one is in the family room anyway. That's why you read about people having hot or cold houses - it's the nature of a hand fired stove. Some folks have better distribution of the heat then others by connecting to the vent system or cutting vents between floors but most of us hand fed people don't. We just depend on the radiant heat and live with a gradual cooling of the house as you move away from the stove.

Actually, I think floor plan is a more important factor in chosing a hand fired stove then the total BTUs. My Mark II has more then enough BTUs for my square footage but getting that heat out evenly to all the rooms is another story. I would have been better looking at the Mark I and getting a second stove for my upstairs arriving at the same BTUs but getting a better distribution of heat. Oh well, if only I knew then what I know now. Merry Christmas, Lisa


 
User avatar
SMITTY
Member
Posts: 12496
Joined: Sun. Dec. 11, 2005 12:43 pm
Location: West-Central Mass
Stoker Coal Boiler: EFM 520 Highboy
Coal Size/Type: Rice / Blaschak anthracite
Other Heating: Oil fired Burnham boiler

Post by SMITTY » Thu. Dec. 24, 2009 6:35 am

Just to add to that ..... if you have a house like mine, where the shades move around when it's windy out, that will cool rooms off also.

When I bought my stove, & just went with what I could afford ..... no formula here! :lol: I learned by trial & error that the Mark I was too small for my drafty house. After 3 seasons, I sold it for $100 less than I had paid, & bought a Mark III. I would have had an SF250 down there, but Harman was overloaded during the STOVE CRAZE OF '08!

I think the basement is the best place for a stove. The heat has nowhere to go but up, keeps your basement dry, plus your floors are warm .... it's a win win. 8-)

 
franco b
Site Moderator
Posts: 11416
Joined: Wed. Nov. 05, 2008 5:11 pm
Location: Kent CT
Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea

Post by franco b » Thu. Dec. 24, 2009 4:39 pm

Diesel wrote:i was thinking of putting a coal stove in my basement for over a year, but never thought to add the 1000 extra ft of space when making some type of estimate.
The type of basement, whether insulated or not can make a big difference too. As Smitty found you need a much larger stove. No Franco Belge or Surdiac. As Lisa pointed out heat distribution can be more of a problem also.

 
Diesel
Member
Posts: 38
Joined: Tue. Nov. 17, 2009 8:19 pm

Post by Diesel » Thu. Dec. 24, 2009 5:13 pm

Ok , a couple things. My Surdiac is described as a Convection coal stove. Not Radiant. If that means they put a sheetmetal casing around it to force the hot air up through it. So be it. Kero heaters come both ways too. And as far as a basement heater and heating the floors. I don't believe it works for everyone. Im pretty sure it wont work for me. The heat wont transfer through the floors. I see the problem is the same for stokers too. A guy buys a 90,000 BTU stoker and puts it in his basement and it wont cut it. And I cant get the heat up two flights of stairs. Im back to peoples posts and what stoves they say they have. And 90,000 btus in a basement and 2000 ft of space isnt working for a lot of people. Ive had to put kero heaters on every floor and that works ok. About 20,000 on a floor and basement. My forced air NG is 84,000 btus. Im guessing coal 40,000 btus in the basement and another 80,000 on the first floor could keep me warm in the worst winter , but run me out of the first floor if I try and keep the upstairs warm too. Maybe two 40,000 BTU stoves might be ok too. As Lisa stated. Ive come to the same conclusion. One stove isnt getting it. Id love to have a BTU formula like kero and figure calculatioons per 1000 ft.


 
User avatar
WNY
Member
Posts: 6307
Joined: Mon. Nov. 14, 2005 8:40 am
Location: Cuba, NY
Hot Air Coal Stoker Stove: Keystoker 90K, Leisure Line Hyfire I
Coal Size/Type: Rice
Contact:

Post by WNY » Thu. Dec. 24, 2009 5:22 pm

yes, location and type of stove is key for heating. You said it, a 90K in the basement may not work for most people.

Many people try and make Stoves into furnaces which they are not. They have smaller blowers, and less BTU output. Most stoves are made to be used in your living area(s), since they have a lot of radiant heat.

Our Keystoker 90K worked great in our other house (1600 sq. ft), it was on the first floor and kept the house comfortable, with a few vents going upstairs. It was in the center of the house. However, When we moved to our current 100+ year old victorian. I tried my Keystoker in the basement with an 8" duct upstairs, didn't work, it was cranking all the time just maintain about 62-65 (as long as the outside temps weren't below about 20, then forget it :( ). Now with the HyFire I with a heat jacket and dual blowers, it works quite well for the front of the house and all of the first floor, the keystoker is in the attached garage and piped upstairs, works pretty good!!

Next project will be a boiler for the whole house, I have learned a lot of what works the best in this house. We keep some doors closed upstairs and the rooms get pretty cool with no heat.

SO, it sometimes is a learning experience and each house is unique in its heating requirements. What works for one, may not for another.

 
User avatar
LsFarm
Member
Posts: 7383
Joined: Sun. Nov. 20, 2005 8:02 pm
Location: Michigan
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

Post by LsFarm » Thu. Dec. 24, 2009 5:28 pm

A stove is meant to be a suplemental heater, not to replace the boiler/furnace in a house.

BUT, many people do heat their homes with just a stove, others have to be real creative with ducting, fans etc to move the heat around.

A furnace that is 80K BTU is reheating once heated air in the cold air returns, and not heating the basement very much, certainly not the exterior basement walls. You can get by with a lot lower BTU capacity if it is ducted, and circulated properly.

Example: member coalkirk heats a 4000 sqft house with a 95K BTU boiler.. but he is doing everything right. Many people can't heat a 2500sqft house with 180Kbtu boiler, because of the many compromises in the instalation of the heating system..

So, there really isn't anyway to size a stove per square foot.. each square foot is different.. mine in my old house probably required 3x the heat that each square foot in my rebuilt 'new' house will require.. it's all in the delivery, insulation, efficiency of install etc.

If you have ductwork in your house, I'd recommend trying one of the coal furnaces, or a small boiler with a water-to-air heat exchanger.

Greg L.

 
franco b
Site Moderator
Posts: 11416
Joined: Wed. Nov. 05, 2008 5:11 pm
Location: Kent CT
Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea

Post by franco b » Thu. Dec. 24, 2009 5:56 pm

You already have a figure from your kerosene stoves only knock about 1/3 off their rated output as they are over rated just as coal stoves are. I say that because in the tests in 1982 by Consumer Reports that is what they found. For instance the Kero Sun Omni 105 was rated for 19,500 yet delivered only 12,000 BTU.

If you will cut the rated output in half for a coal stove you will have a more practical figure. Doug was kind enough to post the BTU figures for a square foot of steel heating surface. At a temperature of 400 degrees the output was about half that of 600 degrees. So by simply running the stoves at very high temperatures the manufacturers can claim inflated outputs. My Franco Belge is rated at 48,000 Btu, but the more practical figure considering burn times is more like 20,000 BTU and 40 pounds of coal burned per day.

Why don't you consider a coal fired furnace tied into your existing duct work? You already have the distribution system.

Richard

 
User avatar
VigIIPeaBurner
Member
Posts: 2579
Joined: Fri. Jan. 11, 2008 10:49 am
Location: Pequest River Valley, Warren Co NJ
Hot Air Coal Stoker Furnace: Keystoker Koker(down)
Hand Fed Coal Stove: Vermont Casting Vigilant II 2310
Other Heating: #2 Oil Furnace

Post by VigIIPeaBurner » Thu. Dec. 24, 2009 11:33 pm

Are you looking for a formula for hour much heat per pound of anthracite is available? I've seen it posted somewhere on this forum at about 13,500 btu/Lb. I used it to estimate how far I push my stove. It's rated at 50,000 BTU/Hr with a top operating temp of 700*. I've found that I go thru about 80 - 90 lbs/day in the really cold weather while maintaining a stove top temp as consistently near the 700* max as I can. It works out this way:
  • 90 lb x 13,500 BTU/Lb= 1,250,000 BTU / 24hrs = 50,625 BTU/hr.
  • Using ~ 80 - 90 Lbs/day is about right for my Vigilant rated at 50,000 BTU/hr.

Post Reply

Return to “Hand Fired Coal Stoves & Furnaces Using Anthracite”