Woodstove versus wood boiler ROI

[ejb]

Hi guys.

Like everyone else my plan is to use a lot of wood this coming winter to cut down on my fuel bills...and I am trying to decide between going full-speed ahead with a state-of-the-art wood boiler w/1000 gallon heat storage tank from TARM (which is going to cost roughly $16,000) versus a woodstove up in the living area that will likely cost $2000 or so.

Background: I have a house in the cold part of New England where 10-20 below can be common in the winter. My house is about 2800 SF, not an open floor plan, about 40 years old (so not super draft, but not super tight). I currently heat with oil (FHW) and have used an average of 1950 gallons a year of the past 5 years (thats each year!).

All my wood is free and I have a lifetime supply on the property. (and I enjoy processing it).

As far as payback, the tarm is capable of heating the whole house plus DHW 100% wood...the payback, even if oil drops back to $1.50 gallon is about 5 years, at current prices they payback is about 3.5 years...so really a no brainer..

BUT, what I can't seem to figure out (since I've never used a wood stove heavily) is how much of the 2000 gallons of oil per year I could save by using just a wood stove, not to replace the oil, but to supplement it. With my non-open floor plan, and the fact that I have FHW w/radiators that I need to keep from freezing, seems the best I could do with the woodstove is supplement the heat with it.

Anyone here with a similar situation give me some idea how much (a %?) of your heating bill you can knock down with just a wood stove. If it only saves me 10-15% of the oil, the wood boiler seems a better wa to go...on the other hand, if I can 50-60% of my oil costs I think that tips things back to the wood stove over the boiler on a pure ROI basis...

Thanks in advance!

 

[Egon]

without a doubt the wood boiler would be the most thermally efficient for heating your house. The wood stove may interfer with keeping other rooms warm.

Me - I'd go with a wood stove as I like looking at flames. Seems restfull.

Egon

 

[PhilNH5]

ejb,
I heat with two wood stoves with oil fired forced hot wateras a backup. The only reason the wood stoves work for me is because I live in an open concept house.

A woodstove that can heat 2000 sq ft does not do any good if all of the heat is confined to one room. Even with fans and vent holes cut in walls you would have a hard time moving the heat to where you need it to be.

I still burn about 600 to 700 gallons of oil a year. I live in a log cabin and outside air infiltration is terrible. I have always used the woodstoves so I do not know how much oil I would burn if I used oil alone. But I am burning 4 to 5 cords of wood. I read in the paper the other day that on average a cord of wood supplies the heat of 200 gallons of oil.
The boiler would probabaly work better in a conventional house. Either way heating with wqood is a significant time investment. Not counting the fun part (cutting and splitting) I still spend lots of time hauling wood and stoking the stoves all winter.

Phil

 

[dmccarty]

ejb,

I'm not sure I can directly answer your questions but here is what we did, what it cost this past winter, and what we hope will happen this winter.

The new house we built and moved into in Jan of 2005 has some passive solar design. Not as much as I would have liked but as much that would fit the budget and the lot. We put in a colored concrete floor to give us mass and to put in radiant heating in the floor. We had planned to put in solar water heaters on the roof to supply hot water for the heating of the house and hot water usage. The roof pitch was set to get the most sun to maximize hot water generation. We also planned to put in a wood burning stove. Like you we have a lifetime supply of wood and I like processing the firewood even though this year I'm behind in the job...

Then the budget realities hit. Would we rather have a lifetime roof/granite counter tops, better trim, etc or solar heating? /forums/images/graemlins/grin.gif It looked like the the solar water system and radiant pipes in the floor was going to cost use around $7,000 to $9,000. And that would not provide 100% heating of the house.

$7,000 is ALOT of money to heat the house. In January our power bill was $175. Our base power usage without heat/AC is $90 so it cost us $85 to heat the house during the coldest part of the year. We only heat for roughly four months a year so it would take us at least 20 years for the solar to pay itself off. About the time we would have to replace the collectors....

So, no active solar.

We looked at the Tarm boilers as well but the price issues where the same. Thus no Tarm.

This winter we are hoping things will be different. The wood we burned last year had been down for dang near ten years I think. But it was still wet. It kept us warm but not as well as we had hopped. We also had some issues with building the house so part of the windows in two bedrooms had plywood for windows. /forums/images/graemlins/blush.gif /forums/images/graemlins/grin.gif That has been resolved and should keep the rooms warmer this year. And I have nice seasoned wood this year.

SOOOOO, hopefully this year the wood stove will keeps us much warmer than last. We do have an open floor plan which helps. The passive solar does keep the south side of the house 4-5 degrees warmer than the other parts of the house. HOWEVER, if we still feel that we are spending too much money to heat the house or or just not as comfortable as we would like we will put in a second stove on the other end of the house. We thought about putting one in when we built but decided to hold off to see how well the house works. Wood stoves are cheap compared to the Tarm boilers/Active solar.

So if this year is not like we want we will put in another wood stove or maybe a corn stove.

Our house is 2450 square feet with 2x6 walls with an R25. Attice is about R40ish which is high for our area. I'm going to do a bit more insulation this fall. We have been very comfortable in the house during the winter and summer. In our old house we where always chilled and the power bills where the same but heating a 1250 sf house. We are far more comfortable in this house. Not sure how you put a dollar value on comfort.

Later,
Dan

 

[SPIKER]

One thing not mentioned often between wood stoves INSIDE vs OUTSIDE, be it wood boilers or dual fuel units ect. is that AIR has to come into the building to feed the fire & the exhaust the stove/fire place is putting out the roof through the smoke stack of choice. this air needs heated form outside temps to inside temps so in many cases a big ole raging fire in a wood stove/conventional fire place can actually make other rooms not occupied y it colder as the cold air comes in through every crack it can find. so mantaining a good draft in a highly sealed home becomes more of a problem to get / keep a draft for the flue going air needs to come in...

anyhow just a though there are many less expensive units than the tarm units and you can add the extra tank for hot water storage too if you wish and pump out of it. though some areas are now looking at banning the high emmision low fire rate stove/boiler units outside...

Markm

 

[mygoatboy]

Hello,
I think I know exactly what you need. An outdoor wood furnace...

http://www.centralboiler.com/

They cost about $6,000 and up but you they burn green pine and other softwoods. I have one here in Sterling, MA which is North of Worcester. I am good friends with the guy that sells them in Oakham MA. You only load once a day unless it is darn cold and windy and then twice a day. You use your house thermostat so you get nice even heat.

Daniel

 

[Highbeam]

The outside combustion air supply has been deemed a myth or insignificant by the hearth people at woodheat.org. Seems that even a modern house needs some fresh air.

It can't hurt to provide a fresh air supply to an interior stove.

 

[beenthere]

Some rural Townships in Wisconsin where my brother lives are banning the outdoor wood burners, as so many stoke them with 'green' wood that gives off a lot of smoke. The valleys in the mornings have a thick layer of smoke due to the poor burning of the wood.

Wet or green wood will burn, however it can be considered a waist of wood, because considerable wood energy is used to convert the moisture to steam before the rest of the wood can produce energy to heat. Effiecient burning is more easily accomplished by burning dry wood.
But as they say, one 'can' burn green wood. It works, but it doesn't produce much heat per pound harvested, split, and loaded into the burner. Probably twice the volume of green wood is consumed to get the same heat as that volume of wood if air dry.

 

[Deerlope]

I just received some new info on wood burning for heating homes. I do not have a web address but the company is very new. Switzer's Custom Woodburning System, Inc.
1557 Ellis Road
Dundee NY 14837
1-607-243-8689
The reading material that I received is not a sales pitch. I think that this guy is really onto something. Before you buy get some infor from him.

 

[dmccarty]

Highbeam,

I read the reference you mentioned last year and it made me think. We where building the house and we put in a 6inch PVC pipe that goes under our slab from the south side of the house to the hearth that has the wood stove. Origionally I was going to connect the stove to the pipe. But the article and the fact the pieces where not quite fitting togather meant that I left the pipe and stove disconnected.

On our stove the "connection" went to the back of the stove and the air was sucked into the firebox from the bottom of the stove. The connection was not required but an option...

What we ended up doing is leaving the pipe and stove disconnected. When the fire is burning you can put your hand over the air supply pipe and feel the air being sucked into the house. Since the air supply is right behind the stove the cold air is heated and is not noticable unless you put you hand over the pipe. We have a VERY tight house. All but two windows are casements which basically do not leak air. I'm not sure I believe the info in the article is right for every application.

Later,
Dan