Using wood stove as a secondary source

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Duramaximos

Member
Dec 18, 2011
31
Alberta, Canada
Hello,

I'm nearly ready to start using my new Oslo stove and have some questions.
The stove will be providing secondary heat along with my exisiting natural gas furnace. I'm curious to know how to set my furnace to work in conjunction with the stove. I mean, should I keep the thermostat at the usual setting or lower it some?

Also, will the furnace fan cause me some problems resulting from pressuization or de-pressurization of the house? I don't know if I need to go to the extreme of turning my furnace off when I'm burning the stove. I also think it might be nice to turn the furnace fan on from time to time to circulate the air in the house.

Any suggestions or tips would be great.
Thank you!
 

Pagey

Minister of Fire
Nov 2, 2008
2,435
Middle TN
We set our electric heat pumps to come on at 69F upstairs and 65F downstairs. The house will usually hold the heat from the Endeavor until about 1-2am, depending on how cold it gets on a given night. Apparently though we're in the relatively mild Southeast, our house bleeds BTUs...but that's another story and another thread/forum.

I've tried the "fan only" as a means of cicrulating heat, and it was, in two words, epic fail. You may have better luck, but I found that by the time any heated air made its journey through the ductwork, it was no longer heated, basically. Just a waste of electricity, really. I've had far, far greater results with the stove blower/ceiling fan combo. Also, as 99% of the members here will attest to, a small fan at floor level blowing cold air TOWARD the stove will set up a natrual convection loop, replacing the cold, heavy air with warm, lighter air.

Finally, I've never had an issue with the cold air return competing with any combustion air for the stove.
 

Wood Duck

Minister of Fire
Feb 26, 2009
4,790
Central PA
I set my electric baseboard heat at the setting I want the room to be and then the stove simply reduces the amount of time the electric heat kicks on. At least that is how it would work if my thermostats were working right.
 

jjs777_fzr

Feeling the Heat
I lowered all my zones when I started burning wood.
Although you really don't have to touch the stats - I did only because it sort of makes me get the wood fire going more often rather than take the lazy approach.
 

pen

There are some who call me...mod.
Staff member
Aug 2, 2007
7,957
N.E. Penna
Are you comfortable w/ your home being warmer than where your thermostats are currently set? Or would you like to keep things pretty close to what the gas furnace keeps things?

pen
 

begreen

Mooderator
Staff member
Nov 18, 2005
85,900
South Puget Sound, WA
Our thermostat is a digital setback unit. It's set for 69 day and 63 night. When the stove is going 24/7 the heat pump very rarely comes on unless the stove goes stone cold.

Your heating system shouldn't compete much with the stove unless this is a super-tight house. I would just leave it at its normal setting and see how it does.
 

LLigetfa

Minister of Fire
Nov 9, 2008
7,360
NW Ontario
My primary heat source is a FA gas furnace. The smart thermostat stays set the same regardless with setbacks at night and during away settings. My objective is to keep the house a little warmer with wood heat so that the furnace doesn't run while we are home and awake.

As long as the stove was installed to code and is not within 10 feet of a cold return, not connected to your gas furnace ducting, and not in a small closed room, the operation of the stove and furnace at the same time would not be an issue.

My furnace comes on every morning before I wake. The wood stove helps to warm the house and augments the gas furnace. After the smart thermostat goes into "away" setback mode, the wood heat has increased enough to keep the furnace from running until the next morning. I need the furnace to run for a while to humidify the home.
 

Duramaximos

Member
Dec 18, 2011
31
Alberta, Canada
pen said:
Are you comfortable w/ your home being warmer than where your thermostats are currently set? Or would you like to keep things pretty close to what the gas furnace keeps things?

pen
I think the house is comfortable where we have it set. On colder days, although the termostats read the same temp, I can feel a chill radiating from the outside walls. Elliminating the chill and working the furnace less would be perfect.

We are having an unusually mild winder. I'm use to seeing temps between -15C and -30C this time of year, but we have been hovering around the freezing mark for the last month. The house is 6 years old and has very good insullation and vapor barrier.
 

Duramaximos

Member
Dec 18, 2011
31
Alberta, Canada
LLigetfa said:
My primary heat source is a FA gas furnace. The smart thermostat stays set the same regardless with setbacks at night and during away settings. My objective is to keep the house a little warmer with wood heat so that the furnace doesn't run while we are home and awake.

As long as the stove was installed to code and is not within 10 feet of a cold return, not connected to your gas furnace ducting, and not in a small closed room, the operation of the stove and furnace at the same time would not be an issue.

My furnace comes on every morning before I wake. The wood stove helps to warm the house and augments the gas furnace. After the smart thermostat goes into "away" setback mode, the wood heat has increased enough to keep the furnace from running until the next morning. I need the furnace to run for a while to humidify the home.
Interesting. Why is having the stove close to a return air duct a bad thing? I assumed moving the warm stove air around the house would be good.

Currently, the furnace thermostat is located in the large living area on the main floor. It is approx 20 feet from the wood stove. My only concern is the stove will warm up the main room, thus causing the thermostat not to engage the furnace leaving the upstairs bedrooms relatively cool.
 

begreen

Mooderator
Staff member
Nov 18, 2005
85,900
South Puget Sound, WA
I suspect it has to do with the potential of spreading fumes and CO rapidly to other rooms of the house, and/or the potential of rapidly spreading a fire.

If you find that the upstairs rooms still need heat a simple fan may help stimulate convection to them. Or you may want to put the upstairs on its own zone and thermostat. Try it for this season and see how things work out. The heat in some houses balance out pretty nicely without assistance.
 

pen

There are some who call me...mod.
Staff member
Aug 2, 2007
7,957
N.E. Penna
Duramaximos said:
Currently, the furnace thermostat is located in the large living area on the main floor. It is approx 20 feet from the wood stove. My only concern is the stove will warm up the main room, thus causing the thermostat not to engage the furnace leaving the upstairs bedrooms relatively cool.
That's a real concern. Considering that possibility, I'd leave the thermostat set right where it is for the time being. You can always adjust it as needed even w/ the furnace burning.

What will determine your comfort level will be how well the heat can leave that stove room and travel to the upper levels.

pen
 

LLigetfa

Minister of Fire
Nov 9, 2008
7,360
NW Ontario
BeGreen said:
I suspect it has to do with the potential of spreading fumes and CO rapidly to other rooms of the house, and/or the potential of rapidly spreading a fire...
+1
A cold return on a FA furnace can create a zone of depression that could close-couple to the stove. The drop in pressure could cause CO to be drawn from the stove/smokepipe. Code requires that there be at least 10 feet of separation. In the case of a small room that has the potential to be closed off, the sq in of cold return needs to be balanced by the sq in of supply air so as not to the lower the pressure in the room. The AHJ should address those when the permit is pulled or when the install is inspected.
 

leeave96

Minister of Fire
Apr 22, 2010
1,113
Western VA
My vote is to use your stove full time and turn the furnance completely off!!! :coolsmile:

Great stove you got - how about some pics!

Happy burning,
Bill
 

firefighterjake

Minister of Fire
Jul 22, 2008
19,298
Unity/Bangor, Maine
Random thoughts . . .

I set my oil boiler thermostats to kick on the boiler at 60 degrees F . . . but that's because my wood stove is my primary heater and the oil boiler is just there for when I'm away from the house for too long, when I don't wake up early enough in the morning or when it's wicked cold outside during a long night.

Secondary heat huh . . . you may be like many of us . . . I figured I would just use the woodstove during evenings and weekends to help reduce the cost of heating oil . . . I think it took me two or three weeks and I was committed to burning wood 24/7. It can be addictive . . . and it just isn't the money savings that keeps me burning wood.
 

Larry in OK

Member
Oct 31, 2011
112
NE Oklahoma
I had some of the same concerns when I installed my stove in November.
I set the thermostat on my central heat unit to 60 °F figuring that wouldn't be too uncomfortable a temp if the house got cold before I could get another fire built up. So far that plan has worked pretty good as my furnace hasn't kicked on since the 2nd day I was burning wood.
 

tcassavaugh

Minister of Fire
Jan 10, 2010
1,047
Southern Maryland
i set mine back to around 60 degrees. i have a ranch and the bedrooms are back in one end....away from the stove, but stay pretty warm anyway as long as the doors are open. i don't want the furnace to come on unless it gets cold in the house. the Jotul keeps the upstairs warm. downstairs in the basement stays around 60 so far, cause i havent started the summit, so its not a real factor except where there are bare floors (kitchen and baths) they get a little chilly....
turn it down and throw on an extra blanket.

cass
 

fredarm

Minister of Fire
Aug 28, 2008
585
Eastern Mass
I set the thermostats on my oil-fired hot water baseboard heat (a New England specialty--never heard of it growing up in Michigan) to 66 during the day and 62 at night. The downstairs thermostat is in a different room than the stove, so if I set it any higher the heat would kick on too soon and make the living room (where the stove is) too hot.
 
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