Wood stove and central heating

We have a home with central heat and are wanting to get a wood stove.  We were hoping to get rid of the central heat and only have the wood stove.  I was thinking it would be great if I could use some of the heat from the pipe to push through the existing duct work in to the rooms farthest from the stove.  I figure I'd have a short section of single wall in the attic.  The duct work would somehow attach to this and the heat would be pushed through the duct work in to the rooms.

Does anyone have any experience with this?  Would this even be possible?

Hi Jess. Not specifically. A number of years ago we had a wood heater in the basement and added vents to the rooms above in hopes of getting some heat up there, but it didn't work. And we didn't try ductwork.

Some questions about your idea would be: How far do you want to push the heat? Will you do it with a fan?

Something my husband and I found really helpful is an Ecofan.



We have two, one for the woodstove in the front room, and one for the cookstove in the kitchen.



They are thermoelectric, i.e. work off the temperature differential between the blades and the base of the fan. They work very well.

Do you have ceiling fans? We found they helped push heat to other parts of the house as well.

Otherwise, experiment with your idea and let us know how it works out!

Hi Jess;   Even if you successfully get wood heat in your home, I would simply turn off your central heat and leave it in place. Absolutely nothing is warmer than wood heat its the best! However if you want / have to leave home in the winter. It sure is nice to be able to do so without getting a house sitter.

As far as your idea. Moving warm air is harder than it seems. Air cools quickly moving thru uninsulated ducts. Even an insulated duct will steal heat to stay warm.
Tell us the design / shape of your home. How large is it? One story or several? How many rooms?  What kind of chimney if any is in it?
Were you thinking a standard box stove ? The creosote generating kind?
Or were you hoping to build  a super efficient  rocket mass heater?  Much better idea in my humble opinion...

You might be interested in one of Matt Walkers stove plans.  Matt builds super efficient riserless RMH stoves of many different sizes and shapes.
He then sells detailed plans of his designs that you or a builder can assemble on site.  His plans include complete consultation before /during and after a build!
Here is a link to his website http://walkerstoves.com/index.html

If you like the central heat, is there something preventing you from getting a wood furnace instead?

We heat with wood but use the central oil heating system rarely. Specifically, we use it for 10 minutes on cool days in the spring and fall, when lighting a fire would be a very bad idea but we feel cold. Sometimes we use it first thing in the morning when it has been particularly cold and the banked fire didn’t keep us warm enough overnight. Sometimes I wake up in the middle of the night and put on more wood, so it’s still warm even in below-zero (F.) weather.

The best use, though, is what Thomas said - preventing the house from freezing when we go away for a weekend or longer!

Our house is super-insulated so it doesn’t take much to take off the chill. A stove that still has hot coals in the morning is ideal, especially for restarting the fire in the morning.

We use wood heat but still have our central heating, like the others have said. We have it set at a very low temp to come on. It didn't come on at all last winter but it's nice to know that if it reached the point where the water would freeze we have a heater that will kick on and prevent it.

We just leave doors open and have the fan on top of our wood stove. We do have to add additional heat in the form of electric oil heaters to our master bathroom and my sons room. Both of those have walls blocking them. Sons room is only heated at night. We have timers on them so they're not on all the time.

I'm working on a plan to put a RMH in a brick bell near my furnace in the basement. I want to skin the bell with those hollow bricks aligned vertically with air inlet at the bottom. The idea being, the stove will heat the bell walls and hollow brick outer skin and cause convection in the air channels, making cold basement air warm and rise through them. Then on top of the bell I want to figure out how to funnel this warmed air into one duct heading up into the house (this one duct that I would disconnect from the furnace for use with the RMH instead.) I'm still working out how to create this insulated funnel cap for the top of the bell. Still trying to figure out a lot really, just sharing the concept.  

The idea being supplementary heat. The furnace is doing it's own thing, kicking on and off via thermostat. But any time I do a burn that's less work for the furnace. If I'm real lucky, very little electricity for heat used because I'm on a co-op and power is expensive!  

In the past, I used the "fan only" setting on a forced air furnace to help circulate the heat from a wood stove through the house. It's not perfect, but it helps. If the option is not present, a switch can easily be added. Yes, it uses some electricity, but the footprint is still smaller than burning oil or natural gas.

Hi Matt,   There are some details left out of your description that would be very helpful.

1) Were you thinking of a J tube rmh or a batch box?
2) What size of a system 6" or 8" ?
3) Do you have an existing chimney close by to tie into?

A rocket mass heater is generally put in a space of your home where you frequent often. Do you spend much time down in your basement?
The main reason being is that it does require tending often (in particular to a J tube style). Also, one of the great parts of owning a rmh is the ability to enjoy the conductive heat that it gives off through a bench or thermal mass of some sort.

Also, some people have experienced problems with drafting when they put their stove downstairs. As long as you have a good drafting chimney however, this should overcome the house itself acting as a chimney and competing for dominance. Certainly not a show stopper, but something to consider.

If you could also provide a picture of your idea, that would be helpful as well.  

Gerry Parent wrote:Hi Matt,   There are some details left out of your description that would be very helpful.

1) Were you thinking of a J tube rmh or a batch box?
2) What size of a system 6" or 8" ?
3) Do you have an existing chimney close by to tie into?

Gerry, I was intentionally vague since I don't have this totally fleshed out yet. Rather just providing an example of a concept using existing house ducting as the original poster mentioned.
But since you asked :)
Batch box, 7 inch DSR2, existing brick chimney that goes to the basement floor. Choosing the basement because I do spend time there (bedroom even), easy to get messy wood in the walkout, and I don't trust as much mass as I want on the main floor.
Early days on this plan but as I develop it further I do intend to share the results of this scheme to pump heat up with no moving parts. Right now I'm focused on fully testing the core in my shop to give me (but mostly my wife) peace of mind that it's safe to move indoors. My ceramic fiber board arrives today, woot woot!  

Sounds like your moving in the right direction Matt. Testing it out is a very wise idea to get you closer to what your looking for before committing to an indoor build.
Awesome that your cf board arrived. Like Christmas come early to a rocket scientist!

Jess, one option may be an "add on wood furnace".  They tie into the existing ducting so that you can use wood or the central furnace to heat your house.  Here's the first one that came up when I searched for it:
Shelter 150,000 BTU add on furnace

One comment is that you may want to consider an alternative source of heat for when you are away or ill. My childhood home was heated by wood stoves, to go away for more than a day or two and avoid frozen pipes, we also had electric baseboard heat. Now, when my dad is ill or injures himself, he also uses the electric heaf until he is well enough to carry in wood again.

Another house i lived in just had an outdoor wood furnace, which was much more even heat though it used more wood than the woodstoves. However, there was no electric heat, so it was difficult to leave the house for any time in the winter (we set up portable heaters)

My uncle has a propane furnace, but radically reduced his heating season with a simple well placed woodstove in the basement. The propane furnace kicks in on days the woodstove isnt sufficient, and, again, he can go away in the winter without fearing the pipes will freeze.

I agree: using "grid heat" as a robust backup is practical and reasonable. In cold winter climates, sometimes, there is no other good option. The trick is to grab every off-grid BTU you can.

I have tried using the fan on our central heating unit to move the heat from the wood stove around the house, but it is extremely high in electrical usage for how inefficient it is. It's much better for us to turn on the central heater for 10 minutes than relying on the wood stove to take the chill off. But our climate is fairly mild and the wood stove is overkill. We have to open windows when we use it. The catalytic converter on the wood stove has the same issue, not a good use of power.

I have been considering installing transoms above our interior doors to help facilitate warm air movement. Has anyone tried this?

Through no effort on our part, our house has electric, gas, and wood heat.  In one crisis or another I have used all three ...not at the same time. I am a huge believer in reduncy, so I take some comfort in having multiple systems backing one another up.

I have a stove but don't know exactly what it is , date on top of stove is 1805, anyone know what this is , and can someone tell me how to post pictures

Hi Dan,  Big welcome to Permies!

Sorry I can't help you with your stove.

Here is a very basic way to include pictures... If you need more help, please ask.

To post a picture from your computer:
1) After hitting the reply button, below the text entry box click on the Attachments tab.
2) Click "upload a file"

To post a picture from a website:
1) Click the "Img" button along the top row of buttons
2) Enter the web address of the photo you want to include