Ducted slow combustion: possible ?

Cabinfever · Apr 06, 2007 1:35 pm

I'm planning a large two-storey house in Tasmania and really like the idea of a slow combustion wood heating system.

It'll be possible to place the unit in the middle of the bottom floor near the stairwell. But that's not realistically going to be able to heat the whole house is it ?

So is it possible to get heat from a combustion unit ducted to upstairs bedrooms ? (I think this may be a really stupid question....)

Is all this just loads of trouble and I'd be better off with a standard ducted aircon/heatpump system ? That way maybe I'd keep a small combustion unit downstairs just for the cosiness...

I'm looking for something with the cheapest possible running costs. (The house will also be very well insulated).

mattwalker · Apr 11, 2007 9:28 pm

Hi Cabinfever,

This is possible. I worked with Coonara woodheaters 10 years ago and we were selling them then. They used to duct using 2 x lengths of 3 metre long 6" ducting and stick a fan in the middle, attach it to a wall switch and...

Wah Lah - Ducted Slow combustion heating.

There were also rear ducting kits available too. I am sure you could still get these today.

Matt

Cabinfever · Apr 11, 2007 11:12 pm

Thanks Matt.

I really like the idea of slow combustion, and that it requires a bit of effort. But maybe the novelty would quickly wear off ?

All the Europeans seem to go for underfloor heating. All that tubing under the floor though ? Seems like a malfunction waiting to happen...

mattwalker · Apr 11, 2007 11:31 pm

Another good way of distributing heat from a central area is to use a ceiling fan in reverse. ie have the fan pushing the hot air away from the ceiling and into the surrounding area's.

My folks used this method when we were kids and it worked really well.

Matt

Yak_Chat · Apr 17, 2007 9:54 pm

Great idea and it works well. If you can lock the room off that the heat in that areas stays warm and an hour or so before you go to bed, turn on the fan and move some of the warm air to bedrooms or other areas to take the chill off it. Also make sure the pipe work is insulated / wrapped in insulation or a lot of the heat will be lost on it's way.
Go for it and use that heat elsewhere.
You'll find that once winter starts the fire never goes out till spirng, and moving the hot air around helps heaps.
Steve

3timesbuilda · Apr 19, 2007 12:07 pm

Hi Cabinfever,

We are having ducted gas as part of what the builder puts in. That gives us 8 outlets including one in each bedroom upstairs.

Once the house is completed, I want to install a slow combustion wood fire downstairs in the center of the house. My idea is that we will run the fire most of the time and have the ducted gas for really cold nights. The heat from the fire should radiate outwards and warm air should rise heating the whole house (at least that is the theory).

My main issue is running the chimney pipe upstairs - having a big hot metal pipe comming through the floor and looking like a pillar is not really what I had in mind. 2 options I am considering are; run it through a cupboard and hide it with paneling or put in a second fire upstairs (directly above the ground floor one) and use a single chimney pipe for both. What do you think would be best?

At the moment, we are getting a good supply of wood from the trees that we unfortunately had to remove to build the house. Next job will be to split it and stack it. Free heating (apart from all the work that goes into preparing and maintaining it) gotta love it.

3xb

Cabinfever · Apr 19, 2007 1:29 pm

Hi 3times,

The choices for heating are very interesting. If you start with good insulation and double-glazed windows as a given then the options really spread out. Unfortunately gas isn't really widely available here, but ducted aircon & wood are obvious choices.

http://www.greenhouse.gov.au/yourhome/t ... l/fs44.htm
Has good info.

Even more interesting I think is that wood burning is considered the 'most green' and friendly heating method and the cheapest:
http://www.choice.com.au/viewArticle.as ... ng+options

In the future who knows how expensive electricity may become ? Wood (or gas) may then seem even more attractive. And of course if there's a power failure you won't freeze !

I know what you mean about the chimney running upstairs. Since my wood burner would be roughly in the middle of the house (near the stairwell), I was thinking that where the chimney comes out upstairs could be somehow 'exposed' with little radiant 'heat distributors' of some sort. Exactly what they'd be I've no idea !

mattwalker · Apr 19, 2007 5:10 pm

Hey Cabinfever,

From the top of the heater to the ceiling there is a 6" inner flue and an 8" flue (usually decorative) cover. There is a thing called a ceiling ring which these both pass through into the ceiling or in your case the next level of the house.

The next level could be ceiling ring on the floor with 8" decorative cover to the ceiling with another ceiling ring.

This would give you so ambient heat for upstairs and the best clothesline in the southern hemisphere!! :lol:

Matt

Cabinfever · Apr 19, 2007 5:31 pm

A wonderfully simple idea - I love it ! But do you think the 8" flue on the second level would radiate substantial heat ? I'm imagining a situation upstairs where everyone is huddled around the flue like tramps around a fire in a 44-gallon drum :shock:

mattwalker · Apr 19, 2007 6:09 pm

Hey cabin fever,

It works reasonably well yes! It all depends on the fire downstairs. If its a "rager" then it works well, on a slow overnight burn not so much. It would help take the chill off the air most days though.

Matt

Yak_Chat · Apr 19, 2007 7:47 pm

My house a similar setup. Wood fire downstairs, pipe through the ceiling, and up through the next level, (which was a 20 year later extension) but they have not sheilded it at all and there is a plastic blob melted to the flue, so obviously something has been hung to close at some stage.
I'm yet to spend a winter in this house but expect that with a fire going downstairs, even on slow burn, the heat from downstairs will also travel upstairs via the stairwell, so it should be bearable.
Winter will tell.

I also have seen a architect designed enviro house where the wood fire heat buildup was stored in a triangular ceiling pocket, and at night the owners popped on a fan which moved the trapped air via a duct to the bedrooms to take the chill off them before they went to bed.
I've lived with woodfires for many years now and if you get them going and insulate the house well, ie draft protectors around the door jams, ceiling insulated etc, it's nice to come home to warm fire that never goes out - and if managed properly the house stays around the 15 to 22 mark all winter.
SJ