permaculture

[Vint Lawrence <vlawrence@nets.com>]

Laurence,
This is generally a good practice as there can be a net loss on heating 
with a fireplace or stove that is using inside air for combustion, 
especially as the fire burns down. The strategy is most effective if you 
have a way to close off the open fireplace when necessary.
Design considerations include putting some sort of control or damper on 
the inlet air source so that it can be shut off when there is no fire, 
and protecting it from "infiltration" and or occupation by rodents. 
Ideally, ducting should be fire and/or melt proof (i.e.-ceramic or 
metal) near the stove itself.
The only counter indication that I can think of at the moment is if your 
house is already pretty "airtight" you wouldn't be encouraging a 
sufficient airchange rate and would have no indication that your air 
quality was deteriorating (i.e.- backdrafting in the stove). For most 
houses, this is not a problem and would probably be helped by having an 
external source of combustion air when needed.

There have been various studies of this through the years, notably in 
Canada and, I believe ATTRA in the US. There were also studies done @ 
the East-West Center at the University of Hawaii in the 70's or 80's on 
the impact of woodsmoke on respiratory health in developing countries. I 
don't have the citations at hand, but could probably dig them up if you 
have a genuine "need to know".

Otherwise, go for it.

Vint Lawrence
Santa Fe, NM

Laurence Gaffney wrote:

> Does anyone have any advice/opinions on a proposal to reticulate air from 
> outside a house to the air intake of a wood fired stove to prevent extraction 
> of inside air.
> Can/Does this work? How do we know so?
> What are the Advantages &/or /Disadvantages?
> Any Specific Design advice?
>
> Laurence Gaffney
> Australia
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