[Strawbale] Comment on forced air systems and dust

[Speireag Alden]

On 2008, Jan 02, at 10:36, dfugler at cmhc-schl.gc.ca wrote:

> Hydronically heated houses are just as "dusty" as forced air houses.
> Forced air systems do not produce dust; if anything, the filters  
> harvests
> some of the airborne particles compared to houses without moving  
> air. The
> implications by some people on this listserve that hydronically heated
> houses are cleaner has no proof and, in theory, should not be true.  
> Dust
> or airborne particles come largely from the outside air and then from
> indoor activities (cooking, smoking, resuspension of floor dust, etc.)
> None of these "dust" sources are due to the heating system, be it  
> forced
> air or hydronic.
>
> Different houses will be "cleaner" or have fewer particles than  
> others,
> but the method of space heating is not a big factor in the  
> cleanliness of
> the house.
>
> OK. I'll stop talking now...

     No, don't stop talking.  We have a lot to learn from you.

     I agree that, obviously, forced air systems do not produce dust,  
and that the filters should remove some (but only if they're used  
properly, which in my experience filters of every kind generally  
aren't, even by people who should know better).

     However, in my limited anecdotal experience, I think it's fair  
to say that forced-air systems stir up existing dust more.  That dust  
can lie there and pose no problem, and then become a problem when  
it's stirred.  If the dust is stirred a bit, regularly, then the  
cumulative effect over time might be a bit like the cumulative effect  
of air leakage through a pinhole in the wall, over time:  significant  
higher exposure to airborne particles.

     I freely admit that this is theorizing and hand-waving after  
having spent time in a non-random bunch of houses, most (all?) of  
which weren't of optimal design and maintenance.

     But that describes most houses, after all.

     Do you think it would be fair to say that, in sub-optimal  
conditions, forced-air heat systems tend to keep more dust in  
suspension in the living space air than hydronic systems?

-Speireag.