[Greenbuilding] New HVAC unit

[Bob Klahn]

Bobbie,

No sleep for me tonight, I see.

I disagree *loudly and strongly* with his statement that cellulose will 
be an allergy problem!!!

You are absolutely right, fiberglass is far worse and more likely to get 
down to the living space because the particles that become airborne are 
a smaller, lighter fiber than cellulose.

Cellulose will settle and form a 'crust', locking in the fibers.  
Fiberglass does not.

You need to deal with several potential leaks that could connect the 
living space and the house.  The ducts, of course, but if the fan, 
housing and other parts are also up there, all cabinet joints, the 
filter access (even if the access door for servicing filters is tight, 
I'd still tape the edges between services (it's the only appropriate 
place for standard 'duct tape'; it will hold the month between servicing 
and it's cheap).

Of course, all of the grill boot penetrations /must/ be sealed to the 
ceiling, as should any bath exhaust fan that is ducted through the attic.

Then, all of the other penetrations mentioned in my first post...

If you have to work in the attic in those temperatures, limit to about 
15 min stints; hydrate religiously and get out if you start to feel 
better - that's an early sign that the heat is getting to you.  Early 
morning is typically coolest, after a full night's chance to cool as 
much as it can.

Haven't mentioned, or seen mention of, ventilation of the attic.  If 
it's not, that might help.  At least it might let you open the access 
and intentionally lose a bit of living h space chill up there, to extend 
your safe working time.

G'night.
Bob Klahn

Good luck.
Bob Klahn


On 6/1/2011 10:12 PM, Bobbi Chukran wrote:
> The HVAC guy said he could do blown in fiberglass of some sort (no 
> formaldehyde, he claims) on the attic floor before they install the 
> ductwork.  When I mentioned cellulose, he didn't seem to like that 
> idea.  He seemed to think that with my allergies, it might be an 
> issue.  I'd certainly rather breathe cellulose than fiberglass.  Of 
> course, if the ducts are sealed as well as they should be, there 
> shouldn't be ANY leakage into the house.  Working up there in loose 
> fiberglass would not be pleasant should we need to do that.
>
> Problem is, it doesn't cool down at night here, or doesn't 
> consistently.  It's 9 pm now, and it's still over 90-degrees.  We are 
> frugal with the AC, but do need it.
>
> I understand about the proper sizing.  Our former house was never 
> comfortable because of that.  We're going to ask the guy if this unit 
> he's recommended can be downsized a bit since we will be adding so 
> much insulation.
>
> bobbi c.
>
>
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