🚀 go-pugleaf

"Some Guy" <Some@Guy.com> wrote in message
news:42BEF3E8.85790470@Guy.com...
> Dll wrote:
>
> > The readout doesn't mean anything.  I'd bet you're getting
2 C
> > max accuracy.
>
> I'm satisfied that when I bring that particular unit (with
it's
> internal and external transducer) along with several other
(different)
> units together in the same place, and see them display a
temperature
> within 1 degree (F) of each other, that there's little
chance that
> they're all out of whack by the same amount.
>
> > Pretty scientific test you had going there...not!
>
> My hypothesis was that spraying water on the roof would
cause a
> decrease in attic air temperature.
>
> My temp display before applying the spray was showing 120+
degrees
> (f).  Within 1/2 hour of applying the spray the temp went to
100
> degrees and leveled off to about 98 degrees after an hour.


 no suprise...sure water cooling works...did you say that was
on an 85F day?     so you cooled the roof to within 15
degrees.    Venting with enough air would have taken the attic
temp closer to the air temp that was used for venting.  as a
wild guess your load vs the cfm....90 deg F. maybe 98 or even
warmer...depends on how big fan is and type of roof
construction.

again. its the temp inside the first 1/2 inch of attic
insulation thats most relevant.

You have 'what works' confused with whats practical.

Phil Scott


>
> This was scientific in that
>
> - I had reasonable confidence in my measurement device
> - I varied only 1 parameter during the study
> - there were no other variables that could have affected the
>   results (like a change in outside temp, cloud cover, etc)
>
> During the entire time the roof-mounted exhaust fan was
running.
>
> > > This is with an attic fan going.
> >
> > Vent fans are tried and true energy savers.
>
> I don't know what the temp would have been without the spray
and
> without the fan running, but I agree that a vent fan
(combined with
> proper soffit ventilation) is absolutely necessary to
prolong shingle
> life and reduce the heat load to the house.