## Re: Indoor Apparent Temperature

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• David, In the files section, check out: Files Weather Algorithms and Formula Indoor Comfort Index.doc
Message 1 of 4 , Jun 8, 2011
David,

In the files section, check out:

Files \ Weather Algorithms and Formula \ Indoor Comfort Index.doc

--- In wuhu_software_group@yahoogroups.com, David Lipper <glenvilleweather@...> wrote:
>
> Hi, Heath, how do you calculate the indoor apparent temperature?
>
> Using version 1,0,216,184, I get (by hovering) IAT=83.3F at IT=84.2F, IH=50.0%. That doesn't seem right.
>
> A calculator at http://www.weatherimages.org/data/heatindex.html shows IAT=85F with the same input values.
>
• Thanks! Hmm, the formula gives a lower number for IAT (Heat Index) than the actual temperature. That seems counter-intuitive. It talks about mean error of
Message 2 of 4 , Jun 8, 2011
Thanks!

Hmm, the formula gives a lower number for IAT (Heat Index) than the actual temperature.
That seems counter-intuitive.  It talks about mean error of .608, and maximum error of 1.98, but dismisses that.
It also refers to numbers in figure 3-1, but the paper is missing that figure.

The tables they do include (5-1) cover only 61 to 75, so perhaps this formula is not appropriate for temperatures above 75.
In fact, the cause given for using this formula was that the conventional (US) heat index is only suitable for 80+F.

On 2011-06-08 17:29, wuhu_software wrote:

David,

In the files section, check out:

Files \ Weather Algorithms and Formula \ Indoor Comfort Index.doc

--- In wuhu_software_group@yahoogroups.com, David Lipper <glenvilleweather@...> wrote:
>
> Hi, Heath, how do you calculate the indoor apparent temperature?
>
> Using version 1,0,216,184, I get (by hovering) IAT=83.3F at IT=84.2F, IH=50.0%. That doesn't seem right.
>
> A calculator at http://www.weatherimages.org/data/heatindex.html shows IAT=85F with the same input values.
>

• I think the 3-1 was a typo and they meant 5-1. I guess the original research by NOAA was lost and they basically used the table to re-create the formula.
Message 3 of 4 , Jun 8, 2011
I think the 3-1 was a typo and they meant 5-1.

I guess the original research by NOAA was lost and they basically used the table to re-create the formula.

--- In wuhu_software_group@yahoogroups.com, David Lipper <glenvilleweather@...> wrote:
>
> Thanks!
>
> Hmm, the formula gives a lower number for IAT (Heat Index) than the actual temperature.
> That seems counter-intuitive. It talks about mean error of .608, and maximum error of 1.98, but dismisses that.
> It also refers to numbers in figure 3-1, but the paper is missing that figure.
>
> The tables they do include (5-1) cover only 61 to 75, so perhaps this formula is not appropriate for temperatures above 75.
> In fact, the cause given for using this formula was that the conventional (US) heat index is only suitable for 80+F.
>
> On 2011-06-08 17:29, wuhu_software wrote:
> >
> >
> > David,
> >
> > In the files section, check out:
> >
> > Files \ Weather Algorithms and Formula \ Indoor Comfort Index.doc
> >
> > --- In wuhu_software_group@yahoogroups.com <mailto:wuhu_software_group%40yahoogroups.com>, David Lipper <glenvilleweather@>
> > wrote:
> > >
> > > Hi, Heath, how do you calculate the indoor apparent temperature?
> > >
> > > Using version 1,0,216,184, I get (by hovering) IAT=83.3F at IT=84.2F, IH=50.0%. That doesn't seem right.
> > >
> > > A calculator at http://www.weatherimages.org/data/heatindex.html shows IAT=85F with the same input values.
> > >
> >
>
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