[Greenbuilding] temperature stratification rule of thumb (in two-story house)?

Topher topher at greenfret.com
Wed Jul 9 20:24:34 CDT 2014


On 7/9/2014 6:28 PM, RT wrote:
> On Tue, 08 Jul 2014 20:47:19 -0400, Reuben Deumling <9watts at gmail.com> 
> wrote:
>
> >To my chagrin, the temperature in the now much better insulated 
> portion is no different than in the equivalently oriented part of the 
> upstairs.
> > Both are only about 7 degrees cooler than the outside
>
> The improved thermal insulation that will hopefully keep the occupants 
> toasty in winter doesn't know that you don't want it to keep heat in 
> the house in summer.
>
> Stoopit insulation. Eh ?

No, that isn't the way insulation works.  It simply slows heat transfer 
from hot to cold.  If the house is cooler than the outside, the 
insulation is HELPING keep the house cool.
>
> In addition to the 30 degC-plus outdoor temps in summer, there are 
> still the internal heat gains due to occupancy and solar  gains from 
> the S/W-facing glazing which are no doubt appreciated in winter but 
> it's not the job of the insulation to get rid of that same heat in 
> summer when it's not welcome.

True, but the insulation's job is to keep the 30+ outside from getting 
in.  Which it is.  Unless internal heat gains raise the inside higher 
than the outside temp, the house should be cooler with insulation than 
before.
>
> That job falls to stuff like shading devices , ventilation strategies, 
> thermal mass etc. ... and I would not under-estimate the role that 
> significant amounts thermal mass can play in helping to provide large 
> temperature differentials between inside and outside.

Thermal mass does nothing to provide large temperature differentials 
between inside and outside.   All it does is require large amounts of 
heat to change temperature.  Whether you want more or less is a 
complicated question based on climate and other factors.

Thank You Kindly,
Topher

-- 
Topher Belknap
Green Fret Consulting
Kermit didn't know the half of it...
http://www.GreenFret.com/
topher at greenfret.com

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