On Fri, 04 Jul 2014 04:11:00 -0400, rickman wrote:

On 7/4/2014 12:28 AM, Jeff Liebermann wrote:
On Thu, 03 Jul 2014 18:40:06 -0700, RobertMacy
wrote:

Ceiling exhaust fan !!! when it's 105 outside no way!!! you want me to
suck in outside air at those temps??!!

Let's see at night 81 during day 105, making the average high side of 93,
sounds about right.

I thought it gets kinda cold at night in Az. I've only been there
once. It was quite hot during the day, but we nearly froze sleeping
in the car at night.

Since I painted my house a darker color and take advanatage of 'night time
radiation' the average in our house has dropped substantially. Who would
have thought? dark house = cooler average, light colored house = hotter
average. but true we noticed a difference the moment the house was painted.

In some areas, white rocks and white roofs are required by code to
reduce air conditioning requirements. It's suppose to reflect the
sunlight instead of absorbing it. Now, you're telling me that the
collective wisdom of the local planning department might be wrong? Are
you sure?

I initially thought he was wrong, but consider the two situations. In
the day the house is absorbing sunlight radiated from the Sun at many
thousands of degrees. At night the house is radiating heat into the
void at around -273°C. I'd say the more significant factor is the
daylight situation, but the devil is in the details and I would love to
see some real data on the situation.
Well, our house is pretty well shaded by the tree canopy in the
summer - so the absorption heat gain is not terribly high - and it
generally isn't hot enough that the colour of out roof would be an
appreciable factor in radiating heat over-night, but if /when it gets
really Mugglyhot the darker roof is likely an advantage. Often the
Mugglyhot days co-incide with significant cloudcover around here too.
(Mugglyhot = Muggy/Ugly/Hot weather from hell -used to only get a
couple weeks of it, split up into short periods of a couple days -
lately we've been gettin 2 week stretches several times per summer.)