Doesn't do a thing for life on the Gulf Coast.
The number of hours where we are off the end of this table (i.e. greater
than 80F AND greater than 80% RH) is over 6000 hours a year. Travel
away from here in almost any direction and lips will chap and crack.
Hard to believe, with only 8760 hours per year. Then again, YOU are often
hard to believe. Perhaps your town has lots of 10 day wintertime months :-)
NREL says the average daily MAX temp is less than 80 F from October
through April in New Orleans and Port Arthur, less than 80 from November
through March in Corpus Christi, and so on.
as one local guy put it, we have 11 months of summer, and then there's
NREL does not accurately depict what Houston weather is like. RH is
almost always above 50% and in the summertime, the air has WEIGHT when
stepping outside on a sunshiny day with temps in the 90s and RH nearly 90.
Year round apparel is short, tshirts and sandals. The number of days
where the temperature at any time of the day drops into the 30s can be
counted on your fingers and still have fingers left over. In the nearly
30 years we have been here, it has snowed twice and we've had one or two
Well, They've only been measuring it every hour for the last 30 years
in Houston... They say the average daily max in Houston is less than
80 F from November through April. That's 6 months, ie 50% of the year,
ie 4380 hours. The 24-hour average temps in May through October are
74.5, 80.4, 82.6, 82.3, 78.2, and 69.6, which eliminates 6 months of
nights, another 2190 hours. There are only 2190 hours left in a year,
on this planet. How many hours per year on your planet? :-)
Oh. That's different. The air has WEIGHT :-)
That statement has little to do with your claim:
How can you combine such a huge ignorance with such a huge arrogance? :-)
Looking at weather.com, average high temps are above 80 from April thru
October Average low temps are above 60 for the same time period.
Average precipitation per month ranges from just about 3 inches to
almost 6 inches.
Record Highs are All above 80 for the ENTIRE year.
Record lows are all above the freezing point from April thru September.
wikipedia.com says average annual precip is 48 inches here with
prevailing winds from the south and southeast for most of the year
bringing heat from Mexico deserts and moisture from Gulf Of Mexico.
"The air tends to feel still and the humidity (often 90 to 100 percent
relative humidity, while average afternoon relative humidity is between
57 and 60 percent in the summer) results in a heat index higher than
actual temperature. To cope with the heat, people use air conditioning
in nearly every car and building in the city."
My thermostat is set to 80F, we have two ceiling fans and a box fan to
keep the air moving in here and we still feel quite warm
The number of weeks in the year where the outside air temp is in an
acceptable range and the RH is also in an accceptable range to allow
one to open the windows and doors and let the outside air in, is a very
very small number of weeks, my estimate is less than 3 weeks of the
We visited Palm Springs in the heart of the summer several years ago.
Outside air temps were well above 100, approaching 110. It was a VERY
pleasant environment for us as the temps were only a little above what
we were used to, but the humidity was so much lower (course we paid
with severely chapped lips as a result)
You deliberately misinterpret what I said. The data shows that the
high temp for ANY given month in the history of record keeping for
Houston TX, even in January and February, there have been days where
the high temp was above 80F. The AVERAGE high temp is above 80F from
April thru October.
Arrogance, hardly. The shoe clearly is on your foot not mine.
I invite you to spend a year on the southeast Texas Gulf Coast and
then tell me that I am full of it.
OK, 6000 hours was way too high. I got interested after you made
BTW way do you continue to use BASIC for these simulations???? C
or C++ will do the job as well and most anyone with a technical
background can understand
I stand my my claim after living here since 1982, there are only
about 3 weeks of the year when the temperature is in the right range and
the humidity is in the right range that we want to throw open the
windows and doors to let the nice outside air in.
Right now, we are in a low humidity state. Outside air temp is in
the low 90s (TV says 90, my local in the shade thermometer is 92). RH
is 43%, lower than average for afternoon temps. NO WAY DOES ANYONE
WANT THIS AIR INSIDE!! Forecast temps for the rest of the week are
highs of 94 to 97 and lows of 71 to 72.
$75 for heating for the ENTIRE winter is NO joke. Thats all I spend
TOTAL for the ENTIRE YEAR!!
On what basis is this argument???
Seems to me that the more water vapor per cubic meter, the heavier the
volume of enclosed air is.
Hot air will rise over the top of cold air, yes, but hot is not
Well, things are not always what they seem. Mercury, at room temp, is a
liquid, yet is nearly twice as dense as solid iron. It is true that moisture
laden air is LESS dense than dry air at the same temperature.
I did not say that hot air is necessarily humid... I said that humid
air is lighter than dry air at the same temperature and pressure.
So for example one cubic foot of dry air at 90 degrees Fahrenheit and
one atmosphere pressure is HEAVIER than one cubic foot of humid air at
the same temperature and pressure.
The reason is simple: air is mostly nitrogen. Nitrogen occurs
naturally as a diatomic molecule, N2. Water is H2O. Use a periodic
table to figure the molecular weights of the nitrogen molecule and the
water molecule. You will see that the water molecule is much lighter
than the nitrogen molecule.
It might also help in explaining to point out that, at a given
temperature and pressure, a given volume of gas contains the same
number of molecules no matter what those molecules are. This isn't
exactly the most intuitive thing: after all, it's not how solids
OK, OK, Its not weight we feel.
Still air with high humidity prevents our skin from effectively
dissipating heat thru evaporation of sweat. The brain interprets this
as weight, somewhat akin to the feeling of suffocation, but very very mild.
This will be the LAST time I EVER respond to ANYTHING that Nick at
Villanova posts to the alt.home.repair newsgroup.
For those of us who live in the region that NREL classifies as
Humid-SemiTropical, lots of things that work elsewhere do not work
here. For Instance.
Vapor barriers go on the OUTSIDE of the house, insulation is ALWAYS
unfaced, and vinyl wallpapers should NEVER be applied.
Vegetation should never be closer than 3 feet from the house, and an
appropriate ground cover should be maintained over than area. Ground
should slope away from the foundation at least 2 inches per linear foot.
Windows on Southern exposure sides of the house should be eliminated, or
scaled back in size dramatically if elimination is not possible.
geothermal heat pumps will either require open loop cooling, or will
require multiple large diameter wells, 400 feet or more, likely two of
these per ton of installed capacity to make a closed loop system.
RH levels outdoors much of the year make outdoor activities uncomfortable.
Construction workers all wear long sleeves, hats and scarves to keep the
sun off their skins. Even the very low paid yard care crews do this.
Natural fiber clothing is preferred in most regions as polyester and
rayon are poor at wicking perspiration off of the skin.
I wear sunglasses ALL the time when out of doors.
Relative Humidity levels and temperatures for most of the year are such
that the struggle is almost always to keep moisture out, as we are NEVER
too dry inside.
In the new house I will build, I MAY decide to include a ventilation
damper to allow the ventilation system to inject some fresh air from
time to time AprilAire makes one that is reasonably priced, it wont
open the vent trigger the fan unless outside air temp is under 100F and
over 0F, or if allowing the ventilation would cause indoor RH to rise
above 55% However these requirements mean that the damper will not
operate for most of the summer. The plus side of this is that it runs
the fan in the hvac while fresh air is introduced.
Nick, your system should closely model what the AprilAire Ventilaion
Control System Model 8126 does. The more deluxe ERV as documented at
www.ourcoolhouse.com works ALL the time, exchanging heat and moisture
with outside air. This one works better in climates that have 4
seasons, and ourcoolhouse is located in Colorado.
Nickie is a math and theory lover. That can be great if you want to
know how much heat a standard ASHRE mouse puts out, but Nick sometimes
gets confused when confronted with the fact that not all mice are
Weather station instruments are commonly placed at airports or other
open areas. That may not be representative for an area that otherwise
has dense vegetation and/or standing water. Airports have to be level
and dry enough to land planes, and they also usually have a lot of
paved or concrete areas and low cut grass. That means more wind can
sweep the ground, less groundwater can be transferred by vegetation
into the immediate air, and temperatures and humidity can differ from
If Nick builds his constructions on or near a runway, he may be right.
If he builds on a typical wooded or swampy southern lot, he may find
the real world intruding.
In other areas, the representative weather stats can be off because
the weather instruments are NOT at an airport. I used to take
measurements at a radio station where my father worked. That station
was (logically) on a hill, and the town below might be lost in fog
while I was recording clear skies, low humidity, and a mild wind for
the town. Fast foreword a few years. Now, another weather reporting
site in that community is located about 50 feet above a river, at a
spot where it enters a small canyon. It also has different
measurements than if you set up a station in the middle of the small
town. On a practical basis, weather is an extremely local phenomenon.
Here in south Florida, I have become accustomed to seeing rain-soaked
streets that are totally dry 500 feet up the road. I've had my pool
fill with four inches of water, while the airport reported no rain at
all. The heavy rainstorms here can be that localized. Depending on
the winds and the season, the coast may get strong breezes and a cool
temperature, while five to fifteen miles inland, clouds billow up and
create a line of storms that never touch the coast. You can't always
go by reported weather from a selected set of sources
Having been through southern Georgia many times, I know there are
large differences in temperature and humidity around the peanut and
cotton farms compared to the pine forests and towns. That is common
sense and experiential knowledge.
However, Nick takes it as an article of faith that discrete samples
from professionals always represent a greater norm. :-)
FWIW, I've used economizer dampers on theatre HVAC units in Vermont
and in Alabama. The greatest use was over Christmas vacation, when
crowds would overheat the theatre and the outside air was less than 40
degrees F. Much of the rest of the time in Vermont they had to be
sealed with plastic and duct tape to prevent drafts and heat loss.
The integrated ones also had more electro-mechanical problems than
other systems. That may have been design related - unsupported lever
arms, corrosion, ice, etc. but they were only marginally cost
effective overall. In Alabama, the vents were straightforward exhaust
vents, and were used only if the AC was overwhelmed or there were
smokers (which were still allowed in certain sections of some
Whole house fans were common in the south before AC, and venting is
just a variation on this. The success of those whole house fans often
depended on measures such as opening certain windows after 10 PM and
closing the house up tight before 8 AM, drawing all the curtains, and
sweating out the early evening on a porch. Once AC became affordable,
life changed for the better. Getting people to go back is nearly
impossible, and Nick should know this, but his stubbornness lack of
experiential knowledge prevents it.
Houston has two measuring stations, the airport, with a 96' elevation
and a 96 F 1% summer design temp, and "Houston County," with a 108'
elevation and a 97 F 1% summer design temp. Not vastly different :-)
Automatic controls can turn on a fan when outdoor air is cooler and drier
than indoor air, in the absolute sense. This is quite recent, with existing
unexpired patents for drying out houses after floods and so on. See
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