Solar Attic Ventilation in Florida

[Dave Saxton]

Hello. I live in central Florida and was looking for ways to help curb
some of my high electric bills. I have switched over my lights to the
energy efficient types and am looking for other ways to conserve. My
A/C seems to run all of the time. I keep it set at 78-79 on most days.
I was looking into the possibility of solar-powered attic fans to go
into the gables in my roof. However, I read somewhere that this might
not be the best thing to do because I would essentially be pulling
more humidity into my attic and increasing the possibility of mold and
other such issues. Does anyone have any information on this or maybe
could offer some other insight? My next step is to find out more info
about my hot water heater and I also have a pool pump that runs about
8 hours a day. Any suggestions for those would be helpful as well.

Go easy on me... I'm a newbie at being green

Dave

 

[Dave Saxton]

That seems pretty reasonable. We purchased this house in August 05. It
was built in 1981, and the A/C unit is the original. There is a bunch
of white insulation that covers the entire attic. It is loose, not the
rolled out pink panther stuff I have seen at Home Depot. However,
underneath the white stuff is the pink panther stuff. Does that make
sense? I have 3 gable openings in the attic as well as an opening
that goes along the very top of the roof at the peak. It's covered on
the outside. I forget what kind of vent the home inspector called it.
I also thought the ventilation was okay. The thickness of the pink and
white insulation together is only about 6-8 inches, so that is
probably where the problem is. The A/C tested okay and part of the
contract was to have the unit inspected and serviced. I am wondering
if it is time to get a newer, more efficient unit?

Thanks for the input!
Dave

 

[Rheilly Phoull]

Hello. I live in central Florida and was looking for ways to help curb
some of my high electric bills. I have switched over my lights to the
energy efficient types and am looking for other ways to conserve. My
A/C seems to run all of the time. I keep it set at 78-79 on most days.
I was looking into the possibility of solar-powered attic fans to go
into the gables in my roof. However, I read somewhere that this might
not be the best thing to do because I would essentially be pulling
more humidity into my attic and increasing the possibility of mold and
other such issues. Does anyone have any information on this or maybe
could offer some other insight? My next step is to find out more info
about my hot water heater and I also have a pool pump that runs about
8 hours a day. Any suggestions for those would be helpful as well.

Go easy on me... I'm a newbie at being green

Dave

If you have high temps during the day then a solar HWS would make sense,
another area to do sums is the pool filter. If its a chlorinator which has
to run 8hrs to make the chlorine check on wether its cheaper to buy liquid
(or whatever) chlorine to add to the pool along with an anti fungal and cut
back on the filter time. Our pool stays good in summer with 2hrs (1 hr
morning and evening) by adding chemicals rather than using a chlorinator. We
live in Perth West Australia which has the odd high ambient temps during
summer ;-)

 

[[email protected]]

Pool pumps is a big energy user ( its usually a bigger drain than your
water heater). Correctly matching the pump size to the pool, shortening
the pumps operational hours, using a pool pump timer, and keeping the
pool traps and filters clean will minimize the energy cost.

The guy at http://www.powermat.com/pools/pumpsize.html by far favors much
smaller pumps with much longer run times. He claims that length of run
improves water quality, and the smaller pump uses less energy overall, with
less demand on filtration.

We stopped conversing over misconceptions about head pressure, but I don't
know about the rest. He claims to have some research on his side.

 

[digitalmaster]

If your AC is running all the time set at 78, your insulation must be nill

I'm in central Florida and even in the 90+ days, the AC only cycles about
25-30% on in the mid afternoon heat, 10 year old house. You should have
R30 minimum in your attic, about 12" deep... It's cheap to have a company
come and blow in fiberglass around here , typically 500.00 to get you back
to R30+, that should be your first priority as its probably about 80%+ of
your bill if your AC is constantly on

As for the vents, you should have either ridge or covered vents already,
that naturally draw in air from the soffit which with proper insulation is
all that is needed for proper ventilation. One also not be adding more
ways for wind driven rain to enter the attic, pretty common issue here
with our common storms

Properly sized a/c unit is supposed to run almost continually during the
hottest part of very hot days.If your unit is only running short cycles
during the hottest part of the day it is oversized.An oversized a/c will
lead to higher power bills and humidity problems.
For example if you have a properly sized unit you can set the thermostat at
78 and be comfortable because the a/c runs a large enough percentage of the
time to control humidity.The longer the cycle of the a/c the more efficient
it becomes.
However with an oversized unit it will quickly drop the temperature in the
house without removing much humidity.Consequently you may not "feel"
comfortable at 78 and have to keep the house at say...72 or 70.
Anewer more efficient unit will save much power,but be sure your service
person does a heat load calculation to properly size this unit.As far as an
a/c unit goes,bigger is not better.

 

[digitalmaster]

That depends how you use it. If you turn the beast on at the first sign of
heat and turn it off shortly before Christmas then maybe you can utilize a
smaller A/C unit.

However, if you are like most people and like to save a little A/C money
by opening tyhe windows on nice days then when the heat and humidity hits
you are goiung to suffer sleepless nights because your unit is sized too
small to recover in less than a few days of running continuously. This is
harder on the unit, and you live with discomfort many times during the
season as you will not know the A/C is going to be needed until it is too
late in the day.

Installers are starting to reverse that old concept of undersizing the A/C
unit. It didn't work as well as was originally thought, depending on
climate.

I did not say undersize it I said properly size it.A Properly sized unit
does not take several days to recover.Neither does it short cycle.
Running is not "hard" on a unit.Short cycling is.

by the way..I KNOW what service techs are recommending.

Plumbers, Pipefitters, and Service Technicians local 72
card number 1465687

 

[digitalmaster]

When you size a unit to never shut off on peak usage times you have
undersized it.

You play semantics and rip your customers off with a undersized unit. I
had one of your "correctly sized" units ripped out and replaced with a
amply sized unit. Sure I have a little more humidity but I can have my
windows open many times in the summer season. Not many with the "properly
sized" units, as you call them, cam do that. The windws are closed for the
whole season and multiple guests in the house always get cooked.

I had many "professionals" give me estimates before installation. Ohh
yeah, they measure windows and go through all the techno bullshit and then
suddenly make a decision when they see the 60K BTU rating on my furnace.
"Your need a 2 tonne unit" they all said. Meanwhile the furnace guy comes
back after a year and asks if it was ever too cold because he sized my
furnace too small for the house. I have so much solar gain with 3 complete
floors exposed on the south side.

Anyway after 15 different visits with equipment, more bullshit
measurements and many recommendations about adding awnings and opening
registers that blow on the thermostat to make it shut off and cook my
bedroom at nights I demand the SOB take the GD thing out and install my
own. 2.5 tonne outside unit with a 3 tonne A coil and a matched orifice
valve. Never been happier.

Don't bullshit a techno guy with technobabble learned in nightschool while
on unemployment.

the only bullshit is pouring out of you

However, if you are like most people and like to save a little A/C
If you open a window on a nice day there will be no problem.

What's this about a system taking days to recover???

I am sorry you hired the lowest bid hack a/c man who did not have a clue.

I do not undersize systems.If it is 100 degrees outside..your a/c should be
running.

I have not told you any technobabble.If you think this is technobabble you
really are clueless.

You seem to think that a unit is either too big..or too small...never right.

Obviously your guy undersized the unit and did everything he could to not
have to fix it.I suggest reporting him to the BBB or Chamber of Commerce.

That does not mean if the a/c guy recommend a 3 ton you tell him to put in a
five.

Be a reasonable human being and use your brain...not emotion to make
decisions.