I'm thinking a radiant barrier would help a lot. Actually, just about
any barrier would probably help. I asked about radiant barrier paint
today at a box store and the paint guru said they had glow in the dark
paint and fluorescent colors. I said nothing and walked away with a
permanent loss of an IQ point. I saw I could get 1000 sq ft of radiant
barrier online for $100 and $40 shipping, but installing it would be an
interesting challenge. That's probably the way to go for the long run
I had our builder install radiant barrier paint. They applied it on the
underside (visible from the attic) of the roof decking. I'm also in
Texas (Dallas area) where the temps are currently getting to the high
90's. I honestly don't know if the paint helps, because I have nothing
to compare it to. My cooling bills are still very high, but who knows
how high they'd be without the paint. We also did the blown cellulose
insulation, which certainly looks like it would be more effective than
the standard stuff. That attic still gets very hot so I'm thinking that
the paint is not that great, or there was a problem with the way it was
I have the same problem as the OP in my gara..shop. It's a three car
garage with the metal doors facing west and it gets downright toasty in
the late afternoon. I just added panels of of exterior sheathing (foil
on one side, R5 value)and I really don't think it helped much. I'm now
comtemplating an exhaust (or intake) fan arrangement of some sort. I
have a side door which is currently unused and blocked by equipment,
but I could utilize it for a fan. The door is near my shop area and I'm
thinking I could set up a heavy duty box fan to pull in fresh air
through an AC filter and crack one of the garage doors to allow the air
to escape. That way I'd be pulling slightly cooler air from the east
and exhausing it to the hot west side.
I could also install a window AC unit in that door, but I think the
cost to operate it would be astronomical.
I believe the radiant paint is a Sherwin Williams product. And, I
believe it is available as an interior wall paint, in colors for those
rooms that catch a lot of sun on their exterior walls. I've heard it
opined that if you are not going to condition the space then insulation
is not the way to go. But, maybe that's just for high humidity locales
I'm also not a fan of blown-in cellulose insulation. I'd be afraid
it will break down as the years go by, make dust. Not to mention the
chemicals it's likely treated with.
Exactly. Inslulation does not warm or cool. It slimply slows down the
transfer of heat to a cooler spot. If you are not keeping the inside a
constant temperature there is really no reason to insulate. The reaiant
barrier however keeps the structure from absorbing heat.
I think the new stuff will work better. The old kind would settle and do
like you said. The new cellulose however has an additive that sorta lightly
glues it in place so that there is no settling. Ryland homes is using it
and the can demonstrate how well it works at the model home sales offices.
It really beats the pants off of the pink stuff for efficiency and sound
here in n.c. it gets pretty hot in the summer months. do you have
vents at each end of the building? if so, you could put a large fan
blowing out at one end. my shop is uninsulated also exept for the foam
sheating under the siding. nothing in the roof. it is under a few
shade trees and 2 story so i am sure that is helping. my shop stayes
cool up till around 4 pm in the summer. after then i go to the house.
if you dont insulate then ventilation and air flow are the key to
keeping cool. on days i want to work in the late afternoon i set a fan
blowing in downstairs and one or two blowing out upstairs. seems to
work ok. i have a window a c unit that suposedly works. havent ever
pluged it in so i cant say weather it does or not. you are welcome to
it if ya want to haul it home. maybe it willl make it cooler to work
in there but might be kind o exspensive. lol.
How about actively removing the heat: a gable-mounted exhaust fan, with
or without a thermostat control. Depending on the CFM, you'll need a
certain area of "inlet" into your shop of fresh air - got a screened
The collateral benefit to the exhaust fan is it moves out the fine dust
Hax Planx wrote:
It dropped the temperature in my old shop from scorching hot to
whatever temperature it was outside in a matter of minutes, and it
sounds like you have exactly the same situation in yours. IIRC, they
had some vent fans that mounted directly to the inside of the roof
right next to the ones mounted on the wall at the hardware store, so
that may be easier.
IIRC, (and it was a couple of years ago) they were hooded. I believe
there were some louvered vents as well, but I don't know if I'd trust
those in a roof, especially after they've been in there for a couple
I cobbled a swamp cooler together to use in my garage here in the
Dallas area. Box fan with a mister in front of it, water feed from a 2
gal jug. Not fancy but it helps. As outside humidity rises, it becomes
much less effective, but below 40% relative humidity it drops the temp
about 15 degress if ambient temp outside is >85 degrees F. It does,
obviously, raise the humidity in the garage a bit.
Why not a swamp cooler for 1000 sq. ft.? Today, I saw a $350 unit at
Home Depot rated for 800 feet. The $450 unit was rated for 1500 feet.
It's not for your square feet. It's for your comfort, right? :-)
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