I have one room in my house, a southeast facing room, that gets damn
hot...the rest of the house can be 72 degrees and this room will still
be in the 80s with a ceiling fan going full blast (i live in Houston,
Texas)...the room is also over the garage....it has one window that
faces south and is double paned and one door that is double paned that
faces east to an outside porch...i am thinking about having extra
insulation injected into the walls
my questions to this great group are
1) do you think the extra insulation in the walls will help
2) what is the deal with reflective insulation and should i consider
adding that to the mix
3) are there any suggestions in general to get this room more in line
with the rest of the house and keep it cool...it is my office and i
have to move into the kitchen in the summer!
Insulation will help but the window might be the cause, Unless it is
LowEargon it is heating your house. www.energystar.gov has alot of good
info. Can you run another Ac duct or balance your system to force out
more air, has your AC been checked out.
What makes you think there is any room for additional insulation? If
this is std stick construction, there normally is as much insulation as
is practical to put in the walls already there. You can't put more on
top of it.
Is the floor between the garage and room insulated? Perhaps most
important, how much air flow is getting into the room via the AC?
It's not unusual to have this problem due to poor AC install. Lots of
times they use too small of a duct and run it too far.
I'd carefully check the ducts and make sure nothing has come loose,
disconnected, all dampers are open, etc. There are also booster fans,
two types. One goes over the register in the room and plugs in an
outlet. The other goes inside the duct at an appropriate point, eg in
the basement before that run heads upstairs. I have the later type
for a room I was having a problem with. It definitely helped, but it
didn't make it perfect.
Where are the returns located? Is there one in that room? Sometimes
making these larger can help. I'd also check your attic ventilation
situation and make sure it's adequate. You could also consider
planting a large shade tree or two, which would block the sun and could
be a major benefit, though it will take time to grow. From a practical
standpoint, it might come down to using a small window unit to cool
Check the windows and use everything possible including awnings.
Check for a closed damper in that duct-run.
Is the duct big enough and the diffuser adequate to deliver the correct
amount of CFM air to that room according to the heat-load calc?
Check out my web pages:
- udarrell - Darrell
Air Conditioning\'s Affordable Path to the "Human Comfort Zone Goal"
This may sound very silly and obvious, but do you have a computer on in
that room for long durations? I had a friend who complained that their
room was always much hotter than the rest of the house (and it was).
The problem turned out to be that they had a computer in that room that
was on for 12-18 hours per day, and their computer generated a lot of
heat. Certain CPU brands and models generate much more heat than
others. For example, the Intel P4s, and AMD 64 FX CPUs are big
generators of heat, and some models generate over 100W of heat
As a test to see if your computer makes a difference, keep it off for
the day and see if you still find the room to be much hotter than the
rest of the house. Or keep your computer on with the door closed all
day long (make sure you configure your computer not to go into power
savings mode), and see if the room is much hotter than the rest of the
house when you open the door after 4-6 hours.
If the room is an office, printers, fax machines, UPSs, and CRT
monitors are other generators of heat. Together with a power hungry
computer that's on for long hours, they can generate quite a bit of
--> I forgot to specify that the 100W of heat is from the CPU alone.
So for a whole computer, throw in an advanced video card, a 500 Watt
power supply, a high RPM hard drive, a 21" CRT monitor, a high speed
modem, and a CD-RW or DVD-RW (that's being used), and you've got a
mini-furnace in the room.
The CPU/MB and drives uses the power from the power supply and exudes it
as heat. Of that 500watt power supply, only what it wastes, a small
amount, they are quite efficient, is dissipated as heat.
If I had something witty to say, this is where I'd say it.
You need to remove the hot air that is going to build up in that room
from the equipment that is producing it. A return vent up high is what
you need, so that the hot air gets sucked in, and gets cooled by a/c.
A worst case scenario, is you install a special a/c for that room.
If you have a lot of equipment, installing a window ac unit, set at a
higher temp, will serve as a backup in case the main unit fails.
Then have someone do the proper manual calculations, and tell them to
include the extra load created by the equipment.
I had a back bed room I tried to use for the same purpose, but until it
got a return vent into the room, nothing helped. And a return vent up
high in the room is what works best for a/c.
If I had something witty to say, this is where I'd say it.
My bet is on many factors all making contributions.
You should not be able to insulate the walls more than they are without
some new construction to allow more room for insulation. Reflective
insulation will not likely help a lot in your situation.
I suspect the real problem is two part. First you are gaining more
heat into that room than others because of the garage. Heat is coming in
from the walls and ceiling like other rooms, but you are also getting it
from the floor. Part two is the heating/cooling system was not properly
designed to handle the load on that room. The real answer is to have a good
HVAC tech out to do the numbers and make recommendations that are likely to
include modifications to the air handling systems and/or additional cooling
question for you joseph...had an HVAC guy out as you suggested and my
units for the house are more than adequate (actually the guy told me i
had too much)...he said the insulation was good also and recommended
running another duct to that room....seems that room is far from the
unit but the unit can handle a couple of more outputs...he quoted
300-350 to do the job....what do you think?
Joseph Meehan wrote:
It sounds very good. He was able to see all the things we could not see
from here. His suggestions appear sound and the price seems low (however
that would depend on the specific situation).
The part I can't say is if he really is making some good judgment calls,
but there is no way of judge that from here.
Sounds like a damn good deal to me. Many times, it can be impossible,
or next to impossible to run a new duct to a remote room, without
tearing the house apart, building a chase, etc. Can't say if it will
cure the problem, but it will certainly help and should make a
when you say making good judgment calls what exactly are you refering
to??...what judgment calls are you assuming he is making that might be
questionable or that maybe i need to watch out for?
thanks again for all of your help!
Joseph Meehan wrote:
Well, judgment is not really the best call as if they do it the right
way, doing all the measurements and calculations there is no judgments to be
made. In real life there are judgments, even if it is to make informed
guesses based on experience about things like how likely is a duct to be
insulated when you can't really see it. (The answer to this is likely to be
different in Florida than in Ohio.) It also may mean taking a good look
around make guesses or off the top of one's head calculations about duct
size, length, number or turns, insulation effect of windows etc.
The choice of what to carefully measure and what to make judgment calls
about is in itself a judgment. You want a competent HVAC professional.
That is why it is best to ask around and see if family, friends or neighbors
have some recommendations.
It takes years of experience to gain the knowledge to make good
I have a very similar problem with one hot room in my house. It also faces
southeast, upstairs and shares a wall with the attic over the garage.
Am curious. Did the additional return vent solve your problem?
Ceiling fans will blow the air around, but if anything, they add a
little heat to the room. Motion is equivalent to heat.
In the summer time, they take the hot air that rose towards the
ceiling, and they blow it down to where the people are. If the people
are perspiring, the evaporating sweat will make them feel cooler, but
other than that, fans don't cool anything.
That said, all I use for comfort in the summer is table fans, one in
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