We live in Denver. Our home is about 3,500 Sq Ft with a 3 car garage.
We have central air conditioner. It cools the downstairs great. But
the upstairs can get quite hot. The garage is on the west side of the
home and gets hotter than 40 hells in there during the summer. There
is a south facing gable in the garage. Two bedrooms are above that
hotter than hell garage.
Question 1: Would a power fan mounted in front of that gable suck out
the hot air in the garage even though there isn't another gable to
bring in the cooler air?
Above the three bedrooms upstairs is an attic that gets hotter than 47
hells. There is a gable on the east side of the house and one on the
west side. I'm thinking something with a bit of power up there could
suck that hot air out and help cool the upstairs vs what it is doing
now and radiating down into the living space. Here's the twist. We
also have a whole house fan mounted upstairs of course. But that
sucker could substitute for an engine for a small airplane. Works
great but forces us to open windows which defeats the purpose of the
central air conditioner. If we don't open windows our home starts
smelling like soot from the fireplace. I know this is getting long so
thanks for making it this far.
Question 2: Based on the facts above what is the best way to remove
all that hot air out of our attic?
Lastly, my daughter's bedroom is on the west side of the home. Anyone
who knows Colorado knows the west side of the home cooks in the
afternoon. To make matters in her room worse .... her vent barely puts
out any air. It's been like that from day one. So her room gets hot.
Question 3: Based on what you know about my daughters room would it
help to have someone install an in duct fan to push more air through
her vent? Those $39 register fans I see at Home Depot just look
worthless but I've never bought one so I really don't know.
Last part I promise. Our home was build in 1984 and the attic has a
bunch of blown in insulation. Should that be removed and then replaced
with newer and better insulation?
To those who made it this far thanks. I appreciate your patience. To
those who give suggestions even more thanks. I've always found this
newsgroup to be very helpful when it comes to stuff like this.
out of the attic floor. Just add more insulation with no
additional vapor barrier. Then ventilate it. Lots of vent area very low in the
and lots of vent area very high in the attic. Powered vents might help, but
venting is better if you can make it work. The gable vent may "short-circuit"
low/high convection air flow, so you may need to block them. Remember - hot air
you want to take advantage of this. Try to arrange the vents so the air flows
the whole attic - there should not be "dead" spots.
Plant a to-be-large deciduous tree west of the house.
Be aware that this advise comes from Seattle. YMMV.
We have a 22 year old Ash tree out front. It helps. But keep in mind
Denver has 300+ days of pure sunshine. That's why I live here. Summers
are much hotter than people think. No humidity but hot.
Ok now I expose my ignorance. What the hell is a vapor barrier?
hot air rises, air is lazy, hvac additional zone your second floor,
hvac additional zone your problem areas, integrate ventilation air by
powered dampers into the hvac system, use indoor and outdoor sensors to
monitor your sanity and both temperature and humidity, remember that
you desire fan ventilation only when the outside air is more
comfortable than the inside air, don't waste money on noisy fans,
nobody is going to put the fans in and out of the windows except you.
also, isn't the whole house fan already blowing the unwanted summer
heat from the upstairs hall into the attic where it exits the house
attic thru vents?
knowledge: read all about ventilation and comfort levels at:
hmmm. havac additional zone my second floor. What exactly does that
mean? A separate a/c for the second floor? What are powered dampers?
Reread my post. We don't use the whole house fan because that forces
us to open up windows which sucks in dust and defeats our a/c. I'm not
sure what you really said here. Sorry.
sounds like you need a couple of power vents in the roof. These are simply
fans permanently mounted through the roof, and attached to a thermostat. At
a given temp, they turn on, and start sucking the hot air out of the
attic/crawl space. They're not that expensive, and if you're comfortable
playing with roofing, they're easy to put in (if not, a general contractor
should be able to put them in for pretty low bucks). They draw air in
through the soffit vents, so convection is helping too....
The whole house fan i s *supposed* to pull air through the house. if you
keep the windows closed, it will suck air back through whatever opening
there is - usually a chimney - so you may be pulling air back through your
furnace or a fireplace or some such, hence the soot smell.
I wouldn't bother with playing wiht the insulation - no matter how well you
insulate the attic floor, unless you manage to get the temp down, you'll get
heat penetration. Better insulation will help a bit, but you really need to
get the attic temps down....
the idea for some shade trees is a good one. It won't lower the general iar
temp, but it will help keep your roof from baking, which is whats making
your attic so hot. those roofs really soak up heat - I live in New
Hampshire, and a few years ago I was doing a roof in January when it was
about 20 below zero. On a sunny day, it was warm enough on the roof to work
in T shirts (and there was no heat in the building at the time....)
I'll look into this. Who does this type of work? A roofer?
I can assure you it is from our fireplace which we use in the winter
time. This home originally had no central a/c which is not that
unusual for Colorado. So the previous owners used the whole house fan
a lot. We installed central a/c many years ago so the whole house fan
Shade trees are great. But keep in mind this is Denver. Every tree in
this city was planted by a person. This is basically high planes
Unless it seals very well, the shut-off whole house fan is probably a pretty big
source of leaks for your A/C'ed air. If you don't use it, you might want to seal
If you add power ventilators to the roof, unless you have lots on inlet vents in
your attic, the fans will suck air from your house through the whole house fan,
any other leaky spots that exist. With the kind of heat you are talking, there
be ways to get good convection ventilation without the power. I bet a properly
coupola would do wonders. Ridge vents are supposed to be pretty good.
It sounds to me as if you lack attic ventilation... when the insulation
was blown in, it's possible they covered the soffit vents, if you have
A ridge vent will also help.
Light color shingles will help.
The purpose of the roof is to shed water, otherwise it should be as well
ventilated as possible while still keeping critters out.
Once you get the attic ventilated the upstairs temperatures should drop.
If they do not drop significantly then you may need to contact a HVAC
contractor to zone your house.
To efficively cool any space, whether the garage or attic, you need air
intak vents and air outlet vents. As Mac suggested, I would check
where the air is coming in. It's very common for insulation to be
blocking soffit vents. There are plastic baffles that are made that
you can staple to the rafters to keep the channel open. I'd also check
to see how big the soffit vents are or if they are blocked with paint.
You can install new or bigger ones.
For the outlet, I think a continuous ridge vent is the best way to go.
Doesn't use any power and provides even ventilation along the roof.
Adding additional insulation may help too. As for the A/C problem,
it's possible the system was designed poorly from the start. I've seen
lots of systems where there is inadequate ducting to the upstairs far
end reaches. An add on blower may help some, but may not solve the
problem entirely. Gettting the attic ventilated will help. Also check
the returns for upstairs. Sometimes they are undersized and enlarging
the grill opening will help. To really solve it may require either
installing more ducts or possibly a second ac for the upstairs.
Look at the links I posted. The soffits are also 'on the floor' so to
speak. It's not uncommon for for the soffits to get covered when
insulation is blown in. If air can't get in the attic, then air can't get
out of the attic. Think of it this way... you can't exhale if you don't
inhale first. Another thing that will happen is the attic will suck
conditioned air from your 2nd story through any leaks contributing to the
higher 2nd story temperature.
Before installing additional power vents, check the existing ventilation
to find out why it is failing, otherwise no amount of venting is going to
fix the problem. At some point you are going to have to hire a
professional who understands attic ventilation. The info you get here will
help prepare you to have an intelligent discussion with that professional
but hire the professional.
I hear what you're saying. I'm not sure I want to sift through a boat
load of blown in insulation looking for soffits. It seems to me (me
being ignorant of this stuff) that if a soffit is on the floor that
would mean the soffit is on the drywall which I call my ceiling from
my bedroom. If that assumption is correct then wouldn't I see the
soffit from my bedroom? If your answer is yes then I can assure you we
have no soffits on the floor of our attic.
Secondly I'm not saying anything is "failing". I'm saying it gets
really hot up there and that i'd like to get that hot air out. This is
Colorado. Homes here are built for winter more than they are for
summer. Our home is like toast in the winter. But summers continue to
get hotter and hotter (I think it is global warming brought on by
Greenpeace). I never said the home is failing. I said my garage is hot
and so is my attic.
Thanks for your suggestions.
This is an aside, but something you might want to consider.
When you install soffit vents and have blown insulation,
the insulation might very well block the necessary airspace
between the roof deck and double plate. I've seen this
frequently, including my own home. The problem is easier to
solve than you'd think. In my case, I used an air hose,
connected to my compressor, to blow the insulation back from
the airspace, but have also seen it done with a leaf blower.
In fact, it's not even necessary to remove the vent screen
in most instances.
You might be able to check from outside but it's much easier to check
fron inside because you can see whether the soffits are covered, check
during the day and look for light shining through.
I understand the confusion. Here is the link I posted that explained the
Although Jim's link is more detailed and may explain it better.
"Really hot" is subjective but if your attic and upstairs are 'too hot'
then the attic is failing to ventilate. The important thing is don't let
some guy talk you into additional roof vents if your soffits are blocked
or you don't have soffits. Clearing/installing soffits will help more
than additional vents (not saying that you won't need additional vents).
Not only will poor ventilation make you very uncomfortable it will
increase your energy costs and shorten the lifespan of your roof.
Best of luck.
This is true, but clearing a vent-path from the soffits to the peak
in a finished attic means destroying the finish work, and giving up
2 to 4 inches of space, minimum, when you move insulation from
between the rafters to below them. If mechanically forcing air
through the peak area works half as well, and costs 1/10th as much,
it's a good deal.
I didn't know his attic was finished. I think you are confusing two
different posters. There was a different post about venting a finished
Personally if I finished an attic I would finish it so there were no
spaces remaining and any small spaces that were remaining I would fill
You can't get something from nothing. He still has to have air inlets
otherwise the power vents will suck air from the living space unless the
living space is completely air tight and what are the odds of that.
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