Removing Hot Air from Vaulted Ceiling

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Hi,
I have a two story house with vaulted ceilings throughout. I had AC put in last year, but the upstairs doesn't really cool down. The front of the house has the biggest windows, and is West Facing, so it gets all of the afternoon sun. Last year, I also replaced all of these windows with much more efficient windows.
However, I can't get it below 80 degrees upstairs. And this can often be when its cooler outside.
In examining my options, I noticed that I have NO vents on my roof. I have all vaulted ceilings, so I don't have an attic. I do have some soffit venting on either side of the slope of my roof.
Can I put turbine vents on the roof? Will this make a difference in temperature for those upstairs rooms if I can cool the space between the ceiling joists and the rafters? Again I have NO ATTIC.
Really, what I'm looking for is a way of removing that hot air from the vaulted ceilings in the summer.
Any suggestions? Turbine vents appear to be an easy solution. Will cooling the space between the roof and the ceiling help in cooling the room below it?
- Thanks in advance,
Todd
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Ceiling fans will work well for vaulted ceiling. With a remote

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Todd wrote:

Maybe. Soffitt venting might be useful, _if_ it's of adequate inlet area _and_ air coming in there can move up inside the roof deck and escape somewhere. ,
Insulation between ceiling and roof deck could block airflow, unless spacers were installed between insulation and roof deck. You mention nothing about this.
Ridge vent could work, and is simple, elegant solution, depending on stuff mentioned above. Thermostatically-controlled fan(s) with mushroom-looking enclosure would work.
Ask locally, and/or visit big-box.
J
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snipped-for-privacy@sme-online.com wrote:

But how is it that venting the this space will help remove the heat from the ROOM below it? This is what I don't get. I understand venting the soffit, but I don't know how that will allow the heat in the room below (with the vaulted ceiling) to cool down.
Any thoughts on this?
- Thanks,
Todd
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First you have to realize how a vaulted ceiling is constructed. Essentially you have spaces that are seperate channels, running from soffit to peak of the roof. If you put in a turbine type vent, or a simple box vent, all that is going to vent is the one channel. You'd have to put one in between every rafter to vent the whole thing.
A ridge vent is the correct solution. However, the next thing you are up against is how much insulation was put in and how it was installed. If it's too thick there may not be room for air to flow above it. If it's pushed up over the soffit vents, air can't get in. The right way for this to be done is to use plastic baffles that go in above the insulation, beneath the decking to keep the channel open. Unfortunately, you have no way of knowing how yours was done.
You don't have anything to lose by adding a ridge vent. It can't hurt and if air can flow, it will help a lot.
To answer your other question, this can help reduce your room temp because it helps decrease the temps directly above the insulation. However, if it's 80 deg, adding a ridge vent ain't likely to cure that. I'd get the ace AC guys that did the install back and see what they have to say. Did they install sufficient returns up high?
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I don't think that my vaulted ceiling is contructed in the way that you suggest. I think that there aren't seperate channels, but rather an area in between the rafters and the ceiling joists. I don't think they are conected to each other, which would, as you suggest, create seperate channels.
I could be wrong, and I'll have to take a look, but snipped-for-privacy@optonline.net wrote:

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Todd wrote:

Having the roof decking on one side of the rafters and the the ceiling on the other is the simplest, cheapest and direct way of creating a vaulted ceiling and it gives maximum height. If yours is done with seperate rafters for the roof and ceiling joists with a space in between, then you could ventilate that by means other than a ridge vent, like your turbine idea. However, I still think in that case, a ridge vent is still the way to go.
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I'm guessing that you have a n older house made before A/C or otherwise doesn't have proper ducting for A/C. In order to get rid of the hot air, you need a return air in an area where it's hot. If your lowest return air grill in near the bottom of an upper floow (i.e. in the floor itself or low on the wall) then you will need a return air placed higher to draw in the hot air instead or recirculating the already cooled air.
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The house wasn't built for A/C, it was built for heating. It does have central heating, so added A/C wasn't a big deal since all of the duct work was there. However,
a.) the ducts upstairs aren't as wide, to prevent TOO MUCH heat from getting to the upstairs during the winter
b.) the return air upstaris was located at the bottom of a wall.
I put a second return air register as high as I could go right over the existing return register, just 8 feet higher.
The problem is that the only air return occurs in the hallway, and not in my bedrooms surrounding the hallway. And the bedrooms surrounding the hallway have vaulted ceilings as well.
Its would be great if there was a way to get the hot air in the bedrooms into the hallway and down the air return.
But still, i figured that venting the space between the ceiling and the roof would better cool the room. I dunno.
- Todd
snipped-for-privacy@gmail.com wrote:

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Todd wrote:

Hi, Todd.
How do you think the interior air (mostly) gets heated? Unless you didn't tell us about the forge/smelter you're running in there, I'll wager that the majority is coming from above. And you want to stop that, by diverting it harmlessly (read: avoid roasting roof.)
Thus, if you dissipate heat from roof (see my previous about ridge ventc, etc. too) it won't heat the innards. Infrared transmission can move some serious energy.
You still haven't told us anything about what's between the ceiling and the roof deck. Please investigate & report. You need to know this.
Once you control unwanted entry, then it makes sense to throw $ at reducing the rest.
J
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Todd wrote:

What did the contractor's heat gain calculation say that you needed in BTU to cool the house, and how big a system did they put in? Is it zoned?
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Todd wrote:

Get a ladder.
Is the ceiling significantly hotter than the air around it? If so, the heat in the air is coming from the ceiling.
If not, the heated air is coming from the rest of the house (heat rises).
Also, think trees.
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Thats a good thought. I will check with a ladder.
I imagine that its a combo of things -> the heat rising, AND the roof collecting heat.
HeyBub wrote:

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wrote:

Exactly. A couple of points. 1. If at all possible, leave the heated air in your vaulted ceilings. No fans are anything to disturb the hot air. It is where it should stay. The temp below can be 5 degrees cooler if you don't disturb it.
2. Your house should have been built with ridge vents all over your roof. And there should a channel for the air to travel up from soffit to ridge vent. Lowe's sells them. And of course lots of insulation directly behind your cathederal ceiling. When you reroof, fix it. Or else rip out the sheetrock and fix it when you get fed up with high energy bills and hot house.
3. You definitely need two separate units until you fix the problems.

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That's what I thought. The fans are good in the winter, to blow the hot air from the top of the room down to where you are, but in the summer doing that just makes one hotter. Right?
There is a slight breeze from slow ceiling fans, but a better breeze is created by a table fan that blows low altitude cool air on you, rather than ceiling level hot air.
Of course the hot air will get cooled by the AC, but why bother, when it can just stay in the upper altitudes of the room, right?
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mm wrote:

Wrong. Ceiling fans blowing downward, with the AC running is always going to feel cooler. Your AC vents are either located high up on the wall or in the ceiling. So when the AC is blowing, the cool air is going to blow above the fan creating a "cool breeze" effect. Fans on vaulted ceilings should hang about 8ft from the floor.

With a good fan you get much more than a slight breeze. I suggest "The Hunter Original" 56" fan for the larger rooms.
I've owned 3 houses with vaulted ceilings and the "Hunter Original" is the only fans I have ever used in the larger rooms.
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On 29 Jul 2006 00:43:26 -0700, snipped-for-privacy@msn.com wrote:

So you like to take that hot air trapped in the vaulted ceiling and spread it around eh? Big stupid mistake, but to each his own.
Ps: my electric bill is less than yours.
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JimL wrote:

If you have hot air "trapped" in your ceiling that is 5 degrees warmer than the room temperature, than you, my friend, have some insulation problems. Or worse.

http://www.progress-energy.com/aboutenergy/learningctr/savingtips/ceilingfans.asp
How Ceiling Fans Save Energy Fans used to supplement air conditioning save energy by permitting a higher thermostat setting. Air movement from the fan evaporates moisture on the skin and makes a person feel cooler. With this cooling effect, most people can raise their thermostat three to four degrees and feel just as comfortable. And that can mean savings of around 25 percent on your cooling costs. For every degree you raise the air conditioning thermostat, you can save 7 percent to 10 percent on cooling costs. However, there are no energy savings if you use a ceiling fan and do not raise the air conditioning thermostat.
http://www.consumerenergycenter.org/tips/business_summer.html
Install ceiling fans - they make it feel at least four degrees cooler during the summer.
http://www.energystar.gov/index.cfm?c=products.es_at_home_tips
Ceiling Fan w/ lighting: Ceiling fans can provide more than comfort. Depending on when and how you operate them, they can also help you save on your energy bills. In summer, run the blades counter-clockwise (downward) to cool more efficiently. On hotter days, dialing up the thermostat by only 2 degrees and using your ceiling fan can lower air conditioning costs by almost 15% over the course of the cooling season. Use ENERGY STAR qualified CFLs in the ceiling fan light fixture for cooler running light bulbs and more energy savings. And remember: Ceiling fans cool only people, not the room, so when you leave the room turn the ceiling fan off.
http://phoenix.about.com/od/homesandrentals/qt/fans.htm
Why a Ceiling Fan Just the movement of the air inside the house in the summer may be enough to lower that thermostat for a couple of degrees, and save you money on those summertime electric bills. You might save between 10% and 40%! That means that the ceiling fans could easily pay for themselves over just one or two summers in hot climates. Ceiling fans don't lower the temperature in the room, they just provide a breeze that can make you feel at least 5 cooler. Make sure the ceiling fan blades are rotating counter-clockwise for a cooling effect. That's the direction most ceiling fans need to move to get a downdraft.
http://www.fsec.ucf.edu/Pubs/energynotes/en-13.htm
Conclusion In the hot, humid Southeast, fans can make people more comfortable and reduce air conditioning costs. They can improve interior ventilation and allow thermostat settings to be raised without sacrificing comfort. The use of ceiling fans and oscillating fans are effective cooling measures that should be considered and implemented where feasible by any homeowner in the southeast.
http://www.hunterfaninternational.com/support/fan-faq.php?origx=38#6
6. How do fans cool the room - do they actually lower the temperature? A ceiling fan cools by creating a wind chill effect; it does not lower the room temperature. Wind chill effect makes you feel cooler by accelerating the evaporation of perspiration on your skin. It is the feeling you get when you open the window in a moving car. If you have a ceiling fan in a room whose temperature is 27 degrees Celcius, running the fan can create a wind chill effect that makes you feel as if the temperature is 23 degrees Celcius. When used in conjunction with an air conditioner, a ceiling fan can lower energy costs, because you can set the thermostat of your air conditioner at a higher temperature.
7. Can the fan be used in the winter for any beneficial purpose? A ceiling fan can help lower energy consumption in the winter by up to 10%. The temperature of the air in a heated room varies in layers; the air near the ceiling is warmer than the air near the floor, because warm air rises. A ceiling fan can help push the warmer air that is trapped near the ceiling back down into the room, thus de-stratifying the layers of warm air. As a result, the warm air is circulated where it is needed, and the heating system does not overwork to warm the room. To properly de-stratify a warmed room, the ceiling fan should be run in a clockwise direction. This pushes the air up against the ceilings and down the walls, to gently re-circulate the warm air without creating a cooling wind chill effect.

My monthly gas bill for my car is less than yours. What kind of dumbass comment is that?
Nevermind, I figured it out.
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Or an IR thermometer.

I guess we need the ladder to measure the air temp. Aim the thermometer at a piece of paper...
Nick
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On 28 Jul 2006 05:34:07 -0400, snipped-for-privacy@ece.villanova.edu wrote:

Why paper? Do you get false readings otherwise?
What should I beware of?
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