attic fans
06-10-2008, 02:09 PM
#1
Make MyTL Great Again
Thread Starter
attic fans
I just bought a townhouse and with the weather being 95/100 recently it's really hot upstairs and terrible in the attic.
1 zone central ac unit
1 vent on the gable wall (exterior wall where roof comes to a point)
I believe I have soffit and ridge vents
Should I install an attic fan to blow through the existing gable vent? Cost savings form less ac usage?
1 zone central ac unit
1 vent on the gable wall (exterior wall where roof comes to a point)
I believe I have soffit and ridge vents
Should I install an attic fan to blow through the existing gable vent? Cost savings form less ac usage?
06-10-2008, 02:27 PM
#2
I now drive an accord....
Originally Posted by AdamNJ
I just bought a townhouse and with the weather being 95/100 recently it's really hot upstairs and terrible in the attic.
1 zone central ac unit
1 vent on the gable wall (exterior wall where roof comes to a point)
I believe I have soffit and ridge vents
Should I install an attic fan to blow through the existing gable vent? Cost savings form less ac usage?
1 zone central ac unit
1 vent on the gable wall (exterior wall where roof comes to a point)
I believe I have soffit and ridge vents
Should I install an attic fan to blow through the existing gable vent? Cost savings form less ac usage?
If you are thinking of a helper fan in the AC duct then that would help but install would be expensive.
I am in the same boat as you. I recently purchased a townhouse and I have single zone AC. Main floor is nice and cool, the family room downstairs is ice cold and the bedrooms and bathroom upstairs is on the warm side. My solution was to use a cheap oscillating fan for when I sleep. This has worked well for me on our 100 degree days. A freind is also in the same situation and put a window AC unit in the bedroom and it actually makes the central AC run less.
Edit: Ok so im stupid and realized that what I was referring to is a whole house fan. The attic fan should work for you
Last edited by spdy0001; 06-10-2008 at 02:31 PM.
06-10-2008, 02:38 PM
#3
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1) Are you sure it's a functioning vent on the gable wall. Most are just decorative
2) Have you contacted your HOA to see if you can do it? Most will not allow it
2) Have you contacted your HOA to see if you can do it? Most will not allow it
06-10-2008, 03:22 PM
#4
Make MyTL Great Again
Thread Starter
Originally Posted by NSXNEXT
1) Are you sure it's a functioning vent on the gable wall. Most are just decorative
2) Have you contacted your HOA to see if you can do it? Most will not allow it
2) Have you contacted your HOA to see if you can do it? Most will not allow it
2) no...but if it's inside the unit, no one is going to see the fan/it wouldn't disturb the outside appearance?
06-10-2008, 04:11 PM
#5
My friends... I am in the same boat. This heat wave in NJ is kicking our behinds.
You can actually feel the heat eminating from the attic. I need to install that fan ASAP.
Does anyone have any recommendations with fans? Are one of the fans from Lowes adequate? Also, what is the usual installation length of time and labor cost?
I am not good with heights and will need to hire a contractor.
You can actually feel the heat eminating from the attic. I need to install that fan ASAP.
Does anyone have any recommendations with fans? Are one of the fans from Lowes adequate? Also, what is the usual installation length of time and labor cost?
I am not good with heights and will need to hire a contractor.
06-10-2008, 04:14 PM
#6
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Cost to install depends on a few things, most notably access to electrical. The install is fairly simple if you have a functional vent. Otherwise you either have to cut a hole in the roof.
06-10-2008, 04:34 PM
#7
You need to be a little careful when adding attic fans to an attic that has a ridge vent and soffit vents. They're designed to work together to create circulation by drawing air through the soffit vents, up along the roof and out the ridge vent. Installing an attic fan can disrupt that flow and actually increase the temperature within the attic. Sounds to me that the real problem is that you have insufficient attic insulation. Another possibility is that insulation is blocking the flow of air from the soffit vents.
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06-11-2008, 01:27 AM
#8
05/5AT/Navi/ABP/Quartz
We get a string of 30, 100+ days every year but usually without your humidity. Attic insulation is #1 on the list especially if it is an older home. Wall insulation and dual pane windows also help but are more expensive. Portable or ceiling fans are a low cost quick fix.
Attic fans help remove trapped hot air and are a good idea. If it cools off at night or in the morning, a whole house fan is very useful. You turn off the air conditioning, open a few doors and windows then turn the fan on for a while. Cool air is drawn in from outside and the hot air in the house is drawn into the attic. Now that the house has cooled down, the A/C doesn't have to work as hard. I would and did hire a professional for the installation.
In my experience, the second story is always warmer unless the home is only a few years old and/or very well insulated.
Attic fans help remove trapped hot air and are a good idea. If it cools off at night or in the morning, a whole house fan is very useful. You turn off the air conditioning, open a few doors and windows then turn the fan on for a while. Cool air is drawn in from outside and the hot air in the house is drawn into the attic. Now that the house has cooled down, the A/C doesn't have to work as hard. I would and did hire a professional for the installation.
In my experience, the second story is always warmer unless the home is only a few years old and/or very well insulated.
06-11-2008, 10:44 AM
#9
Administrator Alumnus
First thing to check is if your attic is properly insulated. That's the first step before going the fan route, IMHO.
Myself, I'm way light on the insulation. So I'm going to add more before next winter. That is going to be a huge savings, I figure I'll get it back in just a couple of years. Not to mention some of it will come off my taxes as a credit.
Myself, I'm way light on the insulation. So I'm going to add more before next winter. That is going to be a huge savings, I figure I'll get it back in just a couple of years. Not to mention some of it will come off my taxes as a credit.
06-11-2008, 06:55 PM
#10
it's me, Alan Rickman.
This is what i'm looking at..
http://www.airscapefans.com/
Nice & quiet; they aren't designed to run 8137581375831 cfm but instead are designed to run quiet and efficiently for a longer period of time..
You can also get a remote so you won't even have to worry about wiring or cutting into the wall for a switch..
http://www.airscapefans.com/
Nice & quiet; they aren't designed to run 8137581375831 cfm but instead are designed to run quiet and efficiently for a longer period of time..
You can also get a remote so you won't even have to worry about wiring or cutting into the wall for a switch..
06-12-2008, 01:02 AM
#11
Trailingthrottleoversteer
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As an ex mechanical contractor, I have to tell ya that most of the time mechanical attic ventilation is not a good idea, and a waste of money.
Most of the home center fans sold are so dramatically oversized that they suck air thru every penetration and light fixture in your house ceiling...pulling the conditioned air with it. Second, they are usually so poorly made they fail within a couple of years of the motors being exposed to 130 degree + air. Oh, and they are noisy.
As others suggested, insulation is the key along with a really good natural convection path with eave, ridge and gable vents.
.
Most of the home center fans sold are so dramatically oversized that they suck air thru every penetration and light fixture in your house ceiling...pulling the conditioned air with it. Second, they are usually so poorly made they fail within a couple of years of the motors being exposed to 130 degree + air. Oh, and they are noisy.
As others suggested, insulation is the key along with a really good natural convection path with eave, ridge and gable vents.
.
06-12-2008, 02:36 PM
#13
Make MyTL Great Again
Thread Starter
Last night I checked and I do have a functioning vent. I could see out of the wholes and see the street lights/road. It has has some sort of screening inbetween the vent and the interior of the structure.
I'm going to get some plywood tomorrow and bring it up into the attic so that I will have a solid surface to stand on. Then I will look into a fan.
The house was built in 1996 and the insulation which is on the 'floor' of the attic looks good to me.
I'm going to get some plywood tomorrow and bring it up into the attic so that I will have a solid surface to stand on. Then I will look into a fan.
The house was built in 1996 and the insulation which is on the 'floor' of the attic looks good to me.
06-12-2008, 05:19 PM
#14
The sizzle in the Steak
Originally Posted by AdamNJ
Last night I checked and I do have a functioning vent. I could see out of the wholes and see the street lights/road. It has has some sort of screening inbetween the vent and the interior of the structure.
I'm going to get some plywood tomorrow and bring it up into the attic so that I will have a solid surface to stand on. Then I will look into a fan.
The house was built in 1996 and the insulation which is on the 'floor' of the attic looks good to me.
I'm going to get some plywood tomorrow and bring it up into the attic so that I will have a solid surface to stand on. Then I will look into a fan.
The house was built in 1996 and the insulation which is on the 'floor' of the attic looks good to me.
06-12-2008, 06:58 PM
#15
Bent = #1
Originally Posted by Scrib
First thing to check is if your attic is properly insulated. That's the first step before going the fan route, IMHO.
Myself, I'm way light on the insulation. So I'm going to add more before next winter. That is going to be a huge savings, I figure I'll get it back in just a couple of years. Not to mention some of it will come off my taxes as a credit.
Myself, I'm way light on the insulation. So I'm going to add more before next winter. That is going to be a huge savings, I figure I'll get it back in just a couple of years. Not to mention some of it will come off my taxes as a credit.
Can you explain this?
06-12-2008, 07:07 PM
#16
I miss my 03 CL-S :(
Make sure the gable vents open/close freely. You'll also need to be sure there's an electrical drop out there somewhere. The gable fans will come with about 2' max of wiring, so keep that in mind. I suggest you buy a thermostat switch for it. They'll have them right next to the gable fans at home depot. They're like $30. This will make the fan turn on when a temp hits a certain point and make the fan blow hot air out.
The installation is basically a handful of screws into something. Make sure there's a backing around the vent to mount the fan on. I think if there's no fan there now, and there never was, your biggest problem will be the electrical part.
Also, make sure the door to the attic is sealed pretty tight, or you'll lose $ with house air being blown out.
My roof-mounted attic fan just died the other day. I just bought a new motor and plan on installing it tomorrow morning. It definitely makes a few degrees difference in my second floor. Whether the cost of running the fan vs. the cost of having the AC a few degrees lower is economically smart, I don't know.
The installation is basically a handful of screws into something. Make sure there's a backing around the vent to mount the fan on. I think if there's no fan there now, and there never was, your biggest problem will be the electrical part.
Also, make sure the door to the attic is sealed pretty tight, or you'll lose $ with house air being blown out.
My roof-mounted attic fan just died the other day. I just bought a new motor and plan on installing it tomorrow morning. It definitely makes a few degrees difference in my second floor. Whether the cost of running the fan vs. the cost of having the AC a few degrees lower is economically smart, I don't know.
06-18-2008, 03:29 PM
#17
Racer
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Nobody mentioned flipping the butterfly levers in the HVAC ducts for summer.
Most rigid duct systems (fiberglass or sheet metal) in this latitude have butterflies off the main trunk that are supposed to be adjusted for heating and cooling seasons - look for levers to see if you have the option. Open the upstairs duct levers (turned in-line with the duct) and close off the downstairs ducts (turn levers to almost perpendicular to the duct).
The idea is to push more cold air up where the heat is in summer, and vice versa in winter. It evens out the temperature in the house dramatically.
Most rigid duct systems (fiberglass or sheet metal) in this latitude have butterflies off the main trunk that are supposed to be adjusted for heating and cooling seasons - look for levers to see if you have the option. Open the upstairs duct levers (turned in-line with the duct) and close off the downstairs ducts (turn levers to almost perpendicular to the duct).
The idea is to push more cold air up where the heat is in summer, and vice versa in winter. It evens out the temperature in the house dramatically.
06-19-2008, 12:01 PM
#18
I also noticed the second floor getting very hot during the heat wave a couple of weeks ago. I have single zone AC thinking about just putting in a room air conditioner in the master bedroom. Can one be installed in vinyl windows? The house is new we just moved in a few weeks ago.
06-19-2008, 12:11 PM
#19
I have an attic fan in my house...nothing like some of you are talking about. All this fan does is exchange the hotter air in the attic for the cooler air outside. Since the roof acts as a heat absorber, it really helps in bring the temperature of the attic down and helps keep the inside of the house cooler. It especially helps when it starts to cool down outside. I can get the temperature in my house down much faster than if heat lingered in the attic.
This type of attic fan doesn't touch the air inside the living space of the house.
This type of attic fan doesn't touch the air inside the living space of the house.
06-19-2008, 12:47 PM
#20
I now drive an accord....
Originally Posted by VTEC11
I also noticed the second floor getting very hot during the heat wave a couple of weeks ago. I have single zone AC thinking about just putting in a room air conditioner in the master bedroom. Can one be installed in vinyl windows? The house is new we just moved in a few weeks ago.
06-19-2008, 01:41 PM
#21
Make MyTL Great Again
Thread Starter
Originally Posted by thunder04
I have an attic fan in my house...nothing like some of you are talking about. All this fan does is exchange the hotter air in the attic for the cooler air outside. Since the roof acts as a heat absorber, it really helps in bring the temperature of the attic down and helps keep the inside of the house cooler. It especially helps when it starts to cool down outside. I can get the temperature in my house down much faster than if heat lingered in the attic.
This type of attic fan doesn't touch the air inside the living space of the house.
This type of attic fan doesn't touch the air inside the living space of the house.
06-20-2008, 12:24 AM
#22
Trailingthrottleoversteer
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Originally Posted by thunder04
I have an attic fan in my house...nothing like some of you are talking about. All this fan does is exchange the hotter air in the attic for the cooler air outside. Since the roof acts as a heat absorber, it really helps in bring the temperature of the attic down and helps keep the inside of the house cooler. It especially helps when it starts to cool down outside. I can get the temperature in my house down much faster than if heat lingered in the attic.
This type of attic fan doesn't touch the air inside the living space of the house.
This type of attic fan doesn't touch the air inside the living space of the house.
I have an attic fan, actually two gable mounted fans with barometric louvers. It's wired to a honeywell remote bulb thermostat set to 130 degrees and a variable speed fan controller set to about 500 CFM. It works great and took a lot of thought an planning when I was remodeling the house.
For the average homeowner - The only powered attic fans that actually make sense are the solar powered ones ($600) because the CFM exhausted is lower and the free electricity factor - payback is about 10 years... Most home center type powered attic fans are a poor investment and the electricity used to run them outweighs the minor cooling savings and air infiltration. Plus there are very few home center ventilators motors that will last in excess of a couple of years because of the constant exposure to high heat.
Better yet, the "turbine" type wind powered attic ventilators are even better and dont need electricity
http://www.fsec.ucf.edu/en/publicati...sec-gp-171-00/
found this on another site about venting:
>The rule with attic ventilation is 1 : 300 with a vapor barrier and 1 : 150 without a vapor barrier. So if you had insulation in the attic with a vapor barrier and the attic was 900 sq. ft., you would need 3 sq. ft. of free venting. If it was blown in insulation without a vapor barrier, you would need 6 sq. ft. of free venting. This is when you have an equal amount of square footage of high and low vents ( gable and soffit).
Your concern about attic fans is correct. The problem is not the fan but the over sizing of attic fans. Most attics can only handle about 1500 cfm of ventilation because of the vents. Your fan that you have probably moves about 2000 to 5000 cfm. In which case it could cause a problem with drawing air from the home and causing the problems you mentioned.
Properly sizing the fans is important because of this. You could increase the size of the vents but you're looking at more than doubling the amount. You're much better off putting in the proper size fan. The volume of air in the attic remains constant. So if the vents only allow 1500 cfm and the fan moves 2500 cfm, it will seek to get the air from somewhere, like the home. If the fan couldn't get the air from anywhere else, you would just burn out the fan.<
Your concern about attic fans is correct. The problem is not the fan but the over sizing of attic fans. Most attics can only handle about 1500 cfm of ventilation because of the vents. Your fan that you have probably moves about 2000 to 5000 cfm. In which case it could cause a problem with drawing air from the home and causing the problems you mentioned.
Properly sizing the fans is important because of this. You could increase the size of the vents but you're looking at more than doubling the amount. You're much better off putting in the proper size fan. The volume of air in the attic remains constant. So if the vents only allow 1500 cfm and the fan moves 2500 cfm, it will seek to get the air from somewhere, like the home. If the fan couldn't get the air from anywhere else, you would just burn out the fan.<
07-03-2008, 01:26 PM
#23
Originally Posted by NSXNEXT
1) Are you sure it's a functioning vent on the gable wall. Most are just decorative
2) Have you contacted your HOA to see if you can do it? Most will not allow it
2) Have you contacted your HOA to see if you can do it? Most will not allow it
I have an attic fan on my house and it's been working a lot recently, with the hot days here (I'm just a little bit further south than you).
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