Attic Fans


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Old 03-04-16, 02:01 PM
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Attic Fans

I have a really bad ventillation problem in the upstairs of my house. I recently had a new roof put on my house and the roofing company concinced me that ridge vents would do a lot to solve the ventilation issue in my attic so I had him install them when he put the new roof on. They had very little or no impact. Several days ago, I had an air conditioning company out to give me an estimate on a new furnace and a/c system. The estimator told me that adding an attic fan like the one below would do a lot more than ridge vents toward solving the ventilation problem. This contradicts what the roofer told me.



Any thoughts?
 
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Old 03-04-16, 02:12 PM
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A ridge vent allows for a gentle flow of escaping heat.
The fan allows for faster flow of escaping heat.

Both rely on fresh air into the attic. If you don't have fresh air in..... you will not get outside air into the attic but will be drawing cooled air thru the walls from inside the house.

Do you have any kind of vents in your soffits ?

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Old 03-04-16, 03:12 PM
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That was my first thought, not enough or painted over soffit vents and any form of roof vents not going to work.
What type ridge vent did they install.
If it's the roll type there about useless.
Go up in the attic and look to make sure they cut the roofing felt and cut the sheathing back about 2" on each side. I've seen where they never cut the paper so it was useless.
If there is soffit vents make sure the insulation is not covering them, and baffles so the air flows not block.
What makes you think it's not working?
 
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Old 03-04-16, 03:50 PM
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You've got very good advice but I don't think most of it addresses your problem. There's different types of ventilation issues and differring solutions. Attic ventilation is often best served by a combination of ridge and soffit vents. Indoor ventilation, though, is a different issue and requires other solutions. One solution to upper level ventilation concerns may include a fan, but I can't tell.

So, please back up a second. Describe what you mean by a "really bad ventilation problem in the upstairs" including what you suspect may be the cause and when it occurs (for example, hot weather). Also, why do you think you need a new HVAC system?
 
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Old 03-05-16, 04:38 AM
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Also, explain why you got a new roof. Did you have a leak? If so was there water damage to wood or insulation? Mold?
 
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Old 03-05-16, 03:27 PM
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Describe what you mean by a "really bad ventilation problem
Let's say, on a spring or fall day where it gets up to 75 in the day and gets down in the 40's at night, it will get up to about 77 or so in the upstairs of the house and then when it cools down in the evenings, it stays warm upstairs and I end up having to turn the a/c on before I go to bed to get the temperature to come down from the upper 70's to the lower 70's even though it may only be 45 degrees outside. So, it takes a long time for the temperature inside to cool down on its own when it is no longer warm outside.

Also, why do you think you need a new HVAC system?

because the house is seveteen years old and still has the original, contractor grade a/c system and it also has a freon leak which I have replenished once already and I don't want to keep filling it with freon.
 
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Old 03-05-16, 03:32 PM
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explain why you got a new roof. Did you have a leak?
Again, the house is 17 years old with the original roof still in place. No leaks, yet, it's just a matter of time.
 
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Old 03-05-16, 04:40 PM
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Thanks for the information. I take it you have only one zone (That is to say, one thermostat.) and the thermostat is located on the first floor. I suspect the furnace is heating the entire house and much of the heat is ending up on the second floor - which is not unusual. I wouldn't view this as a ventilation issue because you don't want the warm air out, you want it more evenly distributed.

There's several things you can do. Since you're considering a new system, look into getting a separate unit (perhaps a heat pump) for upstairs. In that way you can regulate both floors independently.

Also, speak to your HVAC contractor about adjusting the portion of heat going to upstairs ducts. There are several cost effective ways to do this. It's also possible to redirect heat back downstairs.
 
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Old 03-05-16, 05:45 PM
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Tony.... I think you missed his point. He has excessive heat from the daytime that is not needed.

Excessive heat in the living space on the second floor can come from the attic. Usually it's due to lack of insulation between the attic and the living space. It can also be caused by the insulation in the outside walls on the second floor. If you do have an insulation issue and you add an attic exhaust fan without having a good source of fresh air into the attic.... you'll be drawing the cool air thru the second floor ceiling and into the attic.

I have basically the same issue at my house. Even with good airflow into the attic the second floor gets warm. I had my forced air heating system modified with central air. The return ducts on the second floor are all low in the wall as well as the registers which is how a heating system should be set up. It is not ideal for A/C and the second floor does not get good A/C flow.
 
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Old 03-06-16, 03:14 AM
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Yes, I agree. I'm viewing this from a tablet and couldn't see his location. (I've since gone to his profile and see he's in Georgia.) Lesson learned.

It sounds, though, like he's a good candidate for a fan.
 
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Old 03-06-16, 06:17 AM
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I take it you have only one zone (That is to say, one thermostat.) and the thermostat is located on the first floor.
I have dual zone, up and downstairs. The down stairs is fine
 
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Old 03-09-16, 05:35 AM
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Here is a good example of the problem. Yesterday it was about 74 degrees here. I didn't have my air conditioner on and it got up to about 76 upstairs. By 11pm, the temperature outside had dropped to 55 degrees, but the temperature in the upstairs was still 75. So, while the temperature had dropped almost 20 degrees outside, it only dropped 1 degree inside. So, of course, I turned the a/c on to get the temperature down to 72 where I like it when sleeping.
 
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Old 03-09-16, 07:17 AM
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Greg, I'm sorry I went astray earlier when I incorrectly assumed your home was in a colder climate. I'll try to redeem myself a little.

Heat travels by several means - for our purposes via convection and radiation.

Convection occurs in your home when warm air moves to a cooler area. Convection is typically addressed by insulation. But for you, insulation is working against you - stopping upper level warm air from escaping. You need something else to move the warm air out. This is where a whole-house fan would be a benefit.

Then there's radiant heat: the sun heating your home, in part from the attic. This is another way a fan would help you. Beyond that, you may benefit from a radiant barrier in your attic.
 
 

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