Attic window open or shut?

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mwhitnee

Minister of Fire
Jun 10, 2015
586
Central Mass, USA
Just wondering, I have been keeping my small attic window open all year round. I open the top so rain cannot get in. I assume having it open during the warmer months is advantageous and closing it in the colder months is good too, but was just wondering what people do. Thanks in advance... :)
 
Is the insulation in the floor of the attic or between the rafters overhead?
But yes, generally the more air flow the better, especially if it's a cold attic (insulation in floor of attic).
 
From what I have learned with attics is that you should not have to have another vent besides the soffits. If the soffits aren't enough, then you're getting too much heat from the house through the floor of the attic or the soffits aren't working properly.

So I'd say, shut and see if that causes any issues.
 
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Insulation on the floor. Some cellulose insulation has gotten into the soffits so I'm going to try and clean that out pretty soon. It's very difficult to get to how the roof is sloped.

So I guess I'll start with that and then try shutting the window during the colder months and see how that works.
 
If your ridgeline is vented you should not have a side window open basically it will mess up the airflow. If your ridgeline is not vented then you want some airflow all year not just in the summer.
 
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If your attic floor is air sealed it shouldn't really matter, I'm guessing that if you lack air sealing and/or poor insulation it will contribute to the stack effect and suck conditioned air from the house. Someone with more knowledge might have a better answer.
 
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attic-ventilation.jpg

This is ultimately what you're trying to achieve year round from what you describe. I'm assuming that if your floor is insulated, as you look up you see the bottom of your roof plywood. You need to let that warm air out, ideally, you want your roof to be the same temperature as outside, (it'll never happen but getting as close as you can is good).
Some cold attics have a ridge vent, from the outside you would see your cap shingles are raised about an inch, this is your vent that they're sitting on, from the inside you should be able to see a little daylight sneaking in the ridge, if done right, and the plywood is at cut back at least an inch from the peak on both sides, this should provide sufficient air flow. IF the ridge isn't vented then you need gable vents or a roof vent like the one shown in the picture above. I have seen issues from gable vents being too small and restricting air flow, but never from them being too big. Sounds like your window is acting like a gable vent.
 
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This is ultimately what you're trying to achieve year round from what you describe. I'm assuming that if your floor is insulated, as you look up you see the bottom of your roof plywood. You need to let that warm air out, ideally, you want your roof to be the same temperature as outside, (it'll never happen but getting as close as you can is good).
Some cold attics have a ridge vent, from the outside you would see your cap shingles are raised about an inch, this is your vent that they're sitting on, from the inside you should be able to see a little daylight sneaking in the ridge, if done right, and the plywood is at cut back at least an inch from the peak on both sides, this should provide sufficient air flow. IF the ridge isn't vented then you need gable vents or a roof vent like the one shown in the picture above. I have seen issues from gable vents being too small and restricting air flow, but never from them being too big. Sounds like your window is acting like a gable vent.

I do not have a ridge vent, been up on my roof plenty of times due to chimney sweeping and there is none. I do know what that is and when I re-roofed my barn I had a nice one put in. Insulation on the floor, nothing but boards/plywood on the attic ceiling. I have vented soffits which might be slightly restricted due to a little cellulose getting in them (green arrows on previous pic, right?). But no gable vents. And I would say that the window would be acting as a gable vent for sure.

I have not really though about this too much, but still am unsure what the best thing is to do. Thanks for all of your input!
 
I do not have a ridge vent, been up on my roof plenty of times due to chimney sweeping and there is none. I do know what that is and when I re-roofed my barn I had a nice one put in. Insulation on the floor, nothing but boards/plywood on the attic ceiling. I have vented soffits which might be slightly restricted due to a little cellulose getting in them (green arrows on previous pic, right?). But no gable vents. And I would say that the window would be acting as a gable vent for sure.

I have not really though about this too much, but still am unsure what the best thing is to do. Thanks for all of your input!

Clear those soffit vents and add another window / gable vent at the other end. Excessive heat in the summer will shorten the life of your shingles, excessive heat in the winter will create ice build up. Work on sealing the living area from the attic (spray foam penetrations around lights, walls, etc...) Keep your heat and moisture in your living area and keep the air in the attic as close to outside temps as possible.

In the past we've used a stick with a nail or something on the end of it to expose any blocked up vents to the soffit, there's probably a short run on proper vent or rafter mate in there, if not, consider adding them so you can put the insulation back and still have air flow. Depending on the exterior, you can clean them from below too.
http://www.owenscorning.com/roofing/accessories/ventilation/raft-r-mate/
 
You could always add a ridge vent. So easy to do. It would likely cost you $100 and take about 2 hrs if you have never done it before.

Easiest part of roofing my house last year by far.
 
once i get a bunch of projects done, i need to put a roof vent in. We don't really have any air movement up there, AND it is not sealed very well. there are 2 small roof vents, but I think I could benefit from some new insulation, air sealing, and ventilation. Our access is actually from the outside, so now that I have my patio put back on, I can actually get up there and do some work.

I just got a new ceiling fan in the mail today, so I will have to get up there anyway....
 
i put the fan in last night, and it sure was warm up there in the attic.... I only have about 3 inches of black wool insulation, no soffits and 2 8" roof vents. I have quite a few holes and gaps that I noticed down in the corners that should probably be sealed, about 100000000 dead box elder beetles, some old wasp and hornets nests. Only a small section of the ceiling (that they redid in 1987) was air sealed, but is no longer effective since it has been poked, prodded and torn. we have the old chimney that runs through it, but it is not connected to anything anymore. At one point they had torn out some of the bricks and poorly installed a wood stove through the brick, but then never put it back.

20160721_080824.jpg
 
My rental attic has a ridge vent ,but no where for cool air to enter. After leaving the attic window open overnight it was amazing how cool it got in there. It even rained and the sill got wet but not the floor.
My home has a whole house fan installed in the upstairs hallway ceiling,when its cool at night that thing can suck the heat out of the house in record time. I have to open an attic window to vent the air,and there are some ridge vents too.
 
Last month I got my attic window installed by Canglow Windows and Doors (http://canglow.ca/windows/). I was thinking that I should open the attic window when it is cool outside and close them during warm days. But the service professionals said that I should shut the window in the early morning and open them later in the afternoon. On hearing this, i was a bit confused but when I tried it the result was awesome. The inside of my house is much more cooler than before.
 
You should open the window in late spring and close it in early fall. I cant think of a single reason tho close it all summer unless theres a big storm. it will vent heat out morning ,noon and night.
 
^^This^^ and make sure it's screened.
 
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