Open or Close Attic Windows

edlincolnJune 23, 2014

My parents' house has two small windows in the attic that open.
Would it be better to keep them closed to keep out rain, or open to allow ventilation?

To provide background, the house has a hot unfinished attic with blown cellulose and fiberglass insulation beneath the floor and no insulation along the roof. I'm told there must be soffit vents and roof-line vents but I've never been able to find them. My parents can't get up there to close the windows before major storms and open them during heat waves. Very windy area.

This post was edited by edlincoln on Mon, Jun 23, 14 at 20:51

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All I can think of is bats and squirrels, and the poop that goes with them. You don't usually see open attic windows for a reason.

    Bookmark   June 23, 2014 at 7:28PM
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There is a screen. And while my parents have a lot of squirrels, there are no trees near these windows. I'm more concerned about bugs and rain.

    Bookmark   June 23, 2014 at 8:50PM
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I have a second story bedroom that used to be an attic. I leave one of the small windows open and have installed one of those small dual fan thermostat controlled window fans and they exhaust the hot air to the outside during the summer. Since the fan is blowing outward the rain does not come in.

    Bookmark   June 23, 2014 at 9:56PM
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We have a large full attic. 6 windows in all. 2 are ornamental and the other 4 are regular functioning windows. During the summer and most of Fall we keep 2 windows open for cross ventilation. It gets stifling and stale up there if we don't. The windows have screens. We do get bugs, flies in the Summer, ladybugs in the Fall. Small price to pay for being able to use the attic. If your parents are unable to close the windows when a storm approaches the fan is a good idea. NancyLouise

    Bookmark   June 24, 2014 at 6:46AM
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Replace the windows with a louvered, screened vent?

    Bookmark   June 24, 2014 at 9:09AM
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If air is allowed to enter it may bring moisture which should be a greater concern than temperature.

Most of the heat in the attic is from radiant energy from the underside of the roof that heats the floor without heating the air. It is the hot floor that then heats the air. Allowing air to enter will appear to lower the air temperature of the attic but it will do little to reduce cooling costs or extend the life of the roofing.

To keep the attic as dry as possible use ridge and soffit vents and close the windows. To reduce the temperature in the attic add insulation in the rafter bays.

    Bookmark   June 24, 2014 at 9:48AM
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We live in an un-airconditioned (ugh) 150-year old house with the same sort of attic as your parents'. What I use in the 2 end windows were in the attic when we bought the place 30 years ago, but they are similar to

I put them in the windows in June and remove in September, and don't have an issue with rain and insects. I think that these do help to moderate the temperature in the attic during the overnight hours, and heat buildup is certainly less than if the windows are kept closed.

We do not have soffit or ridge vents as the house is so old.

    Bookmark   July 4, 2014 at 8:36PM
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foodfriend's suggestion above sounds great. Hope it works for you.

Nice son being concerned and helpful!

    Bookmark   July 4, 2014 at 8:54PM
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foodfiend_gardener's suggestion is an excellent one. Thanks! Does it let enough air through? Only problem is it's too wide...the windows are 18 and 19 inches wide. Do you know where I can find smaller ones?

What we were using before was these weird thick screen/filter combo things, and I don't think they let in enough air. I'm including a link below to something like what we were using.

Also contemplating putting a tub near the windows to collect water that comes through.

Here is a link that might be useful: Window Filter.

    Bookmark   July 4, 2014 at 11:43PM
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The amount of cooling from a ventilated attic in the summer is negligible As long as you don't use a powered vent, which will just suck conditioned air from the home, at least protected open windows can't hurt.

Here is a link that might be useful: Understanding Attic Ventilation

    Bookmark   July 4, 2014 at 11:53PM
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So many of these articles seem to assume a scenario wildly different from any building I've ever lived in. Conditioned air? What's that? Sucking conditioned air out of the house isn't a concern. The house doesn't have central air. Nor does it have ductwork in the attic. Simple old house with no air conditioning, non--airtight attic, rudimentary ductwork in the basement.

    Bookmark   July 5, 2014 at 12:06AM
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Those are narrow windows... the ones that we found in the attic after we bought our old home fit perfectly so I didn't have to look for any. They let just a little air in, but no rain or insects. Somebody, somewhere must make the size you need.

I clicked on the link and this also came up on the page:

For $14, could you buy one and try (or have some handy-type person try) to alter it? Or call the manufacturer and ask if they offer them in a smaller size? Would probably be more expensive, though.

After 30 years, I still think that using these in the heat of summer does help keep our upstairs a little more tolerable (although we did buy a room a/c unit for our bedroom one year when the upstairs temp constantly went over 85). And it can't hurt to keep minimal air flow going in that attic area.

The tub under the windows would help with rain on the floor, but I think that eventually the windowsill/ bottom of frame would rot. At that point, I would opt to keep the windows closed.

Good luck!

    Bookmark   July 5, 2014 at 9:14AM
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You need to understand that a roof heated by the sun with no insulation in the rafter bays will radiate (infra red) heat to the floor of the attic without heating the air. Then the hot floor heats the air. There is little point in trying to reduce the temperature of the air if it doesn't cool the floor. Don't confuse cause with effect.

If you want to reduce the heat gain from a hot attic floor, the first thing to do is add a radiant barrier (aluminum foil) to the floor surface or to the bottom of the rafters. The next step would be to add insulation to the rafter bays.

If you are not trying to reduce heat gain then adding louvers and screens to attic windows will help reduce moisture in the attic if the outside air is drier than the attic air but try not to confuse moisture control with energy conservation.

    Bookmark   July 8, 2014 at 10:07PM
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The goal is to cool the house in the summer. Wouldn't the floor gradually lose heat to the air just above it? And wouldn't it lose heat faster to moving cooler air from outside then hot stagnant air? And I doubt the attic in an old house is air tight...wouldn't hot air from the attic leak into the house?

I've thought of radiant barriers. I suspect there is is one beneath the floor. I'm a little nervous about putting one on the floor because people would have to walk on it. If you put one on the ceiling, would that promote roof overheating or mold?

Everyone starts out saying things that make sense, then throw in something that makes me think they are assuming the house has central air...

Anyway, would the air in the house be more or less humid then the outside air? I'm assuming more, since moisture gets added every time someone uses a dishwasher or showers.

This post was edited by edlincoln on Wed, Jul 9, 14 at 0:07

    Bookmark   July 8, 2014 at 11:57PM
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