Radiant Barrier and Attic Fan (Austin, El Campo: houses, allergies, living)

[janejanejanejanejane]

Anyone had either of these installed during the hotter months and notice a huge difference?

[G Grasshopper]

An attic fan really isn't for the hottest or coldest months. It is for the in-between months, like now, when you can open up the windows and the movement of air up through the attic will make you comfortable. When you get up into the 90s, or perhaps into the mid 80s, although the "old timers" made due with attic fans, most of us would need to move over to air conditioning. It is also great for cleaning out the air in the house after you burn something or for some reason you have a bad smell in the house (we can use our imaginations here.) Some people who have bad outdoor allergies would not appreciate this, as they wouldn't want the outdoor pollens coming in through the windows. We have an attic fan, and the people who lived here before us for 2 years never turned it on. For that matter, they never opened the windows. But we like open windows when it is a reasonable temperature, and we like the fan. So if you aren't sensitive to outside allergies, I think an attic fan is nice. But it is not a necessity. When we were looking for houses, our current house is the only one we looked at that had an attic fan, so it is not a common feature in recently built houses. There were other reasons that we chose this house - the attic fan was not a critical feature - but we do like it.

[OpenD]

Originally Posted by G Grasshopper

An attic fan really isn't for the hottest or coldest months.

Actually, it is, for the hottest. You're thinking of a whole-house fan, which circulates air through the house. But an attic fan does not circulate air through the house, it circulates air through the attic to cool it, because attic temperatures in a closed attic can easily exceed 120 degrees on a sunny day.

And yes, that can reduce A/C costs, as can a radiant barrier. It's all incremental. Every bit helps.

[10scoachrick]

Originally Posted by OpenD

Actually, it is, for the hottest. You're thinking of a whole-house fan, which circulates air through the house. But an attic fan does not circulate air through the house, it circulates air through the attic to cool it, because attic temperatures in a closed attic can easily exceed 120 degrees on a sunny day.

And yes, that can reduce A/C costs, as can a radiant barrier. It's all incremental. Every bit helps.

While I think it's important to know which 'attic fan' is being discussed, I can assure you that what we and our neighbors referred to as an 'attic fan' was indeed a 'whole house' fan(this was in the '60s and '70s). Would suck the drapes away from the windows!

'Whole house' fan in Austin??? Kind of like a convertible or sunroof...VERY enjoyable SOME days, darned near useless on others.

Attic exhaust fan in Austin??? Depends on the attic. If your attic only hits 110 degrees and it's 100 outside, the energy cost to run the fan might be more that it's worth. On the other hand, if your attic hits 130-140 degrees, getting that air out of there is likely a good idea. The most important barrier, IMO, is between the attic and the living space. IF you can keep the attic from heating up in the first place, all the better. I've not seen an 'add-on' radiant barrier that shows a decent ROI in the short term or long term. BUILD with a radiant barrier??? You bet! ADD a 'radiant' barrier...not so much. My .02 YMMV and all that.

[G Grasshopper]

Oops. I thought you were referring to a whole house fan. If you are talking about a fan that just vents your attic, you can cancel out my whole earlier post.

[10scoachrick]

Originally Posted by G Grasshopper

Oops. I thought you were referring to a whole house fan. If you are talking about a fan that just vents your attic, you can cancel out my whole earlier post.

As I mentioned in my earlier post, I grew up with an 'attic fan' that was just what you described...open the windows and feel the rush of air as the fan 'in the attic' pulled in hopefully cooler air and exhausted it out of the gable vent in the attic.

So, you may have hit the nail on the head with your response...depending on jane X 5's definition of attic fan.

[G Grasshopper]

Originally Posted by 10scoachrick

As I mentioned in my earlier post, I grew up with an 'attic fan' that was just what you described...open the windows and feel the rush of air as the fan 'in the attic' pulled in hopefully cooler air and exhausted it out of the gable vent in the attic.

So, you may have hit the nail on the head with your response...depending on jane X 5's definition of attic fan.

This change in definition probably tells you something about how old we are - or at least how old I am. The first "attic fan" I knew about was in my grandfather's house in El Campo, when I was a child, visiting family in probably the early 60s. I think the fan was installed much earlier, probably in the 30s.

[OpenD]

Interesting notes from Wikipedia...

Attic fan
From Wikipedia, the free encyclopedia
Not to be confused with whole-house fan.

Whole-house fan
From Wikipedia, the free encyclopedia
Whole-house fans were mainly popularized in the Southern United States through the 1950s-60s, as they were much cheaper and easier to find than air conditioners and still cooled relatively well.

[10scoachrick]

Originally Posted by G Grasshopper

This change in definition probably tells you something about how old we are - or at least how old I am. The first "attic fan" I knew about was in my grandfather's house in El Campo, when I was a child, visiting family in probably the early 60s. I think the fan was installed much earlier, probably in the 30s.

I'm right there with you...the house I grew up in and I come from the early '50s. I remember the swinging doors from the kitchen being pulled open by the attic fan(and I remember the sound of the louvers falling into 'closed' position when the fan shut down---goodness, that thing could move some air!).

[naterator]

The previous owner of our home had the house re-roofed after a big hail storm in 1995, but didn't bother with having any exhaust ventilation installed. We lived with it for years, until one time I went into the attic and it took my breath away. Made me very concerned.

So we had the spray-in radiant barrier, whirlybirds, 20" of insulation, and attic access covers installed. They all made a difference. Our attic access was in the hallway, so the access cover kept hot air from coming into the house. The raidant barrier and whirlybirds did make the attic a heck of a lot cooler. And it seems like the air conditioner doesn't have to run as long, or as hard, because the ductwork isn't cooking any more. Probably got another few years out of our old 13 SEER unit.

We noticed a slight decrease in our bills, but it was nowhere near the 30%+ you used to hear advertised on the radio. But the home is a lot more comfortable for about the same amount of money on utility bills, so from that perspective it was money well spent.