2) I've also heard that it's ok (and preferable) to remove electric attic fans if you install a ridge vent since the ridge vent will allow heat to escape and the attic fans are just another place for water to find it's way in.
Any thoughts on these two subjects?
Thank you!
Being in a high-heat area (Houston) we considered light-colored shingles on a new roof. The roofing company reminded us they will get discolored from pollution and look just awful in a relatively short time.
Look at lighter-colored roofs in your area. Do they show dirt and soot and oily-film and mung and pigeon-droppings and cat footprints? Look at the bricks on your house; are they discolored from atmospheric crap?
The Pope has to power-wash the collonades at St Peter's square every so often to clean off the black. Do you want to be Pope?
Properly installed attic exhaust fans shouldn't allow rain. Even the teeniest electric fan will move magnitudes more air than a ridge vent.
Remember, too, you can't have too many soffit vents.
So, light colored tiles will get discolored over time and show more dirt so, from that perspective, it's better to go dark. "Energy efficiency" doesn't need to be considered or isn't worth considering?
Thanks.
Went light tan on new roof added ridge vent and had exisating gable end vents, attic temp still pretty hot 25 degrees above outside temp. Home inspector said powered vents needed but buyer backed out.
I would go light coloreed shingle add ridge vent and leave existing attic fans.........
you have them why remove them, and no they shouldnt leak!
I would say an attic fan in Houston could depressurize a home and cause an infiltration problem, pull humid air in through wall cavities. People in Houston like the inside temperatures cooler than the ambinet dewpoint so could be problematic set up.
Attic venting is a notthern concept to stop Ice dams, in the south the mentality is flushing out the heat.
Attic venting will enourage more heat transfer of heat from the top of the insulation to the air in the attic, and reduce some heat flow down through the insualtion and ceiling. Buit in a humid climate it also draws a lot of moisture into an attic and into a home.
Here's an interesting article on the subject. It concludes that ventilation has less of an impact on roof temperature than shingle color but still, color has a small impact.
Those both sound like baloney to me. Even with ridge vents, lighter colors can help hold down heat buildup. And a properly installed attic exhaust fan shouldn't cause water problems.
If energy efficiency is your main concern, you could live in a cave...
Put up light-colored shingles and within a year your roof may look like a dragon flew over and dumped partially-digested indigenous natives on it (dragons have notoriously inefficient digestive systems, much like Pandas - except dragons are carnivors).
Drive around. See what light-colored roofs look like in your neighborhood.
If there are any.
If not, ask yourself, "Why does no one put up a light-colored roof?"
I guess it depends on your neighborhood. Around here (Austin, Tx) there are plenty of light colored roofs, mine included.
Maybe we have fewer dragons flying over or something, but they seem to continue looking nice for years.
My very dark shingles looked good at 21 or 22 years when I was up on a ladder, but somehow by 23 or 24 years all of the ones on the south side of the roof had curled up tremendously, and the roof was leaking in a couple places.
I didn't get very light because they do get dirty, but I got medium brown instead of dark brown.
My townhouse, 700 square feet per floor, came with a full width ridge vent and full with soffitt vents (no interruptiosn) front and back. And the attic was hot as hell and so was the second floor, because it was near the attic. No one afaik put in 15 or 18 inches of fiberglass insulation in those days, but it did have 6. After I got the roof fan (I call it so no one will think I mean a "whole house" fan.) the temp of the second floor when I got home from work had dropped at least 10 degrees, and of the attic, maybe 30. It probably never gets more than
10 degrees hotter than the outside, when it used to get to 140 at least.I installed my fan myself, first time I done something like that, andit was easy to follow the instructions, and it has never leaked. However rain does land on the roof next to it and bounce into the screen around it (and maybe the wind blows it into the screen sometimes), where it further breaks up, and a mist sometimes falls on the floor below it. I have a plywood floor in the very center of the attic, and a few boxes, and the mist has never done any damage to them. They get a trifle wet and then it evaporates. I wouldn't even know about the mist if I hadn't been there hwen it was happening.
I did try to figure out how to have another screen as a barrier, but I couldn't think of anything and stopped trying, because it didn't cause any harm.
I would never give up my roof fan. The first summer I lived here, I would sleep in the basement, and go upstairs the next mornign to wash and get new clothes. It was too hot to go up there at all in the evening. With the fan installed, I could go up when I got home at
4:45 and I slept there every night.I put in two switches, and I turn off the fan in the fall and spring, so that the sunlight will heat the attic and that will heat the house. I may have lost some of that ability by getting the lighter colored roof, but my next door neighbor who got the same roof I did at the smae time, who uses AC, definitely saves money when the AC is on. Because I don't use AC, I guess the fan runs a bit less, but I don't think I save as much money as he does, because I wasn't spending as much to begin with.
I have had to replace the motor about 4 times in the last 22 years. The first time I ordered a new one from the fan maker, but after that I bought one at Electric Motor Repair in town. It might have been cheaper to buy a whole new fan and just use the motor. There is little consistency in how long they last, 3 to 8 years. I began to wonder if the rain was ruining them, but I don't think so anymore. There is no place to oil them, so that's not it.
It took 60 minuters to remove and replace the motor the first time, but now I think I can do it in 15 minutes, not counting turning off and on the cirbucit breaker.
Still, well worth it.
Great information - thank you.
The LOWER the roof and attic temp the longer the shingle life!
high temps wear out shingles fast.......... by dryoing them out
I'm finding quite a few articles stating that you shouldn't use a ridge vent with attic fans. One or the other. I really don't understand how it can hurt to have both since the idea to remove hot air from the attic. I;m thinking that the ridge vents will work under normal conditions and may, at times, keep the fans from even turning on by keeping the temp below their set range. But, on really hot days, the fans will go on and help out the ridge vent. Am I wrong?
Thanks. SB
The argument against both is that some of the air will short circuit. By that, I mean the fan will draw some cool outside air from the ridge vent and send it back out. With either alone, the path is from the soffits up, which is what you want. However, I think it's questionable how much of a factor this really is. I've never seen any real test data that showed anything. One technique would be to put the fan near an end and stop the ridge venting a few feet away.
The point of a ridge/soffit vent combination is to force the air to wash the entire undersurface of the roof. Among other things, this ensures that there aren't any pockets at the eaves or peak that are pooling hot air that doesn't move. If you put fans blowing air out somewhere else, then it's possible for all the air that comes in through the soffit vents to find it's way out through the fan exhaust, in which case, the ridge vents won't. (vent).
If you want more air circulation than the regular passive venting will provide, then I'd recommend laying drain tile down towards the soffits, and forcing air INTO them from intakes at the gable-ends.
I think that because I did it in 20 or less the last couple times. Without really rushing.
You're welcome. And of course you don't have to go on the roof to replace the motor. It woudln't even help.
Someone pointed out this possibility out at the start of last summer, and I meant to check it out.
Since he already has the ridge vent, if it is advisable, he could just plug up 3 or 4 feet on either side of the fan. With sheet metal or sheet vinyl or something. I think it looks better when the ridge vent extends across the whole house. The roofer used one piece, which I think comes rolled up.
But I would want to see for myself if it makes a difference. To suck air in through the ridge vent, it would have to fight the natural tendancy for hot air to be leaving, going up, through the vent.
This is the reason that there are shrouds around window insert fans, that just clear the blades. Otherwise one gets a spinning donut, that spins around a a circle in the center of the doughnut ring, if you get me. It's like taking a garter or a thicker circle of something flexible, and twisting part so the whole thing twists, while remaining circle shaped, if you get me. And with a fan, the air is just recirculated in that little area. But the question is, how much does that happen.
I looked into smoke pencils last night, to look for cold air leaks and they are far from cheap. One website said to use incense sticks to save money. I have one or two around here somewhere (They'r e probably overpriced to, but not as much as the smoke sticks. So I think I should get a small package, or mooch or buy less than a package from a hippie girl, if I can find one, and check out both my cold air leaks, and next summer my hot air currents.)
A little more on the subject. Now I still only have 6 inches of fiberglass, plus whatever cellulose was there when the previous owner bought the house new. And it has occurred to me that if I had 16" of fiberglass, maybe the second floor would not have gotten so hot before the roof fan was in place. (Although if it is 140 in the attic, and
70 in the house, I think even with 16 inches of insulation, some heat will get in, through the trap door or along edges, and straight through the 16 inches.But even then, the attic would be 140 and as they said, ruining the shingles and maybe the decking of the roof. Plus I'm able to go up in the attic for much of the summer much of the day. Maybe not the hottest days at 1 to 3PM but
So regardless of theoretical considerations of sucking air in through the ridge vent to the fan, or not evenly from the soffitts, the fact remains that the attic was much cooler, 30 or 40 degrees, and the 2nd floor of my house was much cooler, 10 degrees or more. I wish I had measured, maybe it was 20.
Even if the major air currents arent even in the attic, the temps even themselves out. You won't have an 90 degree breeze and a 130 degree hot spot right next to it. Bernouillis principle, and convection, and diffusion, and the temp of the attic is probably within 10 degrees almost everywhere.
I'm going to use the incense stick next summer, but even if I change nothing, I have a comfortable second floor. And remember that I only use the AC maybe 2 to 3 weeks during the summer, even in Baltimore. I like my windows open.
I doubt that's the rationale for not mixing the two, because an attic fan will lead to air velocities greater than those generated by even the best combination of ridge and soffit vents.
If you put fans blowing air out somewhere else,
How about a whole house fan ( in through windows, up through attic vents). Does the addition of soffit/ridge vents negate that?
Banty
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