OT--Attic Ventilation

Jiles · Jun 12, 2015

As some may know, I posted a problem with powered attic vent motors.
I have three roof mounted powered vent fans. Two motors went bad on the same day? I removed the motors and found they were not burned and no smell.
They had an external mounted capacitor so I removed the known good one, and neither would run.
Now, I am faced with buying three motors (might as well replace all). Cost will be close to $200.00.
I am beginning to wonder if it is worth the cost. A few years ago, in another home, I replaced the roofing in which there were no vents in the attic. A roofer advised me to just put three "Pancakes" for vents. He also said he did not recommend the turbines because they have cheap bearings and would spin while setting in grass or on driveway!
Just wish I could find an actual comparison test as to how efficient each type ventilator is.

Prawn Farmer · Jun 12, 2015

Having been in the lumber and building business for 30 years, I was always a huge proponent of any type of ventilation that wasn't mechanical or electrical.No maintenance, no moving parts, no electricity, no climbing on roof every couple of years. Ridge-vent and under soffit vents are my first choices and then maybe the Lomanco 750 type vents as an alternative. Your lumberyard can tell you what "free area" of ventilation is needed if you'll bring your attic area with you.

Janicholson · Jun 13, 2015

A different solution is a whole house fan. Mine blows into the attic from the second story hall. the air escapes through gable vents. the fan is a lenox forced air squirrel cage with 3 speeds. The speeds are switched from a wall plate in the hall. This system saves radically on AC and never lets the attic/get hot. In the evenings it makes an incoming breeze in every open window. The bearings are real and serviceable. Jim

FBH44 · Jun 13, 2015

spinning while just sitting there is truly excellent.
You want cross-ventilation, across all sides of the attic.

Traditional Farmer · Jun 13, 2015

My uncle years ago had a set up like you're describing,they'd turn the fan on and leave all the windows closed except for 2 in the basement.The fan would pull the cool air from the basement thru the rest of the house and it was always pretty cool even on very hot days.

Leroy · Jun 13, 2015

I have learned the best is no venilation here in Ohio. Years ago built addition to house and put in the ridge type vents.. Supposed to keep out snow, right? First big snow the attick was filled with snow that came in that vent. Took it out and closed up roof as I orignally planed on and no problem for years afterward. But you think that is easy cleaning out that snow off of the top of bat insulation. If I was buying a house that is one of the first things I would be checking for and if they were not gotten rid of the house would be off my look at list. If you are in hot climate with no snow then vents might be OK. Have none where I am living and in last over a hunderd years there has been no problem without them.

WGM · Jun 13, 2015

I agree. Ridge ventilation is the only way to go.

WGM · Jun 13, 2015

The only way ridge vents would allow snow in the attack is if it was installed wrong.

Bonnan · Jun 13, 2015

I have and do the same as Janic.... My Dayton whole house fan has been for 40 years; added ridge vent aboout 20 years ago and works even better. Leroy is apparently is misdirected in blaming the "vent" as a solution. His install had to be bad.

BAnNC · Jun 13, 2015

Shingle over type ridge vent and continuous soffitt vents allow continuous air and moisture exchange keeping the attic space considerably cooler and venting moisture that causes problems out of the house. I know we don't have as much snow as some in more northern climates but never had any problems.

Blackhole49 · Jun 13, 2015

Agree with that!! I've had ridge vents in SE MI for 25 years. Never had snow in the attic. I've had a 24" attic (whole house) fan for 15 years. It will clear the table for you on the high setting.

Prawn Farmer · Jun 13, 2015

Leroy, although the perforations are on the underneath side of ridge vents, I suppose a hard blowing snow or rain could be forced up and underneath just as it could with gable vents, whirlybirds etc. and I suspect that is why, in high snow fall areas, the use of gable vents has always been the norm.

You said: "Have none where I am living and in last over a hundred years there has been no problem without them."

If the house is over 100 years old, assuming you haven't replaced windows and siding, it more than likely isn't as "tight" as today's homes. Back then they didn't have all the showers, washing machines, dishwashers, mother-in-law's heavy breathing putting as much moisture into the house - although some of my ancestors probably kept chickens and a goat in the house, but that's a different story. Potential condensation problems would defiantly be a flag to most home buyers and inspectors today as there is an increased chance for mold growth in the walls and attic ceiling. Your choice - your house.

Steve@Advance · Jun 13, 2015

Since the power vents are already in place, the quickest and easiest fix would be to replace the motors. I've
put a few in, had the same result, short motor life. These were the DIY models from HD or Lowes.

When I replaced the motor, I went with an aftermarket motor that apparently was better quality. Haven't had
to replace them since. One also had to have a new thermostat, again I went with an industrial duty (because I
already had it) thermostat that will last forever.

If the rest of the vent is still in good condition, I would just replace the motors, see what happens.

Jiles · Jun 13, 2015

(quoted from post at 17:14:34 06/13/15) Since the power vents are already in place, the quickest and easiest fix would be to replace the motors. I've
put a few in, had the same result, short motor life. These were the DIY models from HD or Lowes.

When I replaced the motor, I went with an aftermarket motor that apparently was better quality. Haven't had
to replace them since. One also had to have a new thermostat, again I went with an industrial duty (because I
already had it) thermostat that will last forever.

If the rest of the vent is still in good condition, I would just replace the motors, see what happens.

Thanks Steve, that's the kind of reply I am asking for. It would cost a sizable amount to install ridge vents, especially on an eight year old roof.
I have found Broan replacement motors, made in the USA. They are about $5.00 higher then Communist made ones! !
Made in USA means a lot to me--if they actually are. I will see.

Jiles · Jun 13, 2015

(quoted from post at 11:32:20 06/13/15) spinning while just sitting there is truly excellent.
You want cross-ventilation, across all sides of the attic.

He made that statement because the wind was causing them to turn. He said most people think hot air escaping from the attic is spinning them.

cool hand · Jun 13, 2015

Ridge vents without a spun glass filter in them (some of the early ones) will allow blowing snow to enter and fall into the attic.

Texasmark1 · Jun 13, 2015

Problem I had with turbines initially was that I figured that I didn't want ventilation in the winter so I tied a plastic bag around them.
Wrong! Froze up the bearings so next winter I made a plug for the hole out of foam and let her spin. Once a year I'd take the top
off and grease the bearings. One day I stood under one with my head in the hole and they really move a lot of air. Another time we
were having a storm, wind blowing and raining like crazy. Stuck my head up there again and just the slightest of mist could I feel
with the air rushing past me.

140F is not uncommon in an attic and can be worse if roofing is a dark color or no vents. You are trying to maintain 70 something
degrees for personal comfort on the other side of your attic insulation.

Insulation merely retards the flow of heat from one location to another....Heat, AC, and REf. 101. It does not prevent the recipient
from becoming the ultimate temperature of the sender. Therefore to come out with a lower average "sending" temp, you want the
attic to be as cool as possible for the effort extended. Turbines, unlike power attic ventilators, are not only inexpensive, and last for
10's of years, but require no fuel to power them and are highly efficient in moving large quantities of air.

guido · Jun 13, 2015

Hello JIles,

A power ventilator that can move 1050CFM's is worth about 6.000BTU's if I remember correctly. It is also important that the intake air is matched with the units. An air condition and refrigeration store can probably tell you the exact air intake requirements. Sometimes the box from the power unit will also state the air intake requirements. May be you can look when you go get the them. Around here they are set at 85 degrees F* You may also find that the new one will have a dew/moisture thermostat as well.

Guido.

Geo-TH,In · Jun 13, 2015

Guido,
I use 1200 cfm's in house and 1500 cfm's in barn. The 1500 also has a humidistat and thermostat fan switch.

I'm a believer on them, obviously some are not. I've installed my first one in 1992. Same motor, just clean and oil as needed. It's possible motors today are glued or welded together and can't come apart.

One time I had a coon get on roof and tried to bend cover to gain access to attic.

I think my fans use less than 3 amps, which costs me about $.03/hour. 10 hours a day, $.30, about $10 a month. I think it's well worth the money. My central AC isn't used much.

I'me also a beliver in eve vents and regular roof vents, can't have too many.

Leroy · Jun 13, 2015

Only thing was just a window type screen to keep things out more for bugs than anything else. And was installed according to directions.

Leroy · Jun 13, 2015

The house has been redone with new windows, double pane with storm windows. The old siding covered over with OSB board, bat insulation in walls, blown in in attic.

OT--Attic Ventilation

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