How much difference will ridge vents make ?

[mkepke]

Carrying on from my other thread about roofers, I thought to ask one of the companies about cutting in ridge-vents. It would be an incremental $250 all-in (labor, materials) to put ridge vents on my circa 1998 <3000 sq ft house.

Worst room in the house for heat loading is the bonus room, of course. It sits partially over conditioned space, partially over the garage and adjacent to a unconditioned attic space. The bonus room has soffit vents and a single gable vent. The adjacent attic has soffit vents and a single gable vent.

Should a good ridge vent noticeably reduce the heat-loading problem in this room ? (better venting in the rest of the house is just a bonus as far as I'm concerned).

-Mark

 

[junquecol]

I can tell you from working in attics with ridge vents, IMHO they don't work. I like a power vent fan. The concept of ridge vents is great, but the actual performance leaves a lot to be desired

 

[bobby g]

+1 to what Bruce said. I added two attic fans to our previous home and lowered to attic temperature by at least 20 degrees.

bobby g

 

[woodworker2000]

+1 for me also. My house was built with ridge vents (and a continuous sofitt vent) but I added a power vent fan after living in it for a couple of years. Like Bobby, I think the temperature in the attic dropped by 20 degrees after installing the fan.

 

[bwat]

Another ++ for the powered vents here. I live in a old home that was built in the teens, bricked in the 30s and was not properly vented. I added multiple roof vents and a single powered vent that has made an incredible difference. Ridge vents did nothing for me.

Also added a powered vent in the shop that really does a great job of pulling the hot air out!

 

[Glennbear]

This is one DIY question I can answer with authority since I have had experience with a ridge vent vs a powered attic vent. My house circa 2006 had a ridge vent and soffit vents when I moved in. Temperatures reached exceedingly high levels as shown by a remote thermometer I placed in the attic. I installed a powered roof vent and sealed the ridge vent to assure that air flow to the fan came through the entire space of the attic from the soffits and did not shortcut from the ridge vent. Thermometer readings after the change confirmed lower attic temperatures. :eusa_danc Lowering attic temperatures not only reduces heat migration to living spaces but also helps prolong roofing life since shingles stay a little cooler when they are not sitting atop a superheated attic space all day long. The only disadvantage to proper attic venting for a woodworker is that you will no longer will be living in a home with a built in lumber kiln. :rotflm:

 

[Mark Stewart]

Lowes and HD both carry a solar powered attic fan with thermostatic controlles for about $175 - 200 that is what I am saving my pennies for this year.

 

[Glennbear]

Lowes and HD both carry a solar powered attic fan with thermostatic controlles for about $175 - 200 that is what I am saving my pennies for this year.

I would caution you to research carefully before committing to a solar powered fan. When I looked into this before buying a conventional powered fan I found that the solar units were not all that effective. JMTCW. :wsmile:

 

[Charles Lent]

They work great, if you have good a way to let air into your attic as well.

When I first bought my home the heat in the attic was unbearable in the summertime, and the only attic ventilation was a rectangular vent at each end of the house up near the peak. I installed ridge vents and I wanted to add soffit vents to let air in, but the design of the house made this nearly impossible. Instead, I added some 8" thru-the-roof style vents near the lower edge of the roof (about 3' up) along the back side of the house. On a hot summer day the attic temperature is now within just a few degrees of whatever the outside temperature is. If I get near one of these lower vents while inside the attic the breeze of outside air coming through it is very noticeable, probably in the order of about 6-10 mph. The chimney effect of the warm air rising in the attic and exiting through the ridge vents causes the outside cooler air to be drawn in through the lower vents and no electricity is required for it to work. Most homes have attic vents to let the hot air out, but few have a way for outside air to enter to replace the hot air that's leaving. Without an open path for cool air to enter, the attic air cannot circulate no matter how many high vents or ridge vents you add.

Charley

 

[Gotcha6]

Homes that have ridge vents should typically have soffit ventilation as well for air intake. If the attic insulation is allowed to block circulation at the eaves it will not allow proper convection flow. That is the reason for insulation dams between rafters/trusses. Cooler attic temps may not always translate to lower cooling bills if the moving attic air pulls off any cooled air near the conditioned space.

 

[petebucy4638]

Carrying on from my other thread about roofers, I thought to ask one of the companies about cutting in ridge-vents. It would be an incremental $250 all-in (labor, materials) to put ridge vents on my circa 1998 <3000 sq ft house.

Worst room in the house for heat loading is the bonus room, of course. It sits partially over conditioned space, partially over the garage and adjacent to a unconditioned attic space. The bonus room has soffit vents and a single gable vent. The adjacent attic has soffit vents and a single gable vent.

Should a good ridge vent noticeably reduce the heat-loading problem in this room ? (better venting in the rest of the house is just a bonus as far as I'm concerned).

-Mark

Properly sized ridge vents with good soffit or other intake vents can do a good job of cooling an attic space. Adding a radiant barrier will make your attic even cooler. The problem is that it's very easy to short-circuit attic vents. Adding off ridge vents with ridge vents can induce the off ridge vents to become intakes instead of exhausts and that will cause the heat flow from the rest of the attic to collapse. Adding an off ridge power vent with an existing ridge vent can make the ridge vent act as an intake instead of as an exhaust vent too.

Roofers are usually not very good at designing a vent system for an attic. Many of them operate on the "more is better" principle. Adding a few vents on a home can be profitable for the roofer, it does not guarantee that you are going to have a cooler or dryer attic.

I'd recommend doing a little research on the net. There is quite a bit of information that can help you decide what is the best venting solution for your situation. Don't overlook a radiant barrier as part of the solution. They are fairly inexpensive, easily installed by the average home owner, and they really do work.

Bonus rooms over unconditioned garages are the toughest room in the home to heat and cool. The heat load that they take in through the floor, often uninsulated, is far worse than if that same floor were over a cool crawl space. These room usually take a big heat load from the roof and kneewall designs that are generally poorly insulated, and equally poorly vented. The fact that they are mostly enclosed in an attic that can easily reach 140 degrees does not help either.


Pete

 

[mquan01]

I installed a pair of these http://www.atticbreeze.net/zephyr_SFA.htm last year and my attic has not gotten above 90 since. I have a 2300 square foot ranch, so lots of roof on top. It's going to take a few years to recoup the cost. I also got a 33% tax credit.

 

[Charles Lent]

THINK GREEN.....when doing your attic venting.

Cool air rises when it is heated, just like the draft in a chimney. If you provide a way for fresh air to enter your attic at or near the bottom of your roof, it will rise when it is heated and it will exit through your high vents or ridge vents all by itself with no electricity required. Provide a large enough total air inlet and outlet area for your attic space and your attic will stay as cool as the outside air, without burning any electricity, and it will also be automatic.


Charley

 

[skeeter]

I was talking about adding a power vent to my current ridge vents (which don't seem to cool the attic properly) and have been told by a couple of people to be careful because by using both, there is a possibility of drawing in moisture through the ridge vents if the power vents are running while it's raining. If a power vent with a humidistat control would help, or if this is even a potential problem, I don't know but it's worth checking out.