I learned something yesterday.
Soffit vents get dirty.
In fact they get so dirty they get clogged up.
A little background.
I have a 2 story Colonial house.
About 25 years old.
Outside dimensions are apx 25 x 45 feet.
As built, it hade four 16 x 4 soffit vents on both the front and back sides.
It also had 5 square “toadstool” style roof vents near the ridgeline on the back side of the house.
Two years ago we re-roofed and added ridge venting in addition to the 5 toadstools.
I was sure I was well vented.
For some reason, during the winter, SWMBO decided we needed more soffit vents.
I didn’t think so, but since I am a firm believer in air circulation and couldn’t see any harm, I said OK.
Besides, we had some minor soffit water damage and it would make a nice 2 in 1 job.
The existing soffit vents were common big box store ones so we just bought new ones all around in stead of trying to match the paint. They were less than $2.00 each.
Yesterday we tore off the old ones, cut 3 new holes between them, and put up the new vents. Now have a vent every 5 feet instead of every 10.
I was amazed at the condition of the old vents.
They were not just dirty, they were completely clogged up.
The best 2 may have been passing 25% of their designed air flow.
The louvers were so packed with stuff that it looked the felt material they make hats from.
How tightly it was packed was testimony to the amount of air velocity going through those vents.
Now, I do have a cottonwood tree in my front yard. And there are a few more in the neighborhood. If you have seen one, you know they are well named. When they go to seed the yards are full of “cotton.” Think of dandelion seeds on steroids.
That cotton, and of course, dandelion seeds, was what was packed into those louvers.
The lesson?
Soffit vents need maintaince.
Just because they are there doesn’t mean they are working.
At the least, they need a good pass with a whisk broom across the louvers in the fall.
If you can reach them a pass with a shop vac would help.
You could take them down a hose them off, but by then you should just replace them.
Like I said, they are cheap.
Soffit vents get dirty.
In fact they get so dirty they get clogged up.
A little background.
I have a 2 story Colonial house.
About 25 years old.
Outside dimensions are apx 25 x 45 feet.
As built, it hade four 16 x 4 soffit vents on both the front and back sides.
It also had 5 square “toadstool” style roof vents near the ridgeline on the back side of the house.
Two years ago we re-roofed and added ridge venting in addition to the 5 toadstools.
I was sure I was well vented.
For some reason, during the winter, SWMBO decided we needed more soffit vents.
I didn’t think so, but since I am a firm believer in air circulation and couldn’t see any harm, I said OK.
Besides, we had some minor soffit water damage and it would make a nice 2 in 1 job.
The existing soffit vents were common big box store ones so we just bought new ones all around in stead of trying to match the paint. They were less than $2.00 each.
Yesterday we tore off the old ones, cut 3 new holes between them, and put up the new vents. Now have a vent every 5 feet instead of every 10.
I was amazed at the condition of the old vents.
They were not just dirty, they were completely clogged up.
The best 2 may have been passing 25% of their designed air flow.
The louvers were so packed with stuff that it looked the felt material they make hats from.
How tightly it was packed was testimony to the amount of air velocity going through those vents.
Now, I do have a cottonwood tree in my front yard. And there are a few more in the neighborhood. If you have seen one, you know they are well named. When they go to seed the yards are full of “cotton.” Think of dandelion seeds on steroids.
That cotton, and of course, dandelion seeds, was what was packed into those louvers.
The lesson?
Soffit vents need maintaince.
Just because they are there doesn’t mean they are working.
At the least, they need a good pass with a whisk broom across the louvers in the fall.
If you can reach them a pass with a shop vac would help.
You could take them down a hose them off, but by then you should just replace them.
Like I said, they are cheap.

