This month, I installed some ventilation in the basement.
(not really 20 CFM)
http://www.suncourt.com/Images/Radon-airflow-chart.jpg
(My wife loves it when I drill 3.5" holes in the house)..
The blower is set up to run between the hours of 10AM & 8PM.
Radon Fan Instructions
The air intake is about 6" from the basement floor.
The output is outdoors, on a wall in front of the house.
My goal was to increase fresh air flow in the basement.
Now it smells nicer, not musky like it has been.
Also, I want to warm up the basement using warmer outside air.
During the last few days, I've noticed the temperature has gone up a few degrees.
(That might be the normal heat gain, since it's been up in the 80s outdoors).
Since I didn't install this unit as a radon abatement setup (sucking air from below the floor slab),
and well away from our
only large source of radon (from a sealed sump hole),
I didn't expect much (if any) drop in the radon readings at the sealed sump.
I wondered of the lowered pressure in the basement would pull up even more radon gas..
This week, we've been having a lot of rainy weather, which has raised the water table.
The pumps started running, and I had to un-seal the Radon hole!
After placing a pump in that hole, I re-set the Radon monitors. (ave was 4.2)
I know from experience, that we always get a jump in radon during flooding.
Even a small upward change in the water table always causes more radon.
Now that the hole was un-sealed, I was expecting to see higher readings.
But, they are now lower than we've ever seen. (Water blocking the gas now?)
I had hoped the fresh air setup might help the radon problem.
Never figured they would be this low with the sump unsealed.
After the rainy season is over, I plan to remove that pump and re-seal the sump.
It will be interesting to see if the level drops even lower.
~~~~
The main air-input to the basement is coming down the basement stairs,
from the attic pull-down stairs, which is open about 6". (isolated by a door from the main house).
I was hoping this will help keep the attic a bit cooler this summer.
(while warming up the basement a bit).
But, I'm not sure the blower can fight the chimney effect in the attic.
The slight air flow I can feel coming down the stairs, doesn't feel warm at all.
This is on days when it's 120F or more in the peak of the attic..
Perhaps the air nearer the attic floor isn't so hot..
I'll have get up there when the sun comes back and measure the attic floor heat.