About 2 years ago, I had the attic insulated with blown insulation and a new attic fan installed (controls humidity as well). After installing a new water heater a couple of months ago, I noticed that it was backdrafting. After a process of elimination, it was determined that the attic fan was causing the negative pressure, so I had an attic contractor turn off the humidistat to the attic fan. I was told by an attic contractor that the problem is that I do not have enough attic mushroom vents, so he reccomended that I install 10 new vents to prevent the negative pressure. So, I'm stuck between a rock and a hard place. Should I completely shut off the attic fan, avoiding it altogether? Or, should I have the contractor install these 10 mushroom vents? Are attic fans worth it?? Thank you!
New Attic Fan Causing Backdrafting
