My question is about my neighbor's radon mitigation system that is on the outside of his house. I don't want to question my neighbor before I know if I've got a legitimate concern.

Our houses are about 15 ft apart and aside from the white pipe you wouldn't know it was there. However he recently added a back room and now it sounds sort of like a pool filter or one of those electric neon signs. The pipe was above the old roof line but the new roof is maybe 3-4 inches above it now. I wanted to know if, since I think its the air flow that is now altered, could the gases also be not flowing as freely in the air but settling between the houses. Our door, 2 bedroom windows and back porch are all on this side.

[Blaine Wiley]

Radon mitigation systems are installed on townhomes too, which are closer together than your house and his. I would be more concerned about whether you have radon in your home than I would be about his system venting fifteen feet from your house.

[Michael Larson]

Consider a muffler.

Mufflers currently offered for sale.

RadonSupplies has a 1 inch fiberglass lined muffler inside a 6 inch PVC S&D pipe. This muffler provided the least airflow resistance and the greatest DB reduction.

RadonAway offers a 4" PVC pipe lined with 1/2" foam. This muffler has the second greatest flow restriction but provides second best noise reduction.

The RCI baffled muffler is a 5" PVC pipe lined with 1/4" foam. This muffler had the greatest flow restriction and the same noise reduction as the straight through RCI muffler

I didn't even think about it in my own house. I'll have to pull my paperwork to see if we had that done when we bought the house 7 years ago. If it wasn't tested then, can I still do a short-term test during the summer? I read that all windows and outside doors must be closed at least 12 hours before and during testing. We have no air conditioning so our windows and doors are always open.