Closed-House Conditions

  • Doors and windows must be kept closed aside from normal entry and exit

  • Window air conditioners can be run on recycle mode only

  • Central heating and cooling appliances can be operated normally

  • Window and whole house fans must be turned off

  • Existing radon mitigation systems should be left on

  • Crawl space vents should be in normal seasonal position

Why is this important?

It is important to know how high the radon levels CAN get. It is true that on a warm summer day it is likely that windows will be open to ventilate and allow fresh air in (and radon out). But it is also true that on a cold and wet winter day, windows will be closed and ventilation will be minimized. It is this condition that we are trying to reproduce. We want to know how high the radon levels can get under normal living conditions.