The milder temperatures of spring can make it increasingly difficult to obtain a valid radon test for your prospective home, unless everyone is clear about proper testing procedures and conditions, mainly, that you cannot open windows and doors, no matter how pretty it happens to be that day. Wait, what?!

Did you know that opening your windows during a radon test, even for a short period time, can not only impact your test results, but render the test invalid?

Radon Testing Closed-House Requirements

If you are conducting a short term test (less than 4 days), which is typical for a real estate transaction:

  • Close all of your windows on every level and all outside doors at least 12 hours before beginning the test.
  • Throughout the test, “closed house conditions” must be maintained. This means keeping all windows closed for the duration of the test.
  • Keep outside doors closed except for normal momentary entry and exit.
  • Do not operate fans or other machines that bring in air from outside.
  • Fans that are part of a radon-reduction system or small exhaust fans such as kitchen and bathroom fans operating for only short periods of time may run during the test.
  • Central heating and air conditioning systems are permitted, but wall/window air conditioning units that are set to exchange air are not.
  • Use air conditioning (central/window units on recirculate modes only) and fans to keep cool (excluding whole house fans). Be sure fans are not directed at the test device. Some test devices are very sensitive to air flow.
Tips for Surviving Closed-House Conditions

Throughout the warmth of springtime, the sizzling days of summer, and even the mild days of early Autumn, sticking to radon testing requirements for closed-house conditions can be a challenge. During these times of year, the urge for homeowners to open windows and doors is strong. But when testing for radon, doing so can completely derail your transaction time-line. Here are some tips to ensure that doesn’t happen:

  1. Set Expectations. Make sure radon testing requirements are clear to everyone up-front.
  2. Follow Pre-Test Procedures. Homeowners should close all windows/doors on all levels of the home 12 hours before the start of the test (EPA short-term test rule) to ensure a 48-hour test. They should then remain closed for the entire length of the test. Normal momentary entry and exit is OK.
  3. Know Allowable Devices. Use air conditioning (central/window units on recirculate modes only) and fans to keep cool (excluding whole house fans). Just make sure fans are not directed at the test device. Some test devices are very sensitive to air flow.
  4. Plan Ahead. When at all possible, avoid predicted heat-waves when scheduling the test. If closed-house conditions are going to be particularly inconvenient for the sellers, schedule the start of the test late in day for cooler temps. Homeowners might consider scheduling an activity outside the home for the following day if possible.
  5. Provide Access. Make sure that there is easy access to the home for the radon technician so that the test can be retrieved at the earliest allowable time.

So, use this checklist and you’ll sail through springtime radon testing!