Why do we test for Radon in the winter? What are the advantages?

You test for radon in the winter because indoor radon levels are usually highest when homes are sealed up.

Here’s why:

1. Homes are closed up – In winter, windows and doors are mostly closed, so less fresh air enters. Radon, which seeps in from the soil, can accumulate more, giving a more accurate reading of the worst-case scenario.

2. Stack effect – Warm air inside rises and escapes through the upper parts of the home, creating a slight vacuum that pulls more radon from the ground into the lower levels.

3. Consistent conditions – Winter tends to have fewer drafts and more stable indoor air patterns, which makes short-term test kits more reliable.

Tip: Even if you test in another season, you can still detect radon, but winter gives a reading closest to the maximum potential exposure in your home.