Radon Connect
Printable checklist

Before you test

More radon tests are invalidated by conditions than by faulty devices. Everything on this list happens before the device starts counting.

Print this and put it on the fridge. In an occupied house, the people who can invalidate your test are the ones who have not read the instructions.

13 items in 3 sections · 6 marked hard to reverse later

Twelve hours before the test starts

  1. Close all exterior windows and doors, and keep them closed except for normal entry and exit — hard to reverse later

    Closed-building conditions are the protocol. Ventilation pushes the reading down and makes the result challengeable.

  2. Switch off whole-house fans, attic fans, window air conditioners, and evaporative coolers — hard to reverse later

    These move outdoor air through the house in volume and will dilute the measurement.

  3. Leave the furnace, heat pump, or central air on its normal schedule

    Permanent HVAC operating normally is part of the protocol — you are measuring the house as you live in it.

  4. Tell everyone with access what the conditions require, in writing — hard to reverse later

    In an occupied home being shown or lived in, several people can invalidate a test without realising it.

Choosing where the device goes

  1. Choose the lowest level you live in or reasonably could — hard to reverse later

    This is the conservative, comparable benchmark used across houses — not necessarily where you spend the most time.

  2. Place it at least 20 inches above the floor

    Floor-level placement does not represent the air people breathe.

  3. Keep it several feet in from exterior walls

    Perimeter air is influenced by the wall rather than the room.

  4. Keep it away from windows, vents, fireplaces, and anything blowing air

    Drafts distort the reading toward the draft rather than the house.

  5. Do not place it in a kitchen, bathroom, laundry room, or crawl space — hard to reverse later

    Humidity and airflow in those rooms produce a number describing the room, not the house.

Record before you start

  1. Write down the device type and its identifier

    A result you cannot attribute to a device is hard to defend if challenged.

  2. Write down the exact location, including floor and distance from walls — hard to reverse later

    A retest must use the same location to be comparable.

  3. Write down the start date and time

    Duration matters, and short tests get invalidated by early collection.

  4. Note the weather, especially a storm front or high wind

    Guidance advises against testing during severe storms; noting it helps interpret an unusual result.

What this checklist does not cover

A checklist that pretends to be complete is worse than one that states its edges. These are the things deliberately left out, each with somewhere better to go:

  • This checklist covers preparation, not interpretation. Use the result interpreter once you have a number.
  • It does not cover radon in well water, which is a separate test with separate treatment.
  • It is not specific to any state requirement. Where a state specifies devices or procedures for a given purpose, that specification governs.

Related

  • During testing — Four days of not doing things. That is genuinely the whole job.
  • Buying — Order early, verify the existing system, get it in the amendment.
  • Selling — Test before you list. Everything else follows from that.
  • Should I test? — Five reasons to test, and which one applies to you.
  • What does my result mean? — Your number, read against guidance and against the conditions it was measured in.
  • Build a testing timeline — Work backwards from your deadline to the day conditions have to start.
  • How testing works — Devices, placement, closed-building conditions, and what invalidates a result.
  • False positives — Most disputed results are not false — they are invalid, mismeasured, or comparing two different things.
  • Weather effects — Weather genuinely moves indoor radon — but it explains variation around a number, not a number well above the action level.
  • Monitors vs short-term tests — Which instrument to use, and why transactions favour monitors.
  • All checklists — every printable list on the platform.

Confidence and limits of this page

Every decision resource on this platform states its own boundaries. This is not a disclaimer — it is the part of this checklist you should read before relying on it.

What we knowClaims on this page we stand behind, each traceable to an approved source or to observable structure.
  • Closed-building conditions must hold for twelve hours before a short-term test and throughout it. This is measurement protocol, published by EPA rather than invented here.
  • Device placement rules — lowest lived-in level, 20 inches up, away from exterior walls and airflow — come from the same protocol.
  • Kitchens, bathrooms, laundry rooms, and crawl spaces are excluded from valid placement because humidity and airflow there distort the reading.
What we do not knowQuestions you may reasonably have that this page does not answer.
  • Whether the people with access to your house will actually maintain the conditions. That is the single largest source of invalid results and it is outside anyone’s control but yours.
  • How much a specific breach of conditions moves a specific reading. The direction is known; the magnitude is not.
What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
  • Controlled experiments measuring the effect size of specific protocol breaches — one window open for one hour, a whole-house fan run overnight — would let this checklist tell you how much a mistake actually costs. We have not found that published at useful resolution.
  • A study of invalidation rates in real-estate testing would establish how common each failure mode is, which would let the critical items be ranked by frequency rather than by judgement.
What we do not claimClaims you might expect to find here and will not, with the reason.
  • We do not claim following this guarantees a valid test. A device can fail and a laboratory can err.
  • We do not claim a particular device brand or laboratory is better than another. We do not evaluate equipment.
  • We do not claim what your result will be, or that any result is safe.
What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
  • Whether your specific device is in good standing, or whether the laboratory analysing it is currently accredited. Your state programme is the authority on both.

Sources

  1. U.S. EPA — Radon
  2. U.S. EPA — A Citizen’s Guide to Radon

Get quotes from credentialed local contractors

Free to request and no obligation. We verify credentials with the issuing authority before any request routes to a contractor.

Start a request