Radon
A radon test in the pack is from another year and the fan was off. What of the present level was not measured?
The present radon level was not measured. A test from another year, taken with the fan off, is an old result under different conditions. It does not record the level in the house now, with the fan as it stands, the vents as they are, and the rooms as they are used. This survey did not place detectors and did not run a radon test. A map and a previous report are separate from a current measurement. The older paper is not this year's reading. The report can note that paper and the fan. It has not measured the present level.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
Radon results depend on the season, how long detectors stayed down, whether a fan was running, and how the house was ventilated. A test with the fan off answers a different question from a test with the fan on. An old test answers neither question for today. The surveyor is not a radon laboratory. Seeing a fan switched off records the switch. It does not repeat the old test and it does not create a new one. The present level remains unmeasured whatever figure the old paper contains.
Show the old report to your solicitor as a document in the pack, and do not describe it as the current level. If you want a present figure, that is a new test with detectors left in place for the proper period, which this visit did not start. A lender may ask about radon papers in some areas. The accurate statement is that an older test exists, the fan was off, and today's level was not measured. The survey has not said the house passes or fails a radon screen.
What should you ask your surveyor?
- Does the old report itself say the fan was off, or is that only what you saw today?
- Is the fan a radon fan, and was any other mitigation, such as a membrane, visible?
- Does the pack claim a later test that was not actually enclosed?
What are the typical next steps?
- Treat the older test as historic and the fan position as today's observation.
- Do not quote that paper as the present radon level.
- If you need a current figure, commission a new test this survey did not start.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Does a map colour replace the missing present measurement?
No. Maps show area likelihood, not the level in these rooms today. They are a different product from a detector test and from this home survey. A map can be a reason to ask for a test. It cannot stand in for the measurement that the old fan-off report also fails to give you now.
Should the fan be switched on and the old result discarded?
Do not switch equipment as a substitute for a test, and do not ignore a document that is in the pack. The old result remains a past test with the fan off. Whether the fan should run is a question for the mitigation papers and a radon specialist. The survey did not measure either condition.