There are a number of reliable detection methods available for assessing the average radon levels within your home. Any of these can determine whether or not there may be a risk worthy of further study or remedial work (i.e. work to reduce radon gas levels). From the scientific point of view, the longer the testing procedure the more accurate the results may be. The preferred method is to test over a period of typically 3 months, however methods of detection have been developed that give accurate readings of radon in a period as short as 7- 10 days usually essential in house conveyancing operations. They are a popular technique in both the USA and the UK. Caution:- The Radon Council is aware that some organisations are operating in the UK offering “Instant” radon sampling measurements using portable measuring equipment. Because radon levels can and do vary considerably throughout the day, any measurements of less than 4 days should be avoided. As with any measurement technique it is the interpretation of results that are important. Such interpretation recognises difficulties in sampling, house construction, ventilation and human activities, as well as seasonal changes. Given proper interpretation the short-term tests are equally acceptable in deciding whether there may be a need for further detection or remedial work. A number of reliable and fully experienced companies offer a range of long term detection methods and several offer the 7-10 day tests as well.