• Make sure when you hire someone for radon work, they are C-NRPP certified.  You can find a list here.
• For proof of past work (photos, past test results)
  
• For references
• For a plan and schedule for the work to be done
• If they are C-NRPP Certified (if they are, ask for proof)
• To do an onsite inspection of your home
• Whether they have liability insurance
• What steps they do as part of the ‘Communication Testing’ or diagnostics prior to installing a full system
• Whether they charge for diagnostic testing
• What type of monitor will be used to ensure the radon reduction system is working continually
• What type of testing will be conducted after the system is installed to confirm it has been effective in reducing radon levels
• To explain what the work will involve, how long it will take to complete, and how the radon reduction system will work
• For a guarantee of radon to be lowered to a acceptable level

Remember, before selecting a radon professional homeowners should always ensure they are C-NRPP Certified, get estimates, ask questions, and check references.