I was called to a home to perform furnace maintenance. The customer had been experiencing issues with their heating system, so I arrived to inspect it. I found that the filter was dirty and needed to be replaced. I also noticed that the ductwork was dirty and recommended that the customer have it cleaned. After replacing the filter and cleaning the ductwork, I performed a radon test and found that the level was 2.43. I explained the results to the customer and recommended that they take steps to reduce the radon levels in their home.