Buy a kit that tests for radon levels as well as a carbon monoxide monitor from a home goods store in your area.
Place your carbon monoxide detection device close to your fire alarm. This device alerts you to unsafe levels of carbon monoxide in your home.
Do not open any windows or doors in your home for half a day prior to the start of your radon test. Place the radon detection kit on the bottom level of your residence. Allow the kit to remain in place for 72 hours.
Mail your kit to the location on your label. Expect to receive the outcome of your test in about 30 days. If you receive results that state more than 4 pCi/L, call the radon office in your state to proceed.