This study estimates airport noise annoyance cost around Düsseldorf, Germany by examining rental apartment market data. Using data on regional apartment offers we estimate rent discounts of 1.04% per additional decibel of airport noise. Other sources of traffic noise induce significantly lower price effects. As a result, airport noise annoyance costs amount to about €7.5 million a year. While the noise protection fund recovers annoyance costs, the charging regime of the airport fails to fully internalize them.