Non-acoustic factors in environmental noise can be broadly defined as all those factors other than noise level alone which contribute to noise annoyance and similar effects. Noise levels such as LAeq provide a good indication of the amount of physical noise present, and changes in physical noise level can be expected to correlate with changes in resident's perception, at least to some degree. On the other hand, a flexible approach to noise management based on wide consultation and communication can be extremely important. At Heathrow Airport over the last 20 to 30 years, overall aircraft noise levels have reduced because of the phasing out of the older noisier Chapter 2 aircraft types, but there are also other strategies in place which are clearly regarded as being effective both by airport management and by local community representatives and which are not as easily quantified in terms of noise level alone. This paper describes the background to noise management at Heathrow in some detail and draws a general conclusion that taking non-acoustic factors into account in addition to physical noise levels alone has been of considerable benefit over the years.