In this paper, a review is presented of academic literature regarding urban wind speeds for building mounted wind turbines. Site measurement of wind speed requires time and money that often are not available for small micro-generation projects. Research into wind speed estimation for the urban environment has shown that street canyons affect urban wind flow, that wind speed up over the roof ridge is only evident for isolated single buildings, that the wind resource “seen” by a building mounted wind turbine is affected by positioning (height above roof ridge and position relative to the prevailing wind direction), that urban terrain roughness is high, and that adjacent buildings can cause wind shadow. This multiplicity of factors makes it difficult to generalise a wind resource estimation methodology for the urban environment. Scaling factors may prove to be a practical solution, provided the accuracy of their use is well understood.