With regards to the letter by KD Overment in your issue of 31 July (page 22), I have been involved in many projects for university buildings and find the attitude of the estates departments often depressing

I recently produced a feasibility study for a river-based heat pump for a college. We demonstrated that the heat pump had a payback of seven years – unusually short. Guess what? They opted for a new gas boiler! As an engineer specialising in sustainable design technologies, you can imagine I found this depressing. Who can we convince? Certainly not most developers.

P W Tracey, TDP