UKAEE
United Kingdom Association of Energy Engineers. Formed in 2012 to provide networking events and other support for anybody (regardless of qualifications and prior experience) charged with saving energy at their place of work ( web site).

U-value
Measure of the thermal conductance of a building element such as a wall, roof, window or floor. For a given temperature difference inside to out, the rate of heat flow is proportional to the superficial area multiplied by U. Typical values fall in the range of 5 W/m2K for a single-glazed window to less than 0.5 W/m2K for an insulated wall. Try our on-line calculator

UPS
Uninterruptible power supply: device for maintaining electrical supply to sensitive equipment during power cuts

Utility
Generic term denoting fuel, electricity, steam, compressed air, gas or other energy carriers but also water etc.