We have been involved in retro-fitting several Grade B listed buildings, and also a Grade A listed Charles Rennie Mackintosh building. Retro-fitting is one of the greatest and rewarding challenges, with the abundance of historical buildings and also a ticking time clock in terms of ecology and climate change. We have experience in heat pumps, bio-mass, underfloor heating and insulating old buildings to bring them into the 21st century but retaining their intrinsic character and appearance.