I’ll get flamed for this, but the way in which we design and occupy buildings has changed. We look at tighter envelopes which are pressure tested (in accordance with part L) so that we get no natural ventilation. The density of occupation is huge beacuse land/buildings are so expensive, windows are minimised to reduce solar heat gains so we need more lighting, our IT systems are so much more powerful but also emit a LOT of heat. So, in summary we need air conditioning; ideally designed intelligently with correct zoning and the use of passive chilled beams or the like. I have seem loads of modern buildings have VRF and split systems retrospectively installed. Simplistic and idiotic questions are asked of clients; “can you tolerate 28degC for 2 days of the year?” but the more pertinent questions are “can you tolerate 27degC for a month, 26degC for a few months?” “Can your FM tolerate hourly complaints from the workforce?”. Giving the workforce control of occupied space temperatures is ridiculous. Just take the TRVs off the emitters.