Thermal Comfort - cheering up the 20% | Macro

Thermal Comfort - cheering up the 20%


By Richard Horner, Account Director, Macro

Effective climate control features very highly in any office occupier’s list of basic requirements, together with sufficient personal space, tolerable noise levels and adequate lighting.  We as FMs control the HVAC systems that are operated with the intention to create ‘thermal comfort’ (defined by BS 7730 as that condition of mind which expresses satisfaction with the thermal environment).  However, both research scientists and organisations such as the HSE agree that up to 20% of building occupants will remain unhappy with their thermal comfort level no matter what is done.


So should we just focus on ‘satisficing’ (a term coined by Leaman and Bordass to describe meeting personal needs sufficiently to satisfy a reasonable proportion of users without overspending time, money or effort)? 

In a typical 50,000 sq ft office that could mean that at any given time up to 100 people are fundamentally unhappy with a core element of building services, and disgruntlement in one area can easily lead to fault-finding in another.  It is also frequently the same people that are dissatisfied, which can draw the FM team into a lazy ad hominem approach to complaints that may well be entirely valid.

The adaptive approach to thermal comfort is give people the means (or the perceived means, we’ve all been tempted with those dummy controls) to change the way people interact with the environment – such as by opening windows, choice of attire, direct control or a highly responsive FM helpdesks.  There is plenty of evidence to suggest that despite being the way all modern office buildings are now designed, the closed, energy efficient, environment comes off second best in thermal comfort terms to the warehouse conversion where someone can open a window to let in the air. 

We have tried several different approaches, which I would categorise as:

  • Ruthlessly efficient - someone asks for the temperature to be changed, it is immediately changed… often with knock on effects on people who were previously happy.  This then leads to:
  • Devolution - team leaders or department coordinators on the floors are made the point of contact for all temperature related issues.  We only change settings if they ask us.  While this reduces call volumes, it does nothing to cheer up the 20%.
  • Educational - the FM team go to great lengths to explain how systems work, lead and lag times, perceived rather than actual temperature, the physiological factors that make all our thermal comfort needs different and so on…

I would argue that the pathway to success involves combining all of the above.  To address thermal comfort, the FM team need to look at a number of related factors:  air temperature, solar gain/radiation through the windows, air speed and draughts; humidity, what activities are being performed, and how people like to dress. 

The resolution of issues is not always simple – reconciling ‘I want a view’ with ‘you need to keep the blinds down to reduce solar gain’ for example – and in any given office there are as many opinions as occupants, but time spent on gentle diplomacy can eventually be rewarded.  This is where all the relationship building and gaining of trust pays off, through moving desks, rearranging teams, communicating well and at the same time ensuring the delivery of the promised levels of heating and cooling is done seamlessly.

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