How to waste energy No. 6: air conditioning

The hot weather brings with it demands for air conditioning, and with that comes a whole raft of excellent ways for organizations to waste energy. Here are my top ten hot tips:

1. Don’t argue when people ask for rooms to be cooled to 20C rather than the more sensible 27C. Every degree reduction in set-point adds 10-15% to the electricity used for cooling, and you may even hit the jackpot of some people turning on electric heaters as well.

2. Encourage people to leave the windows open with the air-conditioning on. This allows warm air in and expensively-cooled air out, more or less guaranteeing that the air conditioning will have to run flat out without reaching the desired internal temperature.

3. If it is not possible to leave the windows or doors open, minimise the recirculation of ventilation air.

4. Do not take advantage of lower overnight outdoor temperatures to pre-cool occupied spaces.

5. Encourage people to leave idle electrical items running, to increase the heat gains. Desk fans are an excellent example for those who can appreciate the irony: by creating air movement they make the occupants feel more comfortable, while continuously heating the air a little.

6. Believe your IT department and equipment suppliers when they say their kit needs to be housed at 16C (the idea that it might be designed to operate in tropical climates is ridiculous).

7. In computer rooms have the equipment racks all in the same space, so that their warm extract air mixes with the chilled air needed for intakes. Under no circumstances partition the space to separate cold and warm air.

8. If possible, house people and equipment racks in the same space as if they needed and/or could tolerate the same conditions.

9. Do not shield windows from direct sunlight.

10. Always use artificial cooling when increasing the ambient fresh air supply would do the job equally well.

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