Central heating switch design?

[jackhutchinson]

i have been asked to design a method of turning on the central heating in my company office only when people are inside. this is due to the central heating currently being on a timer switch. which is fine from monday to friday however when the workload is high people can work weekends. this happens frequently but not often plus the weekend work isn't on a time table so they can come and go when they please. having the central heating come on every weekend due to the timer is costing my company money and i was wondering if their was a way in which the central heating could operate only when there is someone in the office. i have considered wiring switches to the lights or alarm and considered a simple switch however i just wondered if there where any more ideas.

[Jimbo]

The simplest way is a 7 day timer then set it up for what you want relying on people to turn lights off etc is a very touch and go business. You could activate it through PIR, etc etc but much more complicated and costly. Regards Jimbo