3 x 20 watt energy-saving bulbs is safer than the 40 watt tungsten ones.
The reduction in heat will be compensated by the central heating thermostat (insignificant anyway) but more to the point the heat will not stay 9 feet up and do nothing for your feet.

Turning even efl bulbs switched off & on too often can reduce their life and given the warm-up time you will get better light after a few minutes. If you really want to save electricity & money you need the light source nearer to whatever you want to look at - and use less bulbs. eg a table lamp.

Mr Red C.Eng M.I.E.E.