Ecobollix calculations!

It seems to be a load of

Nothing wrong with the figures. For a large commercial building it may make sense to change all their halogens at once - the calculations don't even take into account the cost of more frequent re-lamping with halogens.

If the replacement units produce less light and poorer quality light, then the 'savings' aren't very meaningful. The numbers themselves look ok, on a cursory look. I'd expect any premises that uses 43kW of lighting to have 3 phase.

NT

Quite true. Though in many locations (particularly those perpetually lit - such as walkways/halls/passages/stairs) the light quality may be secondary to running costs and/or maintenance costs.

Or an org that has a larger number of smaller buildings that it is responsible for.

The points it does neglect to mention though are ones like will the LEDs work as a drop in replacement on the same transformers / power supplies and will they give the same quantity and quality of light output.