> I wouldn't be surprised if most of the savings was the new lights are LED while the old only incandescent was available

It’s definitely not the lighting, you only need a few thousand lumens to have bright elevator lighting. If you need 4000 lumens, that is (5) 60W incandescent lamps, switching to LEDs that do 100 lumens per watt (8W lamp) saves you 260 watts/hr.

The new elevator uses a VFD (they call it a VVVF) to control the motor which is where virtually all of the gains come from. Lowering the speed of the motor lowers the power usage, it’s a non-linear relationship but a motor spinning at 75% speed uses 1/4 to 1/3rd of the power that it would use at full speed.

> They likely only have whole building power consumption

You can easily measure the power of a single circuit or single panelboard using a submeter: https://www.shopemondirect.com/catalog/shop/Shop-E-Mon-Direc...