Yes, a VFD cuts elevator energy use by matching motor speed to actual demand instead of running full speed all the time. The size of the saving depends on traffic pattern, drive type and whether regeneration is fitted, so it is a range with conditions, not a fixed percentage.
What a VFD Does to Save Energy
How a VFD saves energy: speed matching instead of full-speed running, plus smoother starts and stops.
Why a Fixed-Speed Lift Wastes Energy
A lift without a drive runs its motor at fixed speed and wastes energy in braking and throttling; a drive trims output to the trip at hand, and the modernization article lists heat, noise and smell as signs an old fixed-speed setup is past its best.
When the Saving Appears
The saving appears after a retrofit or a new installation with a drive; it is largest in buildings with varied traffic, and smallest where the lift already runs near full load all day.
Where the Saving Applies
Machine rooms and lift systems of all building types; the closed-loop articles show precision and hold benefits alongside energy, not instead of them.
How to Judge Whether a VFD Cuts Energy Use
- Record the building’s traffic pattern first: peak hours, idle hours and typical trip lengths.
- Confirm the drive type: open-loop or closed-loop, since closed-loop adds precision levelling and zero-speed hold on top of energy saving.
- Check whether regeneration is fitted: it returns braking energy instead of burning it as heat, where the installation supports it.
- Compare before and after on the same traffic pattern, not on different weeks.
- Keep ventilation and tuning in order: a poorly tuned drive hunts, draws extra current and gives back part of the saving as heat, as the overheating article sets out.
- Judge the result over a season, not a single day, because traffic varies.
Where the Saving Comes From
| Source | How it saves |
|---|---|
| Speed matched to demand | Motor does not run full speed for light trips |
| Smooth starts and stops | Less braking waste, less mechanical stress |
| Regeneration, where fitted | Braking energy returned instead of burned as heat |
What Limits the Saving
| Limit | Effect |
|---|---|
| Near-full load all day | Little idle time to save from |
| Poor tuning or hunting | Extra current returns as heat |
| No regeneration fitted | Braking energy is lost, not recovered |
For replacement planning, see the replacement article and the 11LIFT closed-loop elevator inverter product page.
Frequently Asked Questions
Does a VFD always save energy?
In varied-traffic buildings yes; where the lift runs near full load all day, the saving is small.
Is regeneration required for savings?
No: speed matching alone saves; regeneration adds more where the installation supports it.
Does closed-loop save more than open-loop?
The main energy saving comes from speed matching in both; closed-loop adds precision and hold, not a separate energy claim.
If the electricity bill does not fall after a retrofit, is the drive faulty?
Not necessarily: traffic growth, poor tuning or a change in usage pattern can mask the saving, so compare on the same traffic pattern first.
What maintenance protects the saving?
Ventilation, tuning and trip-history checks: a hunting drive gives part of the saving back as heat.
To assess your building, send IDEEI your building traffic pattern and current drive type for an energy-saving assessment.