Lift energy audits that fit regenerative drives only where they pay back
TL;DR Liftaudit measures how much braking energy each lift in a tall building turns into waste heat, then fits regenerative modules to the lifts where the numbers work. Office towers and high-rise housing societies pay for the audit and the retrofit. It swaps out the seed's footstep tiles, which honestly produce too little power to matter.
Footsteps make very little electricity, sadly. One public display of kinetic floor tiles logged 54,267 steps producing 217,068 watt-seconds, about 4 joules a step[1]. At that rate a single unit (kWh) needs roughly nine lakh steps, by our arithmetic.
Lifts are a different story. A full car going down, or a near-empty car going up, turns the motor into a generator, and a conventional lift burns that energy off as heat[2]. When Hong Kong's government measured regenerative lifts at its Tamar offices, the energy returned came to between 17.1% and 27.0% of what each lift group used[2]. India has tonnes of tall buildings with lifts running all day, but I found no public figure on how many use regenerative drives.
What it does, in regulatory terms: an energy audit and an electrical retrofit to an existing lift drive. Changing a lift usually needs sign-off from the state lift inspector, so every retrofit is planned with the lift's maintenance company and the inspector [Requires validation for each state].
Here's how it goes. First a logger sits on each lift's supply for two weeks and records trips, loads and energy. Liftaudit then reports, lift by lift, how much a regenerative module would return and how long it would take to pay back. Add-on modules only work on lifts that already have variable-frequency drives[2], so older lifts get a different answer - replace the drive first, or leave them alone. Where the payback works, Liftaudit supplies and fits the module with the maintenance company and checks the savings for a year.
The seed wanted to harvest power from pedestrians' footsteps. The physics doesn't add up, so I'd keep the goal of capturing kinetic energy in cities and moved it to lifts, where the moving masses are a tonne or more.
The building owner or housing society pays, because lift power sits on the common-area bill. In office towers the buyer is usually the facility manager who already reports energy use. Liftaudit charges for the audit, then for supply and fitting, with a shared-savings option. I found no public Indian price for retrofit modules. One global lift maker says its regenerative drives cut energy by up to 75% compared with conventional hydraulic lifts[3], but that baseline is weak. Sell on the measured Hong Kong range instead.
In 2024 that lift maker fully modernised six lifts at a large IT company's Bengaluru office, with regenerative drives that feed energy back into the building[3], so large corporate owners do pay for this. Listed companies report their energy use under SEBI's sustainability reporting rules[4]. Hong Kong's Housing Authority has fitted regeneration to lifts with motors of 18 kW or more since 2013[2], a useful sizing rule to start from.
There is no public figure for India's lift-retrofit or lift-energy market. The narrowest numbers come from Hong Kong: returned energy of 17.1% to 27.0% across the Tamar lift groups, and 20% to 30% in a public housing estate[2]. An Indian-authored 2024 paper cites a 15% gain from regenerative drives combined with better scheduling[5]. Treat these as a range to test in Indian buildings, not a promise to customers.
Big lift makers sell regenerative drives in new and modernised lifts, including in India[3], though I did not check every maker's Indian offer. A UK kinetic-tile company now sells its kinetic tiles mostly for engagement and advertising, alongside solar hybrid tiles[6]. The gap is a maker-neutral auditor that tells an owner which existing lifts are worth retrofitting and then proves the result.
| Difficulty | Moderate (46/100) |
| Starting capital | ₹40–75 L |
| Time to launch | 6–9 months |
Logging lift energy is a breeze. Getting lift makers to accept a third-party module on lifts they maintain is hard, and inspector approvals vary by state. The Hong Kong report itself warns that payback can run long because retrofit costs may exceed the savings[2], so the audit has to be honest enough to say no to most lifts.
Audits need no licence, but fitting anything to a lift does. Plan each retrofit around approvals.
Building this outside India? The categories above usually have a local equivalent, so check with your own regulator.
Don't trust AI with anything touching lift safety or inspector approvals. Those stay with qualified engineers and the inspectorate.
Want to work out the AI layer for Liftaudit? Talk to Yash →
I like this as a narrow but honest business for an electrical engineer with lift or drives experience. If you're hoping to sell footstep tiles or green gadgets then it is not for you. First prove, across ten tall buildings, that at least a third of the lifts you audit show a payback under five years at local tariffs.
Plan for roughly ₹40–75 L, covering loggers, pilot modules and two engineers for about 15 months.
Audits need none, but changes to a lift generally need the state lift inspector's approval, and often the maker's consent under the maintenance contract.
Yes, any city with tall buildings has the same wasted braking energy. Check local lift safety rules and who may alter a lift before you sell.
The free Liftaudit validation kit has the line-by-line capital breakdown, the effort scoring, the lift-approval and electrical checklist, a 14-day validation sprint with pass/fail targets, a 90-day launch plan, 10 interview questions for building owners and facility managers, and 5 assumptions to test. Download the kit →
Thinking about building Liftaudit or something close to it? The make-or-break bit is getting lift makers and inspectors to accept a third-party retrofit, and that's the kind of thing I help founders with. If you need a hand, you know where to find me. Talk to Yash →
For illustration only. Names are fictional and ideas hypothetical; sourced facts are real but may be out of date. Nothing here is legal, financial or professional advice, and Yash Khatri is not personally liable for any use of it. Read the full disclaimer.