How IMPT's carbon offset actually works (the on-chain bit, explained)

Hook

Most "carbon-neutral hotel" claims are nonsense. The hotel doesn't measure its actual emissions. The offset isn't verified. And nobody can show you proof that the credit was actually used. That's the problem we set out to solve at IMPT. Here's exactly what happens behind the scenes when you book through us.

The Problem

The voluntary carbon market has three failure modes. One: the underlying carbon project might not actually exist or might be over-credited — the original tonnes never got removed. Two: the credit gets sold but never officially "retired" in the registry, so the same tonne ends up sold to multiple buyers. Three: the consumer has no way to verify any of this. The whole chain runs on trust, and most of it doesn't deserve the trust.

What Impt Actually Does

When you book a hotel through impthotels.com or app.impt.io, four things happen:

First, the booking is processed at the same price you'd pay booking direct. We do not add a green premium. The cost of the carbon offset comes out of our supplier commission — not your wallet.

Second, we purchase a UN-verified carbon credit. UN-verified means the credit comes from a project that's been audited under the UN's CDM standard or an equivalent registry like Verra or Gold Standard.

Third, that credit gets retired on-chain on Ethereum. "Retired" is a specific legal action — it permanently marks the credit as used in the registry. Once retired, it cannot be sold to anyone else, ever. The on-chain part means the retirement event is logged on Ethereum, with a public transaction hash anyone can inspect on Etherscan.

Fourth, the retirement gets associated with your booking, so if anyone ever asks "did this booking really fund a real offset", the answer is provable.

The Maths

A typical hotel night creates around 36 kilograms of CO₂ — that's the IEA Buildings figure, which is what the Cornell Hotel Sustainability Benchmarking Index more or less converges to as well. Lights, hot water, heating, breakfast, laundry, the share of the building's HVAC that's allocated to your room.

We retire one full tonne — 1,000 kilograms — per booking. That's about 28 times a single night's footprint. Or roughly four weeks of hotel nights covered by a single booking's offset. Even a long stay, you're more than handled.

We can do this because we're operating at scale across a 1,985-property Irish inventory and 8 million properties globally. Per-credit cost falls when you're buying in volume, and it's still small relative to the supplier commission on a hotel booking.

Why On-Chain

This is the part most people get wrong. On-chain isn't a marketing buzzword. It's the verification layer.

When you retire a credit "off-chain" — through a registry alone — you're trusting the registry. They're typically reputable, but their internal databases aren't public, and you have to take their word that your specific credit got marked retired and not transferred somewhere.

When you retire on-chain, the action is written to a public ledger. Anyone with the transaction hash can pull it up on Etherscan and see: this credit ID, this date, this retirement, this purpose ("IMPT booking #XYZ"). It cannot be reversed. It cannot be modified. It is verifiable to anyone for as long as the Ethereum chain exists.

This matters because the entire problem with the voluntary carbon market is double-counting and fraud. On-chain retirement makes both impossible.

WHAT WE'RE NOT CLAIMING

I want to be careful about what we are and are not saying.

We are NOT saying the hotel itself is "eco-certified". The Hilton Dublin you book through us is the same Hilton Dublin you'd book through Booking.com or direct. We're not auditing their operations. We're not making claims about their food sourcing, their energy mix, their staff training.

What we ARE saying is: the booking transaction carries an offset. We have moved the carbon question from the property layer — where it depends on hundreds of properties each doing their own work to varying standards — to the booking layer, where one verified mechanic covers every booking on the platform.

That's a different problem space. It's not better or worse than property-level work — they're complementary. But it's the one we can credibly handle at scale, today, without depending on any specific hotel's claims.

How To Verify This Yourself

If you book through IMPT and want to verify the offset actually happened, here's exactly what to do.

We publish the on-chain retirement records on impt.io. Each booking has a corresponding Ethereum transaction hash. You take that hash, paste it into Etherscan.io, and you'll see the retirement event — the credit ID, the project it came from, the date, the retirement label.

If you ever can't find your booking's retirement, that's a bug, and we want to know. Email mike at impt dot io with your booking reference and we'll send you the tx hash.

This is not a feature we hide behind a chat widget. The whole point of putting it on a public ledger is that anyone can verify.

Wrap

Carbon offsetting has a deserved reputation problem. Most claims are vague, most credits are recycled, most consumers have no way to verify. We built IMPT specifically to solve that — by paying for the offset out of our commission, by buying only UN-verified credits, and by retiring them on-chain so the verification layer is public.

If you're booking a trip to Ireland, you can use any platform you want — but the carbon question is harder to wave away if your platform shows you the receipts.

That's it. That's the whole mechanic.