How KarbonKit works – and what we won't do

Where we came from

KarbonKit is built and maintained by Michael Fell, a researcher at University College London, with contributors. KarbonKit itself isn't a formal research project – it's a working product – but the thinking behind it draws on Michael's research at UCL into how households actually make low-carbon technology decisions. It grew out of pump:chic, a tool to let homeowners "test drive" a heat pump before deciding. The underlying calculations are documented openly on the methodology page – sources, assumptions, and the ±5%/±15%/±30% accuracy tiers.

Being built by a researcher rather than a venture-backed startup shapes how we approach this. We can take a longer view, we publish our methods, and we'd rather build something that's accurate and trustworthy than something that converts well.

How we fund this

Honestly, we don't yet. The cloud bills come out of my pocket; there's no paid plan today. The intent is for installers, manufacturers, councils and housing providers who embed at scale, or want something bespoke, to subscribe once the tools are worth charging for. We're also exploring a per-lead fee for installers who receive a homeowner's details directly through the installer finder – paid for the introduction the user chose to make, not for placement. Rankings don't change.

What we don't do

Some things we've decided not to do, even when they'd make money:

• We don't sell or share your visitors' data, unless they specifically request a quote. A postcode entered into the calculator is used to look up the property's EPC certificate, then discarded. The boiler escape plan email goes to the user only. The exception is the Get Quote flow: if a user fills in that form and picks installers to forward their details to, those installers receive what the user chose to share – that's the action being consented to, and it doesn't happen any other way.
• We don't take paid placement from installers. The installer finder ranks results by proximity and MCS certification status. No installer can pay to appear higher than another. Where you (as an embedder) have a curated panel of trusted installers, we will work with you to surface those instead.
• We don't market to your visitors. KarbonKit does not send emails to people who use a widget on your site. The widget is your conversation with your audience.
• We don't present estimates as quotes. The calculator's range bands and confidence indicators are deliberate. We want users to leave understanding that a home survey is the next step, not that they have a quote in hand.

Data we hold

For people using a widget on a host site:

• Postcode and property details – used to look up EPC data and run sizing calculations, then discarded. The one exception is a boiler escape plan a visitor asks us to email: that keeps the outward half of the postcode (SG12, not SG12 9XY) and no address at all.
• Email address (boiler escape plan only) – used once to send the plan, then not contacted again unless the user explicitly opts in.
• Usage events – page loads and widget interactions, so an embedder can see whether their widget is being used. We store the browser user-agent and a truncated IP address (the last part removed), never a full one. No cookies and no third-party advertising trackers.

For host-site account holders (people who sign up to embed widgets), we hold the account email, the widget configuration, and the embed URL. That's it.

The full detail – lawful bases, retention periods, every processor, and what to tell your data protection officer – is on the privacy and security page.

Getting in touch

If anything here looks off, or you're a community energy organisation wondering whether KarbonKit fits your work, please email hello@karbonkit.com. We'd genuinely rather hear from you early and get the tool right than have it embedded everywhere and quietly disappointing.