Earth Notes: Smart Radiator Valves Video

1014s "20201112 EcoHomeLab talk on smart thermostatic radiator valves TRVs [VIDEO]" (poster) Uploaded . Download MP4 video clip 22735kB (may not be available in data-saver/lite mode), download low-bandwidth MP4 video clip 21007kB, hi-fi/original MP4 video clip 28508kB.

Slide Text Content


  • What problem is being solved?
  • What is the solution? Does it work? What about the rest?
  • Some history
  • Where we are now: SAP, GHG, ECO3
  • How does it work?
  • Secrets for developers

Problem: climate change, space heating

  • Carbon emissions contribute to climate change
  • In UK ~10%+ of all carbon emissions from domestic space heating
  • Maybe 50% of that is unnecessary
  • One huge source of waste: heating empty rooms, eg bedrooms during day
  • Another: complex / expensive controls that fox users
  • Not everyone has reliable always-on Internet

Solution: soft zoning, Radbot

  • Treat each room/rad/TRV as a soft heating 'zone'
  • Set back temperature when vacant and likely to be so for next hour or so
  • Set back further when more sure, preheat when occupancy predicted
  • DON'T require programming or connectivity or attention
  • (Reasonable evidence that autonomous measures persist better)
  • Occupancy detection is driven by light (in various ways), use of controls and other things (development continues).
  • Size of temperature setback is risk-weighted.

Brief history

  • ~2009 David MacKay discussions re SEWTHA
  • At DECC, what was best carbon bang for buck?
  • Late 2012 meeting, home heating including zoning good
  • 2013 OpenTRV project
  • 2018 Vestemi commercialisation to try to reach >>1bn radiators!
  • Tests (Energy House) and trials (ROWR and ECO): yes, it works


  • Sales, sales, sales (every Radbot can save ~0.1tCO2/y)
  • Cost reduction, continuous improvement (h/w and data science)

SAP, GHG, ECO3: alphabet soup!

  • Where would we be without TLAs and ETLAs? B^>
  • Industry awards and key accreditation… SAP
  • Standard Assessment Procedure for home Energy Performance Certificate
  • SAP score allows use under Green Homes Grant
  • Coming: Energy Company Obligation deemed scores for ECO3 programme

How does it work?

  • Just like a mechanical TRV, simple display, dial clicks
  • Plus boost button!
  • Occupancy/vacancy detection
  • Prediction and 'usual at this time' 7-day-ish memory
  • Sensors: light, temperature, humidity, use of controls
  • Outputs: motor valve control (+haptics!), LED, radio
  • Some patent-pending cleverness too...
  • 60% savings in bedrooms, up to 30% realistic in suitable homes

Some secrets for developers and tinkerers!

  • Radbot 2 exposes serial connection (4800 baud, 8n1) for CLI
  • Key and ID can be set via the CLI (Command Line Interface)
  • JSON stats receivable by OpenTRV stats hub and boiler controller


  • 8 years in the making: in stock!
  • Ready for Green Homes Grant and ECO3
  • Aim is to save megatonnes of CO2, affordably and simply
  • Also aim to help reduce fuel poverty
  • Supports tinkering

Get in touch, buy Radbots, cut carbon!

  • Damon Hart-Davis

Show Notes

My presentation (~17 minutes) brutally extracted from the live EcoHome Lab Zoom meeting video of the larger smart radiator valves meeting (thanks Matt of Carbon Co-op!) without top or tail.

It was a good evening with some familiar faces, about 16 people present, from around the UK.

(The covid-19 pandemic lockdown was a thing...)

Download PDF slides for the talk.

Locally-recorded audio:

1039s "EcoHomeLab talk local audio" Uploaded . Download mono MP3 audio clip 5897kB.