Smart radiator thermostat batteries got empty in about 5 weeks - in what state the valve is left?

I am away from home for a week, the batteries were all normal when I left, since a few days ago I saw one of the the smart radiator thermostat's batteries went low then in a couple of days the device went offline. Now I have a couple of questions:

  • In what state was the valve left when the device shut down?
  • Is that normal that a brand new out-of-box set of batteries - I installed my tados about 5 weeks ago - went empty in so short time? What is the typical operation time of batteries?



  • I think it'll be left in whatever state it was operating in when the batteries died although some have mentioned that it appears to fail in a heat demand state so your heating may have kept on running

    Battery life is difficult to predict. I've had between 1 and 2 years from mine but I have a small, modern timber frames house. Older and/or larger properties with thicker, stone walls and greater distances between devices will see shorter battery life

  • @davidlyall Thanks for your comment, interestingly - after a couple of days the thermostat is again online with battery status normal🤔

  • It was bad battery contact probably.

    The batteries went low again in a few next day - I opened the thermostat and found a bit of paper or plastic - the one that isolates batteries during shipment - on the flipping metal part that connects two batteries together. Removed the paper/plastic - it felt a bit gluey, the battery state is normal again.