More good news, the 2024 Roadrunner Comfort can now update itself autonomously (assuming you’ve connected it to your home wifi network). Each evening, between 1 and 5am, it will log onto our server and see if there’s a firmware update. It if finds one, it’ll quietly update itself and restart within a few minutes, picking up where it left off, no user intervention required.


Development efforts this summer (of ’23) focus on further improving features, performance and reliability for the next release (R2). I’m excited by the results. Hopefully this picture explains why. It shows the variation in the output air temperature, most of the time within +/- one degree. This, while the outdoor temperature increased by over 20 degrees, to a high of about 107. This level of performance can’t be expected every day. Occasional clouds and especially rain cause sharp outdoor temperature changes which, as you can see by the response to the set temperature change, can take 10 or 20 minutes to recover from. I will try to capture data showing this later this summer when the monsoons arrive (assuming they do).

If that didn’t do it for you, maybe this will: on this day, the Roadrunner Comfort held the output air temperature within +/- one degree 94% of the time, including through a two degree set temperature change (at ~11:18 above). It did take 10-15 minutes to warm back to normal operation after the set temperature change, which is about as quick as anyone can hope for with pads already quite wet on a hot day. The pads must dry out to reduce cooling (raise the temperature), which takes a few minutes.

All 15 readings more than 1.5 degrees below the set temperature occurred immediately after the set temperature was raised two degrees. If we ignore those readings, the temperature is regulated to within +/- 1.5 degrees 99% of the time. (Our other cooler, an old Tradewinds, did even better, meeting that target 100% of the time!)


  • Power consumption (controller):
    • 3W absolute maximum
    • 0.5W idle
    • 1.25-1.5W typical operating
  • Maximum Switched Current:
    • Fan: 15A High or Low
    • Pump: 3A
      • Most pumps draw around 1 amp or less
      • Some swamp coolers have a second, ‘purge pump’ which can increase pump current draw.
  • Temperature accuracy:
    • +/- 0.75 degrees Fahrenheit maximum
    • +/- 0.5 degrees typical
  • Long term temperature drift: less than .05 degrees F / year
  • Temperature sample interval: 1 minute
  • Temperature set range: 45-95 degrees F
  • Display: TFT LCD touchscreen module, 320×240 pixels
  • Bluetooth sensor range: greater than 30 feet
  • Wifi connection: Enables Time of Day, automatic updates
  • Sensor battery life: expected 5+ years; observed 2+ years
  • Sensor battery type: CR2477 coin cell
  • Absolute maximum current, fan high: 15A
  • Absolute maximum current, fan low: 10A
  • Absolute maximum current, pump: 2A (typical pump draws 1A)
  • Enclosure material: Polylactic Acid (PLA) plastic, 3D printed
  • Warranty: 2 years parts and labor