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
  • 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 remote access: home network only
  • Remote app: iPhone store, “RoadrunnerComfort”
  • Remote app cost: free
  • 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: 1 year parts and labor

Screens (release R2)

OFF Screen (starting point)

Auto takes you to automatic operation.

MaxCool runs pump and fan full time for coldest possible air

Manual takes you to manual controls

Option takes you to the Option screen

ON at time appears only if a turn-on time has been set

ON Screen (automatic operation)

Air blows at the Set Temperature (shown here as “75”)

Fan turns ON and OFF automatically

LOW (or HIGH) indicates current fan speed

WARMER raises set temperature

COOLER lowers set temperature

Fan appears when the fan is running

Pump appears when the pump is running

Sensor shows current temperature of incoming air

OFF at time appears only if a turn-off time has been set


Manually switch Pump, Fan, and fan Speed

Back returns you to the OFF screen

Shown: Pump off, Fan on low


Done returns you to previous screen (OFF or AUTO)

ON time lets you set a daily automatic turn-on time

OFF time lets you set a daily automatic turn-off time

SETUP takes you to the Setup screen

Currently shows current time

Setup Screen (no Wifi connection)

With no wifi connection, the SETUP screen looks like this

Back returns you to the OPTION screen

Rotation enables the controller to be installed horizontally or vertically

Select Wifi to connect to Wifi. Required for iPhone remote control and auto clock set.

Clock takes you to a Set Clock screen. You MUST set the clock for proper operation when there is no Wifi

The Bluetooth button starts the sensor pairing process. The button on the sensor needs to also be pressed to pair (please see sensor installation instructions)

SETUP Screen (Wifi connected)

Back returns you to OPTION screen

Rotation enables the controller to be installed horizontally or vertically

Wifi is for entering network name and password

Update enables reprogramming via Wifi

Bluetooth button turns blue when paired

Address is used to setup the iPhone app

Sensor Battery shows remaining charge

Cyan text is serial number and firmware version

Wifi Credentials Entry

Familiar keyboard, simple navigation

Done returns you to the previous screen

Set ON/Off times, Clock

Slide ‘rollers’ up and down to change setting.

Done returns you to OPTION screen

Clear disables Turn ON or Turn OFF time

Tips & Tricks

Leave the Roadrunner Comfort (RRC) ON and it will ramp up as the morning warms and wind down as the evening cools.

The fan will sometimes turn ON or OFF for just a minute or two in the morning or evening (and at night if it’s been hot).  This is normal. When the outdoor temperature is warmer than indoors, the fan will run nearly continuously.

Sometimes the RRC needs a reset to keep working properly. The RESET button is on the side of the wall unit. It’s always OK to reset RRC, it remembers ALL settings and restarts promptly.

The sensor clipped to the vent uses a battery that will last many years. When it needs changing (but with time left to get a replacement), a message will appear on the cooler display. When the battery is on the verge of failing, the message will be flashing and the controller will beep once a minute. “CR2477 ” is the battery type.