Classroom HVAC Automation.

Scheduling Challenges:

Being a multisite church we have always had the struggle of scheduling groups and making sure the room is at a good temperature while not excessively heating and cooling unoccupied spaces. We have been using Planning Center Resources for the last few years as a facilities scheduler and while it's not perfect it is a huge improvement over the large paper calendar our facilities team had maintained.

One thing PCO Resources has always lacked was integration into a building management system. Most of our spaces are controlled via a large Carrier iVue system which unfortunately has few possibilities to integrate with outside systems without a major undertaking. But a few of our smaller new disconnected spaces are completely separate from our iVu system which posed a bit of an opportunity for integratgration.

Welcome the Ecobee 3:

Ecobee3 thermostat on wall

This small smart thermostat has many features but the few that we were most interested in were:

  • Remote wireless temperature sensors.
  • API with IFTTT integration.
  • Remote management.
  • PIN lock to prevent changes.

We have mounted the Ecobee's at the HVAC units to keep them away from prying eyes and fingers. In each space served by the HVAC unit we have placed a small ecobee wireless sensor.
Ecobee wireless sensor on wall The sensor detects motion and temperature in the space. Unfortunately the motion sensing was a bit of a let down, It rarely worked reliably. (Fix coming in a later post)

Override buttons:

A common thing in commercial HVAC systems is an override button, they commonly add 3 hours of occupancy to the HVAC system in a room at the push of a button. This became critical since the motion sensing of the ecobee wireless sensors seemed to be a dud. The override button also provides a sense of control to the end user. We looked at a few different IFTTT compatible wireless buttons and landed on the Amazon IOT Dash button.
AWS IOT BUTTON A perfect small wifi enabled button that can trigger a IFTTT event when pushed that costs $19 each.

IFTTT If this then that:

If this then that is the glue that ties the Ecobee, Planning Center Resources and the Push button together.

Resources allows you to export a webcal calendar for a specific room to a Google Calendar account which IFTTT can trigger off of an events start and stop times.

Google Calendar with events

We created four rules for each thermostat:

  • Set thermostat to home 30 minutes before event.
  • Set thermostat to home at event start.
  • Set thermostat to away at event end.
  • Set thermostat to home for 3 hours on button push.


End result:

With all of these technologies working together we now have a fairly seamless experience for groups that use these new spaces. The HVAC system automatically kicks on before their event getting the room to a comfortable temperature and turns off as soon as their event ends saving a significant amount of money. With the Amazon IOT button we also account for those unexpected uses and if an event runs past it's scheduled time. I have ordered in a few DLink wifi motion sensors which integrate perfectly with IFTTT and by extension the Ecobee. I'll update this post if they prove successful.