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Is there a thermostat or control that will use one heating system vs a second based on time of day

Steve Garson_2
Steve Garson_2 Member Posts: 712
edited June 2023 in THE MAIN WALL
I have natural gas baseboard heat as well as split system heat pump. Has anyone created a control that will use the boiler during a set period, say 11AM to 7PM when electric rates are high, and the heat pump from 7PM to 11AM when electricity is less expensive?
Steve from Denver, CO


  • pecmsg
    pecmsg Member Posts: 4,952
    Where is gas cheaper than a heat pump!
    JUGHNE Member Posts: 11,104
    Would the water heater type time clock switch between the boiler and the air handler?

    Any time clock with a single pole double throw switch function might work, it would be in the basement.

    Use just the same tstat that calls for heat now.
  • hot_rod
    hot_rod Member Posts: 22,472
    just a double throw 24V RIB on any programable stat. The program toggles the relay to chose either or heat source.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,166
    edited June 2023
    I think the timer with a 3 pole relay would work. I have dummied up a drawing with a typical heat pump and a typical boiler. When the timer is on the Electric system, All the wires are connected to the HP low voltage system. When the timer is on the gas system, the Compressor, Fan, and Electric heat are disabled by the relay and the other contact in the timer engages the gas heat on the same thermostat.

    You could also use two thermostats. It would be simpler and you could get a different temperature based on the timer setting. (if that happens to line up with the electric rate change timing)

    hot_rod said:

    just a double throw 24V RIB on any programable stat. The program toggles the relay to chose either or heat source.

    I'm not exactly sure how the heat pump might operate with a RIB Relay only on a setback thermostat Bob. when the setback happens, you operate all the system controls at a different temperature. The RIB will only be energized or de-energized based on the call from the thermostat. It will not actually operate the other appliance at the set point temperature.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?