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bosch heat pump backup

I have installed a bosch heat pump in my two story 1850 home last October 2021 and for the most part it works ok. However when the temperature outside went down to zero the backup heat strip kicked in and never went off and kept getting warnings from my ecobee that I've been running aux mode for over three hours. in fact it never made the house warmer. My question are heat strips that effective and is there a preferred backup heat system for this arrangement. I do have oil ( from a hot water heater) and natural gas ( from a backroom fireplace). What is the best and least expensive heat backup system? Thanks.


  • Hot_water_fan
    Hot_water_fan Member Posts: 1,269
    edited January 2022
    1. Heat strips are effective in the same way furnaces are effective. They have a capacity and if the heat load exceeds that capacity, the indoor temperature decreases. So in your case, the heat strips might be too small or might be the right size. Figure out what size was installed and what other sizes are available if you can.
    2. There's no preferred backup. Many backup systems work great.
    3. What does best mean to you?
    4. The least expensive system isn't an answerable question with the information you've provided. There are backup systems that are cheap to install but expensive to run and others that are expensive to install and cheap to run. The least expensive one would support the heat pump for the cheapest total cost, but we don't know any prices nor runtime. How many total hours does the Ecobee say the strips ran? The answer might be just keeping the heat strips.
    EBEBRATT-Ed Member Posts: 13,422
    The colder the temps the less heat you get from heat pumps as you have found out, hence the electric heat coming on. heat pumps can't cut it in cold weather
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,269
    The colder the temps the less heat you get from heat pumps as you have found out, hence the electric heat coming on. heat pumps can't cut it in cold weather

    It may or may not matter.
  • ratio
    ratio Member Posts: 3,402
    If the aux heat didn't let the system catch up, you might check to see if bigger heat strips are available. Also, I'd just turn off the aux heating alert timer, this time of the year you're going to be needing aux heat. While it's more expensive to use when it's on, the overall cost of using that additional heat over the course of a heating season will be significantly less than sizing the heating system large enough to catch the few coldest days of the year.
    JUGHNE Member Posts: 10,561
    If your aux heat is short on air flow the elements may cycle on and off. Your tstat would not know this.
    Amp clamp meter on the power supply to the heaters would tell you. The control voltage is still telling aux to run but the overloads are on the 240v circuit.

    If that is the case your HP may be short on air flow also.

    Or you have 2 or more stages of aux heat and control wiring is not calling all of them on.