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JackMS's avatar
JackMS
Explorer
Jan 07, 2014

Heat pump working at 28 degrees ambient

I did an experiment with my heat pump tonight. Wanted to see at what temp it would switch to the furnace. It is down to 28 right now and the heat pump is still running blowing 104 degrees out the vent about 3 feet away. I would have thought it would have iced up by now but doesn't show any signs of it. Temp inside the mh is about 42.

Should I be impressed it's doing so well or worried it hasn't switched to the furnace? I am going to switch it manually before I go to bed if it doesn't do it on its own.
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  • Semi_Retired_Gr's avatar
    Semi_Retired_Gr
    Explorer
    Jan 07, 2014
    Seems to me the question is at what temperature does it become more efficient to heat by gas? I have my home heat pump switch to GFA at approximately 36-37 degrees. Keeps us comfortable and the combined electric/gas bills reasonable. All obviously depends upon the price of electricity versus gas, efficiencies of each unit, installation parameters, etc. etc.
  • RayChez's avatar
    RayChez
    Explorer
    Jan 07, 2014
    The two heatpump/airconditioners on my coach will work real good until it gets down to 30F degrees, then it will switch over to the furnace. I hardly ever use the furnace IF I am hooked up to shore power.
  • MrWizard's avatar
    MrWizard
    Moderator
    Jan 07, 2014
    so why the "ODD" title of '28 ambient' ?

    approx 40F is the common quoted figure depending on the humidity and wind chill
  • wallynm's avatar
    wallynm
    Explorer
    Jan 07, 2014
    Would guess your roof temperature is a little higher than your outside thermometer.
  • Taco's avatar
    Taco
    Explorer
    Jan 07, 2014
    My coleman mach 3 heat pump seems to work well into the low 30s but then switches off. I guess I am satisfied enough with the performance, I don't really camp much when it is super cold anyways.

    The heatpump in my house however can keep it warm much much lower. It works into at least the low teens, but it will get put to the test tonight. Single digits forecast for RVA.
  • SuperDutyFiver's avatar
    SuperDutyFiver
    Explorer
    Jan 07, 2014
    I know my Carrier will make heat down into the upper twenties-although the exact temp does vary I think it depends on the wind/humidity maybe-anyhow eventually it gives up and flips over to the furnace(usually it will cycle once or twice-and sound it-and then the furnace kicks on) I've tried to make it a point to shut it down when the temp is below 32 or 33 because I don't want to strain it.

    I'm impressed that the unit is producing heat that warm.

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