I am trying to determine what is the most efficient thermostat setting for a heat pump / heat strip system. I currently have a thermostat that will only allow me to determine when the heat strips turn on to support the heat pump by time. So currently, I have the heat strips set to turn on 20 minutes after the heat pump turns on in the hope that under normal circumstances the heat pump will do its job in that amount of time and turn off without needing the heat strips but under colder than normal conditions, the heat strips will turn on.
This seems very limiting. I know many thermostats will use the temperature to determine when to turn on the heat strips. For example, if the set point is 72 and the room temp drops to 3 or 4 degrees below 72 then the strips will turn on to supplement the heat pump. The only downside of this is that if the heat pump is only able to maintain the current temp and not increase the temp than the heat pump will run continuously and not trigger the heat strips, or at least will take several cycles and more time to get to the point of the strips turning on.
Does anyone have any input on what is the best trigger for turning on the heat strips? Also, I am not sure what the ideal setting is for the time delay option. I chose 20 minutes but if I make it shorter it may run the strips too often and if I make it longer, then when it is very cold out, the heat pump will always be guaranteed to run for that amount of time before turning on the heat strips.
Thanks for the help.