I will be replacing my current A/C unit with a Trane XR13 heat pump. The installation includes a Honeywell VisionPro thermostat. This will be my first experience with heat pumps. I live in Central Indiana.
I have been given conflicting advice from two HVAC sales professionals regarding using an outside temperature sensor to switch between the heat pump and my gas furnace.
1) Salesperson 1 said I need a sensor to switch back and forth between the heat pump and my gas furnace based on the outside temperature. This is the traditional method used in heat pump applications.
2) Salesperson 2 said I should go without a sensor. The explanation was that this way EVERY time the thermostat calls for heat, it will first go to the heat pump to try and heat the house. If it is unable to heat the house and the temperature continues to drop, the Adaptive Intelligence feature of the thermostat will switch over to the gas furnace to heat the house up to the required temperature setting. This way I would get more use out of the heat pump on days where the temperature might be below the traditional 30-38 degree F switchover point. As an example, he pointed out that on a 20-25 degree F, clear sunny day where the house was getting some “solar heating”, it might be sufficient to use the heat pump to warm the house back up to the set temperature. In other words, he said that the outside temperature was only one factor determining the heat required to warm the house; others included clouds, sun, wind/air infiltration into the house, etc. He also said the heat pump is designed to work down to minus 30 degrees F.
The second scenario appears to make sense if indeed the thermostat is smart enough to know when to switch back over to the gas furnace based on the inside temperature continuing to drop after the heat pump has been activated.
Any thoughts or suggestion would be appreciated on whether Scenario 2 makes sense and is a viable scenario with the Honeywell VisionPro thermostat.