If you post your gas and electric rates a calculation can be done to see how much it costs to run the gas furnace versus the heat pump. The efficiency rating of the furnace will also be needed. There are some places where heating with gas is always cheaper than using a heat pump.

Bosch Indoor AIr Handler Unit Model - BVA-36WN1-M20 Model Number 8733952440 208 volts

Condensing Unit Model BOVA-36HDN1-M20G Model Number 8733952437

Electric rate - 28c/kwh

Natural gas - 1.3/therm

Thanks

What is your furnace efficiency? Your electric rate is twice mine! Even at that, it is more cost effective for me to use my high eff Trane furnace exclusively. I have not used my heat pump for heating in my dual fuel system in over five years. Thanks Duke Power! That‘s the difference in regulated electric rates versus more market system pricing for nat gas.

IMO

I made the calculations for both 80% and 95% eff furnace. It is more cost eff to use nat gas exclusively. Forget DF and the heat pump. No cost advantage at all.

IMO

"Also with wifi thermostats that display outdoor temperature, do we still need to run a sensor cable from thermostat to the outside"

Honeywell wifi thermostats such as the T5+, T6 Pro, T9, and T10 Pro can obtain the outside temperature from the Internet eliminating the need for a sensor.

I would still run a sensor outside to the unit. It will be the most accurate. The temperature can vary a few degrees from a reporting station to an actual location in question, not to mention the sensor will work even if the internet goes down. Given his electric rates though I would be running NG 100% of the time.

Thank you guys - your responses are very useful to me

An outside temperature sensor is fine if you are able to install it so that it will never be hit with direct sunlight. If you can't then you are better how picking up the temperature from a nearby temperature station. In this situation it doesn't matter since the dual fuel system is not going to save money. However there may come a day when natural gas prices are higher than electricity or a solar panel is installed.

So, if you lose Internet or WiFi, does your HP lose the ability to heat due to lack of outside temperature info?

Does the high efficiency of the heat pump outweigh the higher electricity costs at some point?

You will never be able to justify a high eff heat pump with OP‘s electric rates and the cheaper nat gas. Plus one has to take into consideration the shorter average life of a heat pump versus a nat gas furnace....

IMO

The heat pump may have a high efficiency but it's fuel is expensive electricity. You would need a COP (Coefficient of Performance) value of over 5.5 just to be even with the cost of the gas furnace. This is the reason you don't see many heat pumps where electricity costs are high and natural gas is available.

Mike,

Makes it a real math drill that needs to be revisited periodically if one has no NG available but does have Oil and Electric. More competitive for total fuel cost!

Is the Heat Pump COP the same as the HSPF?

No,,,if you know the HSPF, you can get the COP with a calculation. As i recall, you can divide the HSPF by 3.5 and that will get you close to the COP.

TD