Can I use one nest thermostat (3rd generation) for two heating sources (oil furnace and heat pump)?

[BlakeM]

Can I use one nest thermostat (3rd generation) for two heating sources (oil furnace and heat pump)? I am using W1 for oil furnace. Can I add one heat pump in the same thermostat?

[EdwardT]

Hi BlakeM,

Thanks for reaching out. Based on your description, it appears that you have a dual fuel system. The Nest Thermostat 3rd gen is compatible with this type of system. You can also click on this link to learn more about this.

Thanks,

Edward

[EdwardT]

Hi BlakeM,

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[BlakeM]

Hi Edward,

I want to confirm the following two things.

1. My one Nest is connecting with one oil furnace (W1 and Rh wire) and one AC (Y1,G and Rc) as picture below. Now I want to remove AC and replace by one heat pump. Can you tell me how to wire with heat pump?

2. How does one Nest control two heating sources (oil furnace and heat pump) at the same time? Or I just can control one at a time?

Please advise. Thanks!

[EdwardT]

Hi BlakeM,

Thanks for the response. For some reason, the photo is not loading but a heat pump wiring would be Y, OB, G, RC. Your Nest Thermostat will prioritize using your heat pump for the heating and would only use your AUX heat if it's taking too long for your heat pump to reach your target temperature.

Thanks,

Edward

[BlakeM]

Now I have uploaded two pictures for you as below.

My Nest is wiring with AC and oil furnace as you can see. But now I want to replace AC to heat pump. My installer told me that heat pump is good for temperature above 35F.

In this situation, how can I turn off heat pump and use only oil furnace as only heating source when the temperature is below 35F?

As you can see from picture, Nest has three option that I can choose. I only use "Heat" to turn on and off oil furnace and use "Cool" to turn on and off AC.

When I replace AC by heat pump, which function that I should choose? Is that "Heat.Cool" to control heat pump hot and cold air by setting the temperature?

Please advise. Thanks!

My Nest displayMy Nest wiring with heater &AC

[EdwardT]

Hi BlakeM,

Thanks for the response. When you install your heat pump, you would have to configure your Nest Thermostat with the new equipment and wiring. You would still have separate option for cooling and heating. You can click on this link to learn more about this. 

Thanks,

Edward

[BlakeM]

Thanks for your answer and link. It is very helpful.

Since my heat pump dealer told me that "We would have to install separate thermostats with the heat pump system, your existing Nest thermostats couldn’t operate two heat sources.".

I will ask them to check your information and confirm. If any questions, I will let you know.

Thanks!

[Jake]

Hey there,

I am glad to hear the link was of help. I wanted to check in with you, and see if you had any other questions from here. Please let us know, as I would be happy to review.

Best regards,

Jake

[Jake]

Hey there,

I wanted to check in and see if you had any questions. Please let me know, as I would be happy to assist, and answer any you may have.

Best regards,
Jake

[Jake]

Hey there,

I wanted to check in, and let you know that I will be locking the thread in 24 hours.

Best regards,

Jake

[BlakeM]

Hi Jake,

I do not any questions now. When my contractor install heat pump, I will check with you if they have any issues. Thanks!

Blake

[Jake]

Hey there,

I wanted to check in with you, and see if you had any questions. Did everything work out with the installation? Please let me know, as I want to ensure you are good to go.

Best regards,

Jake

[BlakeM]

Hi Jake,
Thanks for checking in.
Due to the winter low temperature, I am planning to install heat pump in the end of March 2023. Just review contractor's proposal now.
I will update you if it is OK with your suggestion.
Blake

[Jhonleanmel]

Hi BlakeM,

Thanks for letting us know. Take your time, We'll be waiting for your update.

Best,
Mel

[Jhonleanmel]

Hey BlakeM,

Checking back in should you still have some questions here. Let us know by replying to this thread.

Best,
Mel

[Jhonleanmel]

Hi everyone,

Just one quick final check in here since activity has slowed down. We'll be locking the thread in the next 24 hours, but if you still need help, I would be happy to keep it open. If there's more we can do, just let me know.

Thanks,
Mel

[BlakeM]

I do not need the further help now since I will install heatpump on the end of March 2023 . At that time I will ask question. Thansk!

[Jhonleanmel]

Hey BlakeM, 

It looks like we can consider this one complete, so I will lock the thread shortly unless I can help out with anything else. 

Best, 
Mel