Nest thermostat wattage

[Bardiya]

I have 2 step-down 24V 40VA transformer that each feeds 3 zone-valves (Honeywell 0.32 Amp). I have installed 6 Nest Thermostat to my heating only system but my previous thermostats all had R and W wires (no C connection). Since I do not have a controller board, I am going to use one Google Power Connector per thermostat at zone valves. I want to ensure 3 zone controllers plus 3 Nest thermostat with 3 Google Power Connector could be supported with one 40 VA transformer which has 0.70 watt left. My question is how many watts each Nest thermostat with power connector need?

[ByronP]

Hi Bardiya,

Thank you for posting in the community. I understand that you would like to know how many watts you need for each Nest Thermostat to connect with their Nest Power Connectors. I'm here to help.

Before I begin. I need to ask a few questions for further assistance:

• What type of Nest Thermostat do you have? (Here is the link on how to identify the type of Nest Thermostat.)
• What is the distance between the power connectors and your Nest Thermostats?
• Can you please send a picture of your current HVAC system?

Keep me posted. I look forward to your response.

Regards,

Byron

[Bardiya]

Thanks for your message.

Answers to your questions:

Google Nest Thermostat

distance between power connectors and thermostats varies, approximately 5 (basement) to 15 meters (2nd floor bedroom).

No HVAC, only a tankless heating system (hydronic floor radiant system).

 

[ByronP]

Hi Bardiya,

Thank you for your response. I appreciate all the information provided and the picture you've sent.

Based on your answers, if you have a Google Nest Thermostat, the voltage required should be 20-30 V AC, and the power consumption is less than 1 kWh/month, so the recommendation is to have 24 V AC required to work properly. If you have more than that, it will overpower your thermostat once you connect the Nest Power Connector. Here is an article about the technical specifications of the Nest Thermostat.

Also, here is the article to check the technical information about the Nest Power Connector required for the Nest Thermostat.

Please let me know if you have any further questions.

Regards,

Byron