Help to make NEST work without connecting to HVAC system


Hi there,

I’m Mark and we are actually creating an AR application similar to this ->

We will connect via API to Phillips Hue lighbulb and NEST thermostat. The problem is that we want to put NEST on a wall in an EXPO environment without connecting it to a real HVAC system but we want it to work (kind of :)).

In our app, in regards to NEST, we will be using a slider to change the temperature of the house and we would need NEST screen to reflect the changes of temperature in real time so that people can see that we can control it via the app.

Therefore we need NEST to be operational without connecting it to any system and for example without it showing “please connect me to XYZ”

I have receive information on NEST helpline that I will receive blueprints or something that will help an electronic engineer set up a board in order to hook up to NEST and make this happen - however it’s been 2 weeks and nothing happened.

Can anybody help in that?

If more clarifications are needed please let me know,
Thank you very much,


Hi Delivr,

You can do this by connecting 24V AC power to C and Rh terminals (to preserve the battery) and a resistor of 1.6-2.0kOhm (0.5W) between C and W1 to simulate presence of a relay.




There’s an old thread about this here:



Hi again,

We don’t have official instructions on what’s best for you to do. However, we do have these schematics, photos, and a parts list. Make sure someone who’s an electrician does the work and provides professional advice.