topic Re: Natural cooling without AC ? in Nest Thermostats

Natural cooling without AC ?

marcjero — Thu, 15 May 2025 15:37:37 GMT

Hello,

I want to wire a ventilation system to aq+ in order to get natural heating and cooling. However I don't have any AC system. Nothing is connected to the y wires. I would like to know if natural cooling does work even if I don't have any cooling system connected to the thermostat. Please say yes 🙂

Thank you

Re: Natural cooling without AC ?

GabrielaG — Sun, 18 May 2025 20:03:47 GMT

Hi @marcjero,

Thanks for reaching out to the community. I understand that you want to wire a ventilation system to AQ+ in order to get natural heating and cooling, and I'd be happy to help.

Please help me out by answering the following questions:

Is your Nest Thermostat a Nest Learning Thermostat 4th gen?
Can you please send me a picture of your thermostat wiring?

Any additional details you can provide will be helpful.

Best regards,

Gabriela

Re: Natural cooling without AC ?

marcjero — Sun, 18 May 2025 20:48:42 GMT

Hi Gabriela,

thank you. Yes the device is a Nest Learning Thermostat 4th gen.

I'm not at home so I can't take picture. I did a conventional 2 stages heating wiring using 24v ac converter and relays to activate my heating systems.

I wired this way :

C: 24v ac (common wire)

Rh: 24v ac (power)

W1: first heating system (thought relay)

W2: second heating system (thought relay)

I don't have any AC system therefore I didn't wire anything else.

Best,

Jerome

Re: Natural cooling without AC ?

GabrielaG — Mon, 19 May 2025 01:17:07 GMT

Hi @marcjero.

Thank you for your reply. I appreciate you taking the time to respond to my post and for providing information about your Nest Learning Thermostat 4th gen. I'm happy to help you with the wiring.

After reviewing the wiring information, it appears you only have a heating system. In this case, it's not recommended to connect a wire to the AQ+ terminal. This terminal is intended for air conditioners with humidity control. Connecting it to a different type of HVAC system could cause damage.

If you would like to use air conditioning and the AQ+ wire, you should contact a technician who can assist you with the wiring.

Feel free to keep us posted if you have more questions.

Best regards,

Gabriela

Re: Natural cooling without AC ?

marcjero — Mon, 19 May 2025 06:08:43 GMT

Hi,

Thank you Gabriela. I don't use HVAC system at all and I don't plan to install an air conditioner. I use electric heaters and gas heater. And I have a ventilation system that regulates humidity. Now it's clear for me that the natural heating and cooling features are only working for HVAC systems.

But is that not a bit weird ? I mean that natural cooling should save energy for cooling but we must run AC at the same time, which is not really good for the planet.

Best,

Jerome