Idea for thermostat merging?

Here’s the problem, two thermostats in the same place, one for AC (only cooling) one for Heat (only heating).
As it’s a rental place, people coming are often switching on both heating and cooling which make no sens.

I was wondering if there was any way to merge these two thermstats in one ?
If Heat nedded => Heat On Ac Off
If cooling needed => AC On Heat Off

Any idea ?

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What did you try so far?

Automation using Node Red but something tells me there’s a simplier way of doing things, and I should confess I’m not satisfied with my automation.

Replace the two thermostats with a single one that supports both heating and cooling?

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:slight_smile: I can’t, one is cabled to the heating system, the other one is sending commands to the AC using IR. I’m stuck with these.

How is Home Assistant controlling that one?

if they can share the same power source install a DPDT switch to only activate one thermostat at a time

That I can do with Wifi driven plugs but I’m quite sure I’ll get problem each time they get online as they’re both Honeywell and Honeywell is cloud poll.

or make the tenant pay the utilities that usually puts a stop to wasteful habits

I’m looking for a Home Automation solution not a financial one :slight_smile:

So you’re using Home Assistant’s Honeywell integration to control both the heating and cooling systems?

Yes but it’s getting offline very often.

I imagine you are already aware that any ‘merged thermostat’ proposal will rely on the existing methods used to control the two separate thermostats. So if it’s unreliable now, it’ll continue to be unreliable when merged.

Off the top of my head, I can see a way of using MQTT HVAC to define a third climate entity that controls the two existing climate entities (one for heating, the other for cooling). In effect, it acts as an amalgamation of the other two thermostats, able to control heating and cooling; when it needs to heat it turns off the cooling thermostat and controls the heating thermostat, when it needs to cool it turns off the heating thermostat and controls the cooling thermostat.

The automations needed to perform this balancing act will be interesting … and potentially a waste of development time if the underlying ntegration for the two thermostats is unreliable.

Have you seen this?

Dual Mode Generic Thermostat

That looks interesting. What are your thoughts on how it can be used to control two climate entities (as opposed to two switches)?

I would think that two Template Switches could do it.

Alternative to merging two disparate climate devices which has its own complications.

Why not a “deconflict” automation for the climate devices you have now?

So when the heating Template Switch is on it sets the heating thermostat to a high target temperature? At the same time it also turns off the cooling thermostat.

Similarly when the cooling Template Switch is on it sets the cooling thermostat to a low target temperature? At the same time it turns off the heating thermostat.

You got it. That’s the idea.

A potential crux in the dual-generic thermostat idea is if someone tampers with any physical temp buttons on the actual thermostat.

As I have an IR AC, the solution was a ‘watchdog’ automation based on power usage.

So if the only goal is deconflict, not singular control interface, then perhaps consider just using an automation that monitors the state off both and one turns off the other. Because merging is not necessary to deconflict.

The concern I have is that Vartkat has already confirmed the underlying integration can be unreliable. Imagine the Template Switch turns on and sets the heating thermostat to a high target temperature (75 F/24 C) to ensure the device activates … and then the integration loses communication. The heating thermostat will dutifully continue heating until the target temperature is reached.