Any updates on Linus's local-only HomeAssistant HVAC integration?

[computerace]

Does anyone know if any progress has been made regarding Linus's quest to eliminate the cloud from his American Standard (or similar) HVAC setup at his new house?

 

I don't know much about HVAC but am curious to talk with anyone who may be familiar with various different aspects that would be needed to build a solution like this such as:

• HVAC systems owned by the Trane corp like American Standard, particularly with regard to the thermostats themselves
• FPGA's and hardware debugging
• Building homeassistant integrations
• Networking, security, systems/OS programming
• experience building other open things that work with closed platforms
• honestly whatever else you think might be useful

At this point I'm not sure what I'm doing but I'm interested to learn as much as I can and give it a shot (even if it takes a while) in the hopes that I either end up getting something working, or finding someone else's better approach that I can contribute to.

 

[Lurking]

I assume you have a US home furnace with gas heat and AC. The furnace itself has its own control (just simple relays,delays, timers etc.) to make sure the fan runs when it should (like a few seconds before AC compressor turns on, but not before as burnet turns on). Your AC condenser outside also houses the compressor and ensures the fan runs before the compressor. There are safety switches etc. Those ensure your flame is on when the gad valve opens.

 

That all is old school and pretty similar between Trane, Carrier etc.

 

Your thermostat or Nest, mercury thermostat and so on, basically just closes a contact for cool, fan, and heat. This thermostat is called the "controller" in HVAC. We call it digital. But in HVAC just means on/off. Like thermostat closes the "heat" contact, then the furnace starts the burner sequence and the fan.

 

INn a fancier home system you can have multiple stage AC, burner and fan and the above just has more digital on/off signals.

 

In commercial systems you also have analog signals. That could be a 0-10V or 4-20mA,bor 1-5V etc. Unlike a digital (which is just on/off) this can tell the device a specific value from 0 to 100%. So instead of just turning on a burner at full fire, it could tell the burner to run at 56%. There also are protocols like BACnet. But really, you don't have that in a home. 

 

Now the thermostat or controller could be anything and that is why you can easily can add a Nest to replace your grandma's mercury thermostat. To decide when to heat it could just be a mercury switch, or an IoT device that uses weather data. Most homes have a non IoT programmable thermostat. Those controllers often have the temperature probe built in. But it also could be remote at a better location (at a return for example).

 

As for security, I doubt any of those IoT devices have much of that and the manufacturer will have all your data (like if you heat at 5pm, they know this may be when you come home). Some also have motion sensors. So there is all that. A regular programmable thermostat without Internet is dumb enough to be secure.

 

 

[computerace]

Thanks for the info! It seems like a lot of companies installing newer/more modern heat pump systems - especially those variable speed ones - seem to be going the more "digital communication" route and creating proprietary protocols that lock you into their thermostat. Based on my research it seems like that's the kind of system linus had installed and wants to integrate with homeassistant (but cant because the existing integration relies on the manufacturers cloud service and doesn't have a local-only way to control it)

 

 

[Lurking]

4 hours ago, computerace said:

Thanks for the info! It seems like a lot of companies installing newer/more modern heat pump systems - especially those variable speed ones - seem to be going the more "digital communication" route and creating proprietary protocols that lock you into their thermostat. Based on my research it seems like that's the kind of system linus had installed and wants to integrate with homeassistant (but cant because the existing integration relies on the manufacturers cloud service and doesn't have a local-only way to control it)

 

 

Some things in an HVAC device will be proprietary and it is good that you can't access them. For example, the AC compressor speed will need to accommodate proper oil return and not freeze the coil. 

 

But the overall control (like telling it to provide 70% heat) often is an open protocol, like BACnet. So you can use a Honeywell controller for a Mitsubishi heatpump. You just need to buy the BACnet Interface from Mitsubishi.

 

I don't know if those residential home IoT devices are as open as commercial systems, though. I don't know what Linus has. 

[Donut417]

2 hours ago, Lurking said:

I don't know what Linus has. 

I dont know the exact system but Im pretty sure he has radiant heat. I recall he has electronic valves that provide zone control or something to that nature. 

[Lurking]

13 hours ago, Donut417 said:

I dont know the exact system but Im pretty sure he has radiant heat. I recall he has electronic valves that provide zone control or something to that nature. 

I assume hydronic tubes in the floor. H then still needs a heatpump or a fuel boiler to heat that water. And a pimp that all needs to be controlled. It also won't cool or dehumidify, so he sure has some air-based system.

[Donut417]

5 minutes ago, Lurking said:

so he sure has some air-based system.

Most likely a ductless system. As that would also have zone control vs a force air system. 

[computerace]

On 7/1/2023 at 7:22 PM, Lurking said:

I don't know what Linus has. 

From some past videos, i think he has essentially two systems (i.e. 2 thermostats per zone), one with ecobees thats hooked up to the in floor hydronic heat, and one using American Standard XL1050 (i think) thermostats with a heat pump system for forced air cooling. It seems like the floor heating is meant to provide a stable base house temperature anf the air is for the variable stuff and per-room control like hea trying to do with the smart switches