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Comment by HeavenFox | Hacker News Reader

FYI this kind of thermostat is actually better. American style thermostat put your HVAC system in either on or off state (basically PWM), whereas this kind of communicating thermostat can tell the system what the temperature is, so they adjust power accordingly. I do wish they have standardized protocol though.

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Single stage hvac systems tend to have better performance in the max capacity cooling cases (Texas) and last significantly longer than units that rely on non-linear electronic devices.

The difference can be as extreme as 10+ years of service life. There are residential systems that were installed in the 80s and 90s that are still running fine today. The hermetically sealed scroll compressor is an engineering marvel. The electronics will generally fail before any meaningful mechanical wear is incurred.

Single stage forced air / air handlers AC systems are basically only found in North America because they are so grossly inefficient and because most people in the rest of the world realize they can save money by not having all of their rooms ran off the same system. The rest of the world runs on mini splits for that reason.

I don't understand why it's so common for Europeans to act like they speak for the entire rest of the world outside of North America.

>Single stage hvac systems tend to have better performance in the max capacity cooling cases (Texas) and last significantly longer than units that rely on non-linear electronic devices.

Why?

Inverter systems have more conversion losses than single stage. Most of the time, I definitely intend to run my system as hard as it can. There are only 4-5 weeks out of the year where variable speed would make a meaningful difference.

Semiconductors wear faster than copper wires and contactors and are much harder to replace. I can take a part from my neighbor's condensing unit and it would almost certainly work in mine. The make/model is largely irrelevant. I can go on Amazon, search "Start+Run Capacitor" and buy the first thing I find.

> Most of the time, I definitely intend to run my system as hard as it can. There are only 4-5 weeks out of the year where variable speed would make a meaningful difference.

The system never catches up, even at night?

Because all too often the electronics are what fail and replacement parts are not available so the whole thing is scrap even though the compressor is still good.

The thermostat is better only because it takes advantage of the inverter modulation capabilities in the heat pump. I don't have the sense that inverter modulation is the norm for most home ducted systems, even new builds in North America.

I've only observed ductless systems like this in retrofitted, older homes in Canada. And at that point they're usually not integrated with the home's existing heating system / thermostat.

It is starting to happen in the US as well.

In some countries there are devices supporting the OpenTherm protocol: https://en.wikipedia.org/wiki/OpenTherm https://www.opentherm.eu/

Depends on your definition of better.

It's a tradeoff I'm willing to make for simple, open I/O. It's not PWM but rather a "call" for heat, cooling, or fan. If I'm refinishing the wall I can (and have) put in a $3 thermostat in its place so I don't destroy the $300 one with paint and dust.

It's also very easy to debug and repair, as I experienced on a day when the temperatures exceeded 100F and was able to execute an emergency repair myself.

If companies like Nest and Ecobee were not allowed to exist, we would all be stuck with the overwhelmingly universally overpriced, proprietary garbage the OEMs put out.

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