I’m up to my armpits in alligators work-wise at the moment, so I’ll just leap into this blog with gusto and abandon (and aplomb, of course).

As you may recall from my previous column on this topic, I recently spent several months of doom and despondency with my new all-singing, all-dancing HVAC system from Bosch.

The cooling part is great. I won’t hear a bad word said about the little scamp’s ability to cool. It was the heating function that failed at the first fence.

This is a “dual fuel” system, which is supposed to use its heat exchanger down to an outside temperature of 35°F, at which point it switches over to auxiliary power, which is natural gas, in our case.

I’ve already talked ad nauseam about the problems we had with the auxiliary power portion of the system. My current rant concerns the graphical user interfaces (GUIs) for our ecobee thermostat and its iPhone app.

Just to set the scene, with both interfaces, when you are in the heating or cooling modes, you see little “flame” or “snowflake” icons, respectively. If you are already at the desired temperature and the system is currently not doing anything, then these icons are shown in white. If you are actively heating, the flame icon turns orange; if you are actively cooling, the snowflake icon turns blue. I have no problems with any of this.

My first issue is that the graphical interfaces on the physical thermostat and the virtual app are different. Some variation is inevitable, but since both rely on touchscreen interaction, they should look and behave as similarly as possible, with differences kept to a minimum.

Some issues are just minor niggles, like the fact that when you attempt to change the mode, you are presented with a 4-item list:

• HEAT
• COOL
• AUX
• OFF

Personally, I would have arranged this differently, grouping the two heating modes together as follows:

• COOL
• HEAT
• AUX
• OFF

Another niggle is that the thermostat indicates the currently active mode by showing black text on a white background (while inactive modes show white text on a black background). By comparison, the app shows all modes as white text on a black background, using a checkmark to indicate the active mode. As I said before, this is a minor niggle, but it’s still a niggle, and I’m not in a good mood at the moment, so any niggle makes things worse.

I can instruct (force) the system to use auxiliary heat, which can be advantageous if I want to heat the house rapidly for some reason. In this case, the physical thermostat slightly modifies its flame icon, adding the text AUX in small letters. The virtual app… doesn’t. The only way to tell if you are using AUX heat from the app is to dive deep into its esoteric menu system.

It gets worse. As you can imagine, I’m sensitized to the AUX heat not working due to all the problems we’ve had, so you can only imagine how I felt the morning after the system was supposedly fixed (for the last time) when I glanced at the thermostat and saw only the regular flame icon, even though the outside temperature had plunged to below 20°F.

Naturally, I assumed that the AUX heat had failed again, but no! It turns out that the system treats the standard HEAT mode as encompassing both heat pump and auxiliary heat sources; it only deigns to display the AUX text if you’ve physically set the system to AUX mode.

After several weeks of rooting around the thermostat’s arcane menu system, I’d grown to believe there was no way to use the physical thermostat to determine whether the system had automatically switched to AUX heat. And then, when I least expected it, while spelunking in the menu’s depths, I found a page that said something like “Equipment running: AUX heat.”

I couldn’t believe my eyes. I was very excited. I was so excited that I came back later to verify what I’d seen. Sad to relate, I couldn’t find the location of that entry in the menu’s hierarchy a second time. If obfuscation was the goal of the system’s designers, then I can only say “Well played! But if their intent was to create something intuitive and easy to use, I can but cry, “For shame!”

I could waffle on about this for hours, but what would be the point? Good user interfaces obey a few simple principles: consistency, clarity, and visibility of system state. When those principles are ignored, even a sophisticated piece of hardware can become confusing and frustrating to use.

The ecobee thermostat may control a very clever HVAC system, but its GUI feels like it was designed by people who never actually had to live with it. At the end of the day, a brilliant system fronted by a confusing GUI isn’t a good product—it’s just an expensive puzzle.