Not Always Smart Thermostats

I can't picture how you, the dear reader, are reading this article; but I'd make a somewhat safe guess that you are surrounded by the atmosphere.

Let's imagine that a supernatural event teleports you, right now, to floating in the vacuum of the outer space. You get a glance of the earth before feeling you are about to explode. The air violently and painfully rushes out of your lungs, your body starts to severely swell, the water on your eyes starts to evaporate, and you start to suffocate.

But you won't freeze.

Instant freezing in the outer space is a pretty common misconception. You may remember scenes of it in movies (opens new window) and cartoons (opens new window). I don't know why this was being even shown to kids. Old times.

It makes sense why people would make up that freezing theory. It is because we say:

The temperature of the outer space is close to the absolute zero.

A completely true and scientific statement. So, one would think that when they get exposed to the space, their 37°C body temperature will quickly fade into the extreme coldness of the outer space. Just like when one falls in a frozen lake.

The problem with the frozen lake analogy is the existence of water. In the lake, the water is freezing and it touches your skin -- therefore quickly extracting the heat. In the outer space nothing is touching your body. If there isn't anything to extract that heat like water, where would the heat go?

To answer the question, let's remind ourselves that in addition to the heat transfer through contact (conduction/convection), there is another way energy can move: radiation.

Between the earth and the sun there is no physical matter to conduct the heat. The sun's heat gets to us as radiation. It's definitely a good thing, because if there was matter between us and the sun, we would have had to deal with deafening sounds of the sun's explosions (opens new window).

But it's not just the sun that radiates. You radiate too.

The energy/wavelength of radiation correlates with your temperature. The sun is extremely warm so it radiates in all sorts of levels, including the visible spectrum. You are only a little warm, so you radiate in infrared. That's how nightvision sees you. The cameras are sensitive to your wavelength.

In the outer space, you still have a glow, but the space gives you almost nothing back because it is so cold. You start losing energy to the emptiness of space. The flow of energy however, is not nearly enough to freeze you instantly.

In fact, the low rate of radiation is a bit of an issue. The International Space Station has as much heat rejection panels as it has solar panels. They need all that surface to get rid of the heat generated onboard.

Let's get back to the earth. Congratulations, you just installed the latest smart thermostat technology in your home. So why nothing feels any different?

# The Science

Thermostats are given an impossible task. From the outside it looks like they keep a temperature, but in reality, a good thermostat just make sure that the temperature it gets hovers around the target with the least number of heating system cycles. Turning a mechanical system on and off constantly reduces its lifetime. So the original idea is not really the temperature but the usage pattern.

To that note, any functioning, well-balanced thermostat should be able to achieve that. Though, could you do more? Maybe with AI?

This is the business case for the gazillion startups that tried their hand, and to their dismay, nothing came out of it.

Why? because what else is there to do!? Perhaps you were hoping that a smart thermostat will make the space more comfortable. The thermostat can't do much about radiation, and what it does about the air temperature is hardly any grounds to say it will make someone comfortable.

How about scheduling, usage patterns, and energy saving? Perhaps they would be helpful but smart thermostats have not introduced these concepts. Moreover, things like learning the usage pattern do not necessarily lead to more comfort.

Say, you want the thermostat to be off while you are at work, letting the home to get really cold. If you are at work for an extended period, this can help reduce envelope heat loss. When you are back your heating system needs to work hard to bring back the temperature up spending a lot of energy in the process. After that, your home's shell and the furniture are not as warm as the air, making you feel cold.

In the meantime, people change, seasons change, and behaviours change. A normal thermostat has a single layer of interaction with the use. With all its shortcomings, the output of it is rather predictable. Any added level of smartness makes the outputs fuzzier. Maybe the smart thermostat is using the preference of someone who doesn't live there anymore.

# The Promise

Smart thermostats have become a way of greenwashing in residential buildings as well.

Picture a home with basement leaks, drafty windows, mold, and rodents all over the place. You rip off the old thermostat and replace it with a Nest. Welcome to your smart home!

Smart thermostats promote active maintenance of the home which in my opinion is the wrong way of retrofitting. Active maintenance is constantly monitoring the building and works to compensate for the problems. Compensate is the key word here because the building is not functioning correctly to start with.

Our homes, just like ourselves should be considered living, breathing things. They must passively respond to the occupant needs. The vase majority of homes do a very poor job on that front but this doesn't have to be the case.

Reducing heat loss by adding insulation, draft-proofing of the places air flows in the walls, and adding more modern ventilation solutions will fix many of the hidden and apparent issues people have with their buildings. These changes also add resilience. Your heating system is useless if an event has cut down the fuel supply.

Of course the passive upgrades of the home are costlier and more involved. Worse yet, they are not things to brag about. These issues have opened a big opportunity for devices that sell the idea of a better home, more than actually delivering one. If only it was that easy.