A couple of weeks ago I noticed the heat was staying on in my office pretty much all day. I have a boiler heating system with 4 zones and the thermostat that controls the front of my house is right there in the office. I wasn’t cold in there, but the thermostat wasn’t reporting that the temperature ever reached what I had set.
I pulled the Nest off of its mounting bracket, put my hand near the hole in the wall, and I could feel cold air. So I grabbed an instant read meat thermometer and stuck it through the hole. The reading inside the wall was 10° lower than a foot away from the wall.
For a simple fix, I stuffed a bunch of insulation through the hole and covered it with foil tape.
In order to monitor the effectiveness of the fix, I put together a quick temperature sensor instead of having to turn the meat thermometer on and off.
Two or three years ago I had the opposite problem with this heating zone; it was always cold in the office. By feeling the wall I came to the conclusion that the thermostat had been installed right next to one of the pipes sending hot water to the upstairs registers. Brilliant! The fix that time was moving the thermostat over between the next set of studs.
After these two issues with the placement of a thermostat, I starting thinking. Why are we still basing our heating on measurements taken from a set position on the wall? With the Internet of Things we can do this much smarter.
Imagine each zone in the house having one or more mobile temperature sensors. Like the simple circuit pictured above, but in a small case. These could be battery-powered or plug-in. Windows, wind, and location of the sun can all affect the heating of different areas of a house. Being able to move the temperature sensor with you as you make dinner in the kitchen or watch a movie from your recliner would be awesome.
These temperature sensors would wirelessly report the temperature back to the home automation system. I use Home Assistant, which would make it easy to set the heating schedules for each zone. If a zone needed to go on or off based on the sensor’s reported temperature and the schedule’s target temperature, it would wirelessly trigger a relay module at the furnace or boiler. The relay would wire in to the furnace/boiler system in place of the wires that come from each thermostat and it would never know the difference. None of these pieces are hard to build and the parts are cheap.
This is all just something that ran through my mind as I was fixing my heating issue. I don’t have plans to build such a system, but if I did I could ditch my 4 Nest thermostats. For someone who works at home, often at random times of the day, I think Nest thermostats are overrated anyway because the learning and auto scheduling system doesn’t do much for me.