Winter is coming... warming up the house when 1916 tech meets 2020!

 I've just done a series on cooling the house, but now winter is coming... and, to be fair, this was actually one of the first home automations I actually did.

As mentioned before, I have an old house. Old for California. I have to deal with old wiring standards, and also an old heating furnace in the basement. Now, when I say old... I mean original to the house. So, at time of writing, it is 104 years old!

The 104 year old furnace

It is no longer wood or coal fired though. It has been converted to gas. It doesn't have any fans. It's all done by natural convection. Hot air rises! It works pretty well too. 

Floor vents for the heated air.

Yes, eventually I want to replace this, but it is all part of a larger plan of refurbishment of the house that is, slowly, turning into a monster project!

On purchasing the house, it already had a thermostat in the Dining Room, which controlled the heater down in the basement. So the wiring was there. At this point, I was oblivious to the intricacies of  wiring up a smart thermostat.

What I wanted was to be able to switch on the heater only when someone was in the house, so it required geofencing. I also needed to be able to define what that temperature was to be during the day, and at night... when all snuggled up in bed, with blankets on us, as well as our cats. 

Initially I used a Honeywell T5. When I went to wire it up I then found out that there was an extra wire I needed that I didn't have, which is the 'C' wire.

What is the 'C' wire I hear you say?

Back in the olden days, thermostats were simple on/off devices that didn’t need their own continuous power supply.  Modern thermostats with Wi-Fi and backlit display, by contrast, need a steady supply of juice.

The C wire, or “common wire” enables the continuous flow of 24 VAC power to the thermostat. 

Technically speaking, power flows from the R (red) wire, but not continuously (not on its own, anyway). To make it continuous requires a common wire to complete the circuit.  When the circuit is complete, 24V energy will flow continuously.

If your system doesn’t have a C-wire, you’ll need to run a new cable from your furnace to your thermostat to install most of the modern smart thermostat models. Or, if you have a power socket near by, you can also purchase a seperate 2Vv power supply, which is what I did.... mainly because when I opened up the back of the original thermostat I realise that the wiring was incredibly old and there wasn't much of it left.

Installation was, other than the short wires, very easy. The documentation was well explained. I ended up changing out the T5 though. It worked very well as a Thermostat, and did everything I wanted, but what it didn't do was be reliable with its connection to HomeKit. It worked most of the time, but not all of the time. If there is one thing I can't abide, it is unreliability.

Off I went and did a lot of reading on the net, and it seemed that the best option was the Ecobee Smart Thermostat. Even better, I got $50 back from PG&E for installing it... I could've got the same for the T5, but I didn't know about the program then, being new to California.

Again, installation was quite easy, and really only made difficult by the very short wiring that I have left in the wall.

I really would like to change this wiring out, it's just all around the big basement project.

Installed, the Ecobee looks pretty good. There was nothing wrong with the Honeywell, but I do think the Ecobee looks nicer. The only hame for me is it yet another app I have on my phone because I have a Honeywell Lyric security system, and so I use dto be able to use that for my Thermostat and Security. Still.... the Ecobee has never dropped out of HomeKit since I've had it.

The Ecobee also comes with an extra temperature sensor for another room. I already had that capability in most rooms, but not my living room, so it now it sits there.

Automation

I have 2 automations. The first covers 5am to 11pm, the 2nd covers 11pm to 5am. The only difference is that the day time one is a higher temperature.

Again, I had to use the Eve App as the Home App does not allow a trigger based on a temperature, even though HomeKit allows it. I then used the Home app to finish the automation as Eve only lets you automate scenes, which is great for complex set ups, but not good for simple ones where you're just acting on one device.

The logic is:

IF 

    the temperature in the Dining Room is 21C/70F or lower

AND

    the time of day is between 5AM and 11PM

          AND

              someone is home 

THEN

    Set the Ecobee to Heat to 23C/73.4F

ENDIF