Thermostat Upgrade

When I first heard of the company called Nest, and how their few hundred dollar thermostat was sought after, I had rolled my eyes. It's a thermostat! Why do you need to upgrade it, much less to one that costs an arm and a leg? Made no sense to me then. Fast forward a few years, and having kids who expect to be able to talk to devices and get instant results, I had to reconsider. More over, PG&E has a generous rebate program going for connected, "smart" thermostats. So why not?

The thermostat that came with this 36 year old house is a thing of antique beauty. Just look at this clever electro-mechanical contraption. You can figure it out if you just stare at it long enough! It's so quant, so cute! I never wanted to let go of it. 

But, apart from not satisfying the need to command devices with one's voice, this antique didn't give me a "fan only" option, which I can really use in this AC-less two story house in the summer months (just to circulate the cooler air from downstairs to upstairs, and even the temperature out). 

So it has to come off the wall and likely go into the showcase!

But, before I could take the plunge with a WiFi connected, "smart" thermostat with ears, I needed to ensure the furnace is not equally antique. Which it turned out not to be, thankfully. I had got a tip from the furnace repair guy who had come in a couple of weeks ago that there is a provision for the "common" wire, and the "fan" wire, but they aren't hooked up. He could do a professional job of hooking them up and give me "peace of mind" for about a $100. He could even sell me a Nest thermostat for $300 something and install it right away. No thankyou. I need to do my research.

I ordered the latest Nest thermostat which is a "mere" $129, along with the matching trim plate for another $15, assuming I can just 'figure it out'.

It took some figuring though. First, to ensure that wires were indeed "low" voltage (but not "millivolt") you just need to look at what's behind the existing thermostat. What you want is single-strand wires, with no heavy-duty wire nuts and nothing that mentions 120V or something like that. Good to go on that front. But staring at this some (and at the back of the old RobertShaw), it was apparent that only two wires were in use. So the technician's tip made sense. 

But to be sure, and hopefully to be able to hook up the common and fan wires, I needed to open up the furnace and get into the control board

Bingo! Only two wires connected - the R and the W. (R is power, and W controls the heat). But two other wires were readily available in the bundle, and I simply need to insert them into the C and G slots (common and fan respectively). 

At the other end, removing the old baseplate was a bit of a pain, and what lay behind was an eyesore. A very crudely gouged, unnecessarily big, hole in the dry wall. So I patched it up with some wood putty (that's all I had on hand) and covered with a small sheet of paper so that the new baseplate doesn't stick to it permanently. 

Also, with a multimeter, I measured the voltages, and as expected, R to C was a little over 24V(AC), and the others were 0. Good. 

Now I had to worry about aesthetics a bit. Because the hole is considerably off center of the previous foot print, whereas the Nest wants to be centered perfectly, even with the large trim plate, I had an ugly exposure. 

Luckily, I found the paint in the shed, that the previous home-owner had left behind years ago, and the paint hadn't dried up. It needed several coats though, and the end result wasn't bad!

And oh, it all works too. Talking to the Google Home speaker and telling it to adjust the thermostat is kinda cool! The sci-fi world we already live in!!