Home Technology

A couple of months ago, we swapped out our old programmable thermostats with new Nest learning thermostats … and we’ve been really happy with them.  Although there’s a lot we like about the Nest, one of the features we’ve missed from the beginning is the ability to analyze all of the data collected by the thermostat.  Access to this data is listed as one of the top requested enhancements on the Nest community site, but as of now, the only data that’s available is the energy usage graphs for the past 10 days.  While this is an ok start, the data isn’t viewable until the next day and this history isn’t there to be able to do any meaningful analysis.

While we still hope that the Nest provides official access to all of the behind the scenes data in the future, Chad spent some time this weekend working on an alternate solution that we think will be really useful in the meantime.  It’s based on this (unofficial) Nest Learning Thermostat API, which accesses the Nest website to retrieve status information for both of our thermostats.

We’ve used the API in a simple .php script that’s scheduled as a cron job on our server.  Once we’ve retrieved the information from the Nest website, we’re using Zabbix as the logging and charting platform for putting together some graphs that provide an at-a-glace overview of temperature,  humidity, and status (running or not) for each thermostat.  Here’s a snapshot of the graphs we’ve configured initially:

While Zabbix may not be the obvious choice for charting temperature-related data, we already had it in place for monitoring availability of our networked devices, so it was a matter of simple configuration to add the Nest data to it.  In addition to enabling the charting functionality, Zabbix also provides the ability to configure alerts based on trigger points.  We’re still thinking through how we’ll make the best use of this, but it would be a simple thing to send email or SMS alerts when the furnace is running, when the temperature has reached (or fallen below) a threshold, when the furnace hasn’t ran in a defined period of time, etc.  This functionality has also been logged as a feature request on the Nest community site.

We’ve initially chosen to poll the Nest website for updated data every 5 minutes, which accounts for latency between the Nest thermostats and the data on the website.  Although it would be  better if we could connect directly to the thermostats for actual real-time data rather than going to the website for updates, the 5 minute interval is certainly close enough to real-time to meet our needs.

While we’ve only been logging data from the Nest thermostats for a little over  a day, we’ve already noticed a couple of things:  1-Nest seems to do really well at keeping the house temperature within a pretty tight range of the set point temperature.  2-The closer-to-real-time nature of the data is allowing us to pick out some trends that will likely influence our behavior going forward.  For example, the upstairs furnace runs longer to maintain the same temperature when the door to the master bedroom (where the thermostat is located) is closed.

Pretty cool, huh?

Nest Thermostats

Over Christmas vacation, we installed two new Nest thermostats.  One was a Christmas gift and (after seeing how cool it was) we ordered the other online and installed it upstairs.  We’ve only been using them for about 6 weeks, but so far we’re really liking them.

The Nest for the Main Floor (installed in the dining room)

The Nest for the Main Floor (installed in the dining room)

The Nest for the Second Floor (installed in the master bedroom)

The Nest for the Second Floor (installed in the master bedroom)

We love the way they look in both locations – much more streamlined and unobtrusive than the old touch screen thermostats we had.  Probably more than that, though, we love the fact that they’re internet enabled so we can adjust the temperature from anywhere in the house or even from the car (so the house will be all warmed up by the time we get home).  We also like being able to set the “away” status of both thermostats at the same time from the iPhone app (one of the benefits of having multiple Nests), but since Haley and I are home most of the time, we haven’t yet turned on the auto-away feature.

Installation was really simple.  We took a photo of how the old thermostat was wired and used the online tool on the Nest website to map that wiring to the new thermostat.  Easy peasy.

The Wiring for the Old Thermostat

The Wiring for the Old Thermostat

The wiring for the Nest

The wiring for the Nest

To be honest, the “hardest” part of the installation in both cases was touching up the paint around the new thermostat since the paint in both rooms had been applied around (and not behind) the old thermostats.  We had the left over paint in both cases, but had mixed results in touching up the walls.  Everything turned out fine in the dining room, but the bedroom paint doesn’t quite match up – I guess that’s what happens when you try to paint a patch in the middle of a wall that was last painted 5 years ago.  It’s good enough for now, but we’ll probably wind up re-painting the wall sometime later on.

So far, everything about our installation of the thermostats has been working exactly as expected.  Our only concern going forward is that the thermostat is designed to do what Nest calls “power sharing”, which means that the it charges the battery by using power from the circuit only when the furnace (or air conditioning) is running.  This is discussed a lot on various forums as a concern – some folks have issues with it, others don’t.  So far, we haven’t seen any problems, but our plan is to keep an eye on it as the weather changes and the furnace runs less.  At that time, we’ll probably update the wiring for both thermostats to make use of the “C” wire, which is a common ground that would allow the Nest to charge as needed without the unit running.

We’re also super excited about how the Nest will continue to improve and evolve over time.  A new forum was recently launched to provide a place for the Nest community to request and vote for enhancements to the current Nest solution.  We’re pretty excited about the top two items on the list:  1- increased access to the data that’s collected by the Nest (the reports currently provided are ok, but not great and not available until the next day) and 2- a networked thermometer accessory that could be placed in a location separate from the wired thermostat.  For us, this would be really great since Haley’s room (which is on the second floor of our house) is serviced by the furnace on the main floor since that was the easiest (only?) way to get duct work to the room when the house was re-fitted with a forced air system.  It works fine except that it causes us to heat the main floor of the house probably more than required in an attempt to keep her room at an acceptable temperature overnight.  With a networked thermometer that we could place in her room and link to the Nest on the main floor, we would be able to tell Nest to run the downstairs furnace to maintain the temperature according to the thermometer in her room at night and the main thermostat in the dining room during the day, which would eliminate the guess work.

Anyway, so far, so good.  We’re happy with how the Nests are working for us so far … and excited for what’s (hopefully) coming!

While walking through Lowe’s this weekend, we saw a new end display of products for monitoring energy usage.  One of the new products on display was the Kill-o-watt, which we were happy to see is now available locally – we looked everywhere for one a couple of years ago and finally had to order online since none of the local retailers carried them.  Also on the same display were two new products from Black and Decker – a Power Monitor and a Thermal Leak Detector – and the TED 5000 Energy Monitor.  The energy monitors really caught our attention since we’re always curious about how much power we’re using and what the biggest usage items are.

Both of the energy monitors at Lowe’s are for measuring the usage of the entire household.  After doing some research online, we went back today and purchased the Black and Decker Power Monitor.  What we found is that the Black and Decker model includes a sensor that straps on the power monitor (a list of supported power meters is available here) and then a wireless display for reading the real-time usage.  The TED 5000 model includes two clamps and a “gateway” that needs to be installed in the main electrical panel.  Usage information is then communicated to a wireless display and can also be tracked using Google PowerMeter.

We decided on the Black & Decker Power Monitor because we preferred to install the sensor on the meter outside than mess with the electrical panel downstairs.  After researching online, we also found that it is actually the same product as the Blue Line Innovations Power Cost Monitor and there’s also a Blue Line Innovations WiFi gateway for tracking the usage over time on the Microsoft Hohm website.

Black & Decker Power Sensor

Wireless Display

We installed the power monitor this afternoon and have been monitoring our energy consumption pretty closely for the last couple of hours.  The device seems to be pretty accurately displaying our usage and adjusting as the refrigerator, dehumidifier, pool pump, etc. turn on and off.  It’s really interesting to see the real-time energy information, but we think the true value is in being able to graph the usage over time and use that information to adjust the timer for the pool pump or the programming of our thermostats.  So, we’ve placed an order with New Egg for the WiFi gateway that will allow us to view the usage (real-time and historical) on the Microsoft Hohm website.  The gateway should hopefully come yet this week, so we’re hoping to have it up and running by next weekend.

So far, we’re pretty happy with the purchase – and we’re excited to see how much of a difference we can make in our energy usage after getting a better feel for what our usage looks like over time .

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